The paratesticular area includes a variety of anatomic structures,

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1 PICTORIAL ESSAY Imaging Features of Paratesticular Masses Mustafa Secil, MD, Michele Bertolotto, MD, Laurence Rocher, MD, Gokhan Pekindil, MD, Tiziano Stocca, MD, Jonathan Richenberg, MD, Parvati Ramchandani, MD, Lorenzo E. Derchi, MD, on Behalf of the European Society of Urogenital Radiology Scrotal Imaging Subcommittee In this pictorial essay, we review the sonographic and other imaging findings of paratesticular masses in correlation with the pathologic findings. The examples include benign and malignant tumors and also non-neoplastic mass lesions of the paratesticular structures. Diagnostic sonographic findings of these mass lesions as well as correlative findings of other imaging methods are presented. Key Words genitourinary ultrasound; imaging; paratesticular masses; sonography Received July 11, 2016, from the Department of Radiology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey (M.S.); Department of Radiology, University of Trieste, Trieste, Italy (M.B.); Department of Radiology, Bic^etre Hospital, Paris, France (L.R.); Department of Radiology, Faculty of Medicine, Celal Bayar University, Manisa, Turkey (G.P.); Department of Radiology, San Giovanni di Dio Hospital, Gorizia, Italy (T.S.); Royal Sussex County Hospital Brighton and Brighton and Sussex Medical School, Brighton, Sussex, England (J.R.); Department of Genitourinary Radiology, University of Pennsylvania Medical Center, Philadelphia Pennsylvania USA (P.R.); and Department of Radiology, Dipartimento di Scienze Della Salute, University of Genoa, Genoa, Italy (L.E.D.). Revised manuscript accepted for publication September 13, Address correspondence to Mustafa Secil, MD, Department of Radiology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey. Abbreviations CT, computed tomography; MRI, magnetic resonance imaging doi: /ultra The paratesticular area includes a variety of anatomic structures, which include the tunica vaginalis, epididymis, ductus deferens, spermatic cord, vessels, lymphatic channels, and other supportive tissues of the testis. 1 8 Space-occupying lesions originating from these structures may be non-neoplastic or neoplastic. Nonneoplastic lesions include epididymal cysts, spermatoceles, fibrous pseudotumors, spermatic cord cysts, spermatic cord lipomatosis, and polyorchidism. Neoplastic masses may be either benign or malignant. 9 Among benign neoplasms, there are adenomatoid tumors, papillary cystadenomas, and benign mesenchymal tumors. Lipoma is the most common mesenchymal tumor, followed by leiomyoma. Malignant neoplasms are mostly mesenchymal in origin, such as rhabdomyosarcomas, leiomyosarcomas, liposarcomas, undifferentiated pleomorphic sarcomas (formerly known as malignant fibrous histiocytomas), and other extremely rare ones. Metastases to the paratesticular region may occur secondary to various primary tumors. Involvement from hematologic malignancies may also be observed. The principal method of examination for the paratesticular structures is sonography, which is nearly 100% sensitive for detection of lesions in the scrotal area. However, the specificity is lower, around 70% to 90%, depending on the location and the characteristics of the lesions. 1 8 Magnetic resonance imaging (MRI) may be an alternative or additional method for lesion characterization Computed tomography (CT) may be used for the staging workup of malignant lesions. In this pictorial essay, the imaging features of a wide variety of paratesticular masses are presented, together with their clinical and pathologic findings. Normal Paratesticular Anatomy The paratesticular structures include the tunica vaginalis, epididymis, vestigial remnants, and spermatic cord (Figure 1). The tunica VC 2017 by the American Institute of Ultrasound in Medicine J Ultrasound Med 2017; 00:

2 vaginalis, derived from peritoneal layers, comprises the visceral and parietal layers. The visceral layer encases the testis and epididymis and covers the tunica albuginea. 5,7 The parietal layer is located on the inner scrotal wall. There is a cavity between the visceral and parietal layers where a small quantity of fluid is normally present. The epididymis is a C-shaped structure divided into 3 parts: the head (globus major), the body (corpus), and the tail (globus minor), which has the major function of connecting the testis to the vas deferens. 13 The remnants of the vestigium include the appendix testis (paramesonephric duct remnant), appendix epididymis, paradidymis, and superior and inferior aberrant ductules (mesonephric duct remnants). The spermatic cord, located between the inguinal ring and scrotum, allows the entrance of the structures into the scrotum as the vas deferens, testicular, cremasteric, and deferential arteries, pampiniform plexus, genitofemoral nerve, and lymphatic vessels. 13 Imaging Technique and Radiologic Anatomy Sonography Sonography is the primary imaging technique for the evaluation of paratesticular and testicular tissue, and it is performed with high-resolution broadband linear array transducers. 5 Color Doppler sonography, which allows for vascular assessment, is a component of routine scrotal sonography. 1 The normal scrotal wall is a smooth layer with thickness ranging between 2 and 8 mm, depending on the degree of cremasteric muscle contraction. 5 A small quantity of fluid with no internal echogenicity within the tunica vaginalis is a normal finding. The epididymis is characterized by homogeneous isoechoicto-marginally hyperechoic echogenicity when compared to the testis. 14 The epididymal head typically measures approximately 10 to 12 mm in diameter, the body about 4 mm. 1 The tail is often not well visualized during sonography. The appendix testis, which appears as an Figure 1. Anatomic drawing of testis and paratesticular structures. 2 J Ultrasound Med 2017; 00:00 00

3 Figure 2. Paratesticular lipoma in a 67-year-old man. A, Transverse oblique extended field-of-view sonogram showing a well-defined paratesticular mass (arrows) just lateral to the left testis (LT). RT indicates right testis. B D, Magnetic resonance images of the same patient. Transverse T1-weighted (B), coronal T2-weighted (C), and coronal fat-saturated T2-weighted (D) images show that the lesion is homogeneous and has fat signal intensity in all sequences. Figure 3. Adenomatoid tumor presenting with a palpable mass. A, Color Doppler sonogram showing a small and vascularized lesion (arrows) at the periphery of the testis. B and C, Coronal T2-weighted MRI (B) shows the extratesticular location of the small tumor, which is hypointense compared to the testicular parenchyma and shows homogeneous enhancement on a postcontrast T1-weighted image (C). J Ultrasound Med 2017; 00:

4 ovoid structure near the upper pole of testis, is commonly less than 5 mm in diameter. 5 The appendix epididymis is attached at the epididymal head and may be of the same echogenicity as the epididymis, or less frequently, cystic. 15 The spermatic cord is hyperechoic due to its fat content and covers the tubular structures of the pampiniform plexus, thinwalled straight tubular structure of the testicular artery, and another tubular structure with a relatively thicker wall: the vas deferens. 16 Magnetic Resonance Imaging Magnetic resonance imaging represents a problemsolving diagnostic method for scrotal abnormalities, 10 allowing the differential diagnosis of scrotal lesions by detecting fat, blood products, granulomatous tissue, and fibrosis. 11 T1-weighted images can show fat or methemoglobin content in the lesion, owing to their high signal intensity. 11 The normal tunica albuginea appears as low signal intensity structures covering the testis. 1 The signal intensity of the epididymis is similar to that of the testis on T1- but lower on T2-weighted images. 8 Afluid collection in the scrotum (simple hydrocele) appears as hypointense on T1- and hyperintense on T2-weighted images, similar to fluid located anywhere else in the body. 1 The spermatic cord is of fat signal intensity; the vessels and the vas deferens are seen as low signal intensity tubular structures within it. Figure 4. Adenomatoid tumor with inflammation in a patient presenting with acute scrotum. A, Sonogram showing an extratesticular spherical mass with peripheral hypervascularization. B and C, On sagittal T2-weighted MRI (B), the lesion has a hypointense ring, and it shows ring enhancement after the use of contrast material on a postcontrast T1-weighted image (C). Figure 5. Leiomyoma of the epididymis. A, The whorled pattern, defined as macroscopy of leiomyomas, may be detected and may be helpful for the diagnosis. B, The vascularity is commonly not high in leiomyomas. 4 J Ultrasound Med 2017; 00:00 00

5 Paratesticular Benign Tumors Lipoma Lipoma is the most common tumor of the paratesticular area and spermatic cord, accounting for 45% of all lesions in that region. 2 The most common presentation is an incidentally discovered painless mass. It may occur at any age. Pathologically, lipomas are yellow to orange greasy tumors with an irregular lobular pattern, surrounded by a thin capsule. They are composed of mature fat cells but may include some other elements of mesenchymal tissue,withfibroustissuebeingthemostcommon. On sonography, a typical lipoma is a well-defined homogeneous hyperechoic lesion with brighter linear interfaces inside that separate the fat lobules (Figure 2). Lipomas are typically avascular on Doppler sonography. Sometimes, they may appear to have lower echogenicity than surrounding fat tissue and may mimic nonfatty lesions. On MRI, lipomas appear to have fat signal intensity in all sequences and show suppression on fat-suppressed images. No enhancement occurs after contrast material administration. Adenomatoid Tumor An adenomatoid tumor is the second most common tumor of the paratesticular structures and constitutes 30% of tumors arising in that area. 2 Although the most common presentation is a painless palpable mass, most patients are asymptomatic, and these lesions are discovered during imaging performed for other reasons. 17 Pathologically, an adenomatoid tumor is defined as a hamartomatous benign tumor that originates from the mesothelial cells. 9 They are usually located at the tail of the epididymis but may arise at other parts of the Figure 6. Paratesticular leiomyoma in a 10-year-old boy. A, Longitudinal-oblique sonogram showing a slightly heterogeneous lesion (arrows). B, Elastogram showing that the lesion has increased stiffness when compared to the testis and the other paratesticular tissues. C and D, The lesion has slightly higher signal intensity on a coronal fat-saturated T2-weighted image (C) and shows peripheral enhancement but no enhancement inside on a transverse postcontrast fat-saturated T1-weighted image (D). J Ultrasound Med 2017; 00:

6 epididymis, tunica albuginea, tunica vaginalis, and close to the rete testis. Sonography reveals a solitary oval or round wellcircumscribed homogeneous lesion that is isoechoic or hyperechoic to the testis (Figure 3). On Doppler sonography, only large lesions have demonstrable vascularity. On MRI, they are slightly hypointense relative to the testis on T2-weighted images and usually show poor or absent contrast enhancement on postcontrast T1- weighted images. However, the contrast enhancement does not rule out an adenomatoid tumor, also because exuberant granulation tissue around the tumor has been reported, 11 as in the example presented (Figure 4). Leiomyoma A leiomyoma is a rare benign tumor of mesenchymal origin, composed of smooth muscle. It is the second Figure 7. Angioleiomyoma in a 63-year-old man. A and B, Sonogram (A) showing a lobulated hypoechoic quite well-limited mass (calipers) with vascularity on color Doppler imaging (B). C and D, On T2-weighted MRI (C), the lesion appears as a lobulated hypointense lesion (arrows), which shows peripheral enhancement after contrast material injection on a postcontrast T1-weighted image (D). 6 J Ultrasound Med 2017; 00:00 00

7 Figure 8. Paratesticular angiomyofibroblastoma-like tumor in a 72-year-old patient. A, Grayscale sonogram showing a multiloculated paratesticular mass (asterisk) with echogenic content and a thick wall and septa, displaying vascularization after microbubble contrast material injection. The content is avascular. B, The testis (T) is intact, displaced anteriorly by the paratesticular lesion. C E, Magnetic resonance imaging appearance of the lesion.t1-weighted (C) and T2-weighted (D) images in the sagittal plane show high signal intensity content of the mass with a fluid-fluid level (arrowheads). E, Axial diffusion-weighted image acquired at a b-value of 800 s/mm 2 showing relatively high signal intensity content (asterisk; apparent diffusion coefficient, mm 2 /s), consistent with restriction of water movement. On a histologic examination, fibromyxoid stromal tissue was found, containing vessels of different sizes and cavities with hemorrhagic and jelly material. Figure 9. Epididymal hemangioma in a 19-year-old man. A and B, Grayscale (A) and color Doppler (B) images showing a homogeneous soft tissue mass (arrows) with vascularity inside. C, Histopathologic image of the lesion (hematoxylin-eosin). Figure 10. Paratesticular, perineal, and penile hemangiomas. A and B, Sagittal fat-saturated T2-weighted image (A) showing extensive paratesticular penile and perineal serpiginous high-intensity lesions (arrows), which show contrast enhancement on a postcontrast fat-saturated T1- weighted image (B).T indicated testis. J Ultrasound Med 2017; 00:

8 most common tumor of the epididymis (6%). 2 It commonly presents as a nontender slowly growing mass. Pathologically, leiomyomas are well circumscribed lesions with a gray-white fibrous capsule and a whorled pattern inside. The tumor is composed of smooth muscle cells arranged in interlacing bundles with an admixture of fibrous and hyalinized connective tissue. 18 On sonography, leiomyomas are well-defined solid lesions of variable echogenicity. The whirling pattern maybedemonstrable(figure5).centralnecrosis,a cystic component, or punctate calcifications may be observed. Vascularity may be detected on Doppler sonography. The MRI appearance of paratesticular leiomyomas has not been fully described. The only MRI example of paratesticular leiomyoma in our series belongs to a 10-year-old child (Figure 6). The lesion was hyperintense with respect to the testis on T2-weighted images, and after contrast material injection, only peripheral contrast enhancement was observed. Angioleiomyoma An angioleiomyoma of the paratesticular area is extremely rare, with only a few case reports in the literature. 19,20 Pathologically, the lesion has been reported as a circumscribed mass with a smooth muscle capsule, edematous stroma, small vessels, and numerous cystically dilated ectatic vessels. 19 On sonography, angioleiomyomas are solid welldefined tumors with low echogenicity (Figure 7). Vascularity is abundant on Doppler sonography; however, this finding is not helpful for a specific diagnosis, or it even Figure 11. Papillary cystadenoma in von Hippel-Lindau disease. A and B, The epididymal head is enlarged and contains multiple cystic lesions separated by solid hypervascular areas. 8 J Ultrasound Med 2017; 00:00 00

9 Figure 12. Fibrous pseudotumors in a 59-year-old man. A D, Grayscale sonograms (A and B), color Doppler image (C), and elastogram (D) showing multifocal spherical well-defined lesions (arrows) just beneath the testis (T) and in various parts of the inner scrotal wall, attached to the tunica. Little vascularity can be seen inside the lesion on the color Doppler image. The elastogram shows that the lesions have relatively higher stiffness than the testis. E, Coronal T2-weighted MRI showing the typical very low signal intensity of the lesions (arrows). F and G, The lesions show enhancement after the use of contrast material in coronal and sagittal postcontrast fat-saturated T1-weighted images. J Ultrasound Med 2017; 00:

10 may be misleading, since it may suggest malignancy or, if the lesion is adjacent to the epididymis, epididymitis. Magnetic resonance imaging may be helpful in showing the tissue components; however, a differential diagnosis from a malignant tumor may not be possible. The myomatous components may show low signal intensity on T2-weighted images. After the use of contrast material, the lesion shows enhancement. Angiomyofibroblastoma-Like Tumor An angiomyofibroblastoma is a tumor that occurs in the pelvis, genital tract, vulva, or perineum of women. An angiomyofibroblastoma-like tumor is the male counterpart. It is observed in elderly men as a slowly growing asymptomatic lesion. Only sporadic case Figure 13. Polyorchidism in a 32-year-old man. A, Transvers oblique extended field-of-view sonogram of the scrotum showing the right testis (RT), left testis (LT), and supernumerary testis (arrows) just lateral to the left testis. The supernumerary testis has almost the same echo texture as the original testes; however, it has a slight hypoechoic appearance. B, Power Doppler image showing that the supernumerary testis (arrows) has low vascularity. reports of angiomyofibroblastoma-like tumors exist in the literature. 21,22 Histopathologically, the tumor is composed of spindle-shaped cells arranged around numerous small to medium-sized vessels in abundant myxoid stroma and dense collagen fibers. On immunohistochemical staining, the spindle-shaped cells are positive for CD34 but negative for desmin, smooth muscle actin, and S-100 protein. These findings have been reported to be characteristic of angiomyofibroblastoma-like tumors. 22 On sonography, the lesion appearance is variable. We observed a case presenting with echogenic avascular content corresponding to fibromyxoid stromal tissue and cavities with hemorrhagic and jelly material. The thick wall and septa showed vascularization after microbubble contrast material injection. On MRI, fluid-fluid levels and hemorrhage were detected, and peripherally enhancing solid areas were observed (Figure 8). Hemangioma Paratesticular hemangiomas may arise from the spermatic cord or scrotal wall, and they constitute less than 1% of all hemangiomas. 2 They usually present in infants, occasionally in later childhood or adolescence. Most patients are asymptomatic; however, dull aching pain, heaviness, bleeding, and ulceration have been reported. 2 Pathologically, numerous vascular spaces lined with benign epithelial cells are detected in the lesions. The lesions may be characterized as capillary, cavernous, or arteriovenous. 2 Imaging features vary depending on the histopathologic type of the hemangioma and the presence of drainage veins. The tortuous vessels inside a cavernous or arteriovenous hemangioma may mimic a varicocele on sonography and Doppler imaging. The capillary type of hemangioma presents as a soft tissue mass with posterior acoustic enhancement (Figure 9). 23 Magnetic resonance imaging shows very high signal intensity on T2-weighted images. The lesion and serpiginous vessels show enhancement after contrast material injection (Figure 10). Papillary Cystadenoma A cystadenoma or papillary cystadenoma is a lesion of the epididymis that may occur sporadically (40%) or as a component of von Hippel-Lindau disease. 2 They may be bilateral in up to one-third of cases, and bilateral lesions are strongly associated with von Hippel-Lindau disease J Ultrasound Med 2017; 00:00 00

11 Pathologically, they are benign multicystic lesions with 2 common findings: ectasia of efferent ducts and papillary formations. Cysts are filled with a colloidlike secretion. On sonography, cystadenomas appear as predominantly solid lesions with cystic spaces or as cystic lesions with papillary projections inside (Figure 11). Diagnostic criteria have been defined for conservative management of cystadenomas, which include a predominantly solid epididymal mass larger than mm, occurrence in von Hippel-Lindau disease, and depiction of slow growth. 2 Paratesticular Non-neoplastic Masses Fibrous Pseudotumor This tumor is the third most common paratesticular mass after a lipoma and an adenomatoid tumor. A fibrous pseudotumor is not a true neoplasm but is a mass of fibrous tissue proliferation, which occurs in the tunica vaginalis of the scrotum. It may attain large diameters and may be multifocal. Hydrocele is present in nearly half of the patients, and at least 30% of them have a history of epididymo-orchitis. 11 Pathologic analysis shows dense fibrous tissue with interspersed fibroblasts and mixed inflammatory cells. A nodular type and a diffuse type have been defined on the basis of the gross appearance; however, these types also may coexist. 7 On sonography, fibrous pseudotumors are homogeneous lesions with solid tissue echogenicity. (Figure 12). Doppler sonography may rarely show internal vascularity. 7 Magnetic resonance imaging may provide the diagnosis, since these lesions have low signal intensity on both T2- and T1-weighted images. They show Figure 14. Some of various presentations of epididymal cysts (arrows). A, The most common, typical presentation, as a millimetric anechoic unilocular lesion. B, Multifocal form. C, Presentation as a large unilocular cystic lesion with echogenic reflections inside, which is impossible to differentiate from a spermatocele. D, Multilocular cystic type. J Ultrasound Med 2017; 00:

12 Figure 15. Spermatocele: 2 different cases of epididymal cystic lesions. A, Huge anechoic mass (arrows) in the epididymis of a postvasectomy patient. B, Thick but smooth-walled cystic lesion (arrow) with high-level echoes inside that has been shown to float during real-time imaging. However, the lesion was also shown to have immobile impacted content (asterisk). T indicates testis. The testis of the in B has incidental testicular microlithiasis. Figure 17. Spermatic cord lipomatosis. A C, Two different cases with (A and B) and without (C) hydrocele. Longitudinal extended field-ofview sonogram (A) and coronal T2-weighted image (B) show an asymmetrically thickened left spermatic cord (arrows). In the second case (C), longitudinal extended field-of-view sonogram shows the thickened cord and the hydrocele (asterisk); e indicates epididymis; and T, testis. Figure 16. Spermatic cord cyst in a 66-year-old man. Longitudinal extended field-of-view sonogram showing an anechoic cystic lesion in the spermatic cord (arrows); e indicates epididymis; and T, testis. 12 J Ultrasound Med 2017; 00:00 00

13 Figure 18. Rhabdomyosarcoma in a 10-year-old boy. A C, Sonogram (A), elastogram (B), and Doppler image (C) showing a prominently hypoechoic lesion with high vascularity and increased stiffness. D, The lesion is isointense when compared to the testis on T2-weighted MRI (arrow). E, Coronal fat-saturated postcontrast T1-weighted MRI showing contrast enhancement (arrow) after the use of contrast material. J Ultrasound Med 2017; 00:

14 uniform persistent enhancement after contrast material administration. 11 Polyorchidism Polyorchidism is an anomaly that occurs possibly as a result of division of the genital ridge by peritoneal bands. 2,24 The supernumerary testis may share the vas deferens and epididymis of the ipsilateral testis, or it may have its own epididymis and vas deferens. In some conditions, the supernumerary testis has no epididymis and vas deferens, and no connection may be found with the originally developed testis. Polyorchidism presents as a painless palpable mass; the risk of torsion and tumor development are known to exist. 11 On sonography, the supernumerary testis may be in the scrotum or in the inguinal canal with or without a connection to the testis. It is commonly smaller than normal and is hypoechoic to the original testis (Figure 13). On Doppler sonography, the vascularity is commonly less than the original. The mediastinum testis and shared epididymis may be shown, or a supernumerary epididymis may be detected. On MRI, the signal intensity of the supernumerary testis has been reported to be almost identical to that of the normal testis. A hypointense rim encircling the supernumerary testis that corresponds to the tunica albuginea may be shown, a finding that is often helpful for recognizing the lesion as a testis, thus differentiating it from other lesions. Figure 19. Well-differentiated liposarcoma in a 73-year-old man. A and B, A paratesticular solid homogeneous mass on sonography (A) has vascularity inside, as detected by Doppler imaging (B). C and D, Transverse T1-weighted (C) and T2-weighted (D) MRI showing a solid highly cellular homogeneous lesion (arrows). E and F, Transverse(E) and sagittal (F) postcontrast fat-saturated T1-weighted images showing prominent contrast enhancement of the tumor. 14 J Ultrasound Med 2017; 00:00 00

15 Polyorchidism is conservatively managed, but follow-up is suggested. Surgery may be necessary in case of complications. Splenogonadal Fusion This condition is a rare congenital anomaly due to fusion of splenic tissue to the vas deferens or gonad. It most commonly occurs on the left side and may arise together with cryptochidism, an inguinal hernia, and other anomalies of the face, limbs, and heart. On sonography, splenogonadal fusion is seen as a mass attached to the testis with similar or lower echogenicity compared to the testis, and it may have an imaging appearance similar to that of polyorchidism. 11,25 Figure 20. Myxoid liposarcoma of the right spermatic cord in a 73- year-old man. A, Sagittal extended field-of-view image of the left hemiscrotum showing the testis (T) and a solid heterogeneous mass (arrows) separate from it. The lesion had a markedly hyperintense signal on T2-weighted MRI, suggesting a cyst (not shown). However, it was clearly solid on sonography, with internal vessels visible on color Doppler imaging (B). Spermatocele and Epididymal Cyst These are the most commonly encountered epididymal lesions that occur secondary to obstruction of a ductule and retention of fluid inside. 5,6 Patients present with a painless soft mass that can be palpated beneath the testis. Spermatoceles include spermatozoa or spermatids, but epididymal cysts do not. On sonography, an epididymal cyst is a thin-walled lesion anechoic lesion. Spermatoceles commonly have echogenic floating reflections inside, which may sometimes show inspissation. However, an epididymal cyst also may include echogenic reflections inside, and differentiation of these lesions is commonly not possible. Epididymal cysts and spermatoceles may be present in millimetric to huge sizes and may show a variety of appearances on sonography as unilocular, multilocular, septated, single, or multiple (Figures 14 and 15). Sperm Granuloma A sperm granuloma is a lesion that occurs as a foreign body reaction in postvasectomy patients. On sonography, sperm granulomas have been described as wellcircumscribed hypoechoic heterogeneous lesions found within the epididymis. 26 Spermatic Cord Cyst A spermatic cord cyst is a developmental anomaly of the processus vaginalis, in which both sides of the processus vaginalis are closed with a potential space remaining between the two inguinal rings. It appears as a loculated fluid-filled tubular structure (Figure 16). Spermatic Cord Lipomatosis This anomaly is a benign condition of the spermatic cord, which may be observed as isolated or together with persistent hydrocele. The common presentation is a soft lump in the groin, which may mimic an inguinal hernia. On sonography, the spermatic cord is seen as thickened and heterogeneous (Figure 17). Magnetic resonance imaging is helpful for the diagnosis of lipomatosis by depiction of fat content. Contrast-enhanced series would be helpful to disclose a fat-containing malignant tumor. J Ultrasound Med 2017; 00:

16 Paratesticular Malignant Tumors Rhabdomyosarcoma This tumor is the most common sarcoma of the paratesticular tissue in childhood, with peaks of presentation at 5and16years. 27 Pathologically, the tumor has embryonal, alveolar, and pleomorphic subtypes. Macroscopically, the tumor appears as an encapsulated gray-white mass with areas of hemorrhage, cystic degeneration, or both. 9 On imaging, a rhabdomyosarcoma may be homogeneous when detected early (Figure 18); however, it commonly presents as a large heterogeneous tumor with cystic/necrotic components. Figure 21. Dedifferentiated liposarcoma in a 74-year-old man. A, Computed tomograms in correlation with the pathologic macroscopy showing the solid component, fat component, and gross calcification of the tumor. B and C, Coronal reformatted CT (B) and coronal T2-weighted MRI (C) of the same patient showing the tumor components together. 16 J Ultrasound Med 2017; 00:00 00

17 Liposarcoma A liposarcoma is the most common paratesticular malignant tumor in the elderly Most are detected in the fifth or sixth decade, and the common presentation is a slowly growing nontender mass. Figure 22. Leiomyosarcoma of the spermatic cord in a 78-year-old man. A C, Longitudinal extended field-of-view (A) and transverse (B) sonograms and power Doppler image (C) showing a large solid hypervascular mass (arrows) with cystic/necrotic components located at the distal part of the spermatic cord. J Ultrasound Med 2017; 00:

18 A liposarcoma is a soft tissue sarcoma of adipocytic origin, with subtypes including well-differentiated liposarcoma, an atypical lipomatous tumor, dedifferentiated liposarcoma, and myxoid/round cell liposarcoma. The other subtypes include pleomorphic liposarcoma and mixed liposarcoma. 30 On sonography, the echogenicity of a liposarcoma varies from a solid hypoechoic tumor (Figure 19) to a lesion containing highly echogenic areas of fat (Figure 20). Doppler sonography commonly shows high vascularity inside the lesion. The gross or macroscopic fat component of the lesion may sometimes be demonstrable by CT or MRI, which makes the diagnosis easy. The solid parts commonly enhance intensely. The lesion may have gross calcification (Figure 21). Leiomyosarcoma A leiomyosarcoma is a rare malignant tumor of smooth muscle origin, mostly located at the spermatic cord. The most frequent time of diagnosis is the sixth decade. 16 Pathologically, a leiomyosarcoma is a firm wellcircumscribed whitish lobulated mass with central necrosis, hemorrhage, or both. On sonography, leiomyosarcomas appear as welldefined masses with variable echogenicity that may show hemorrhage, necrosis, or cystic degeneration. Solid components are frequently hypervascular on Doppler sonography (Figure 22). 16 On MRI, leiomyosarcomas appear as solid lesions of variable intensity on T2- weighted images. After contrast material injection, the solid parts show marked enhancement (Figure 23). Figure 23. Leiomyosarcoma of the spermatic cord in a 67-year-old man. A C, Computed tomogram (A) and fat-saturated T2-weighted (B) and postcontrast fat-saturated T1-weighted (C) MRI showing a huge mass at the spermatic cord-inguinal area (arrows) with central necrosis (asterisks). D, Macroscopic specimen from the same patient. 18 J Ultrasound Med 2017; 00:00 00

19 Undifferentiated Sarcoma An undifferentiated sarcoma, formerly known as a malignant fibrous histiocytoma, is an uncommon malignant mesenchymal tumor of the paratesticular area. 9 It is a rapidly growing tumor, commonly presenting in the sixth decade. Pathologically, the tumor is commonly large with hemorrhage and necrosis. Microscopically, pleomorphic spindle, polygonal, and multinucleated giant tumor cells and atypical mitoses are found. Myxoid and inflammatory changes may be found. 31 Imaging features of undifferentiated sarcomas are nonspecific. They may attain great sizes at the time of presentation and are heterogeneous in structure with cystic/necrotic areas and calcifications inside a solid lesion. A malignant mesothelioma is a malignant tumor originating from the tunica vaginalis. 9 The presentation age has a wide range between 6 and 91 years, most commonly between 55 and 75 years. 32 Ahistoryofasbestos exposure is a well-known risk factor, which has been shown to exist in 12.5% to 40% of patients. 33 Pathologic analysis shows a paratesticular tumor that typically appears as multiple firm tan-to-white nodules or papillary projections on the internal surface of the hydrocele. 34 Infiltration into the subtunical connective tissue or the testis occurs in half of the cases. Histologically, malignant mesotheliomas have been classified as epithelial, biphasic, and sarcomatoid subtypes. On sonography, simple or echogenic hydrocele is typically present, and also in some cases, it may be the only recognizable finding. The most common appearances of this tumor are single or multiple nodules arising from the surface of the tunica albuginea, of various diameters. Rarely, they may be seen as hypoechoic solid lesions attached to the testis or the epididymis. 33,34 Figure 24. Mesothelioma of uncertain malignant potential in a 58-year-old man with a palpable mass. A, Sagittal image of the right testis (RT) showing a small amount of fluid in the tunica vaginalis and a small solid nodule (arrow) at the upper part of the cavity. B, Axial view showing another nodule, which was not surrounded by fluid (arrow). C, Axial image below the lower pole of the testis showing 2 additional nodules with a small quantity of fluid (arrows). D, Surgical specimen showing the nodules on the surface of the tunica vaginalis. LT indicates left testis. J Ultrasound Med 2017; 00:

20 Figure 25. Metastasis of renal carcinoma to the spermatic cord in a 57-year-old man. A, Longitudinal extended field-of-view sonogram showing a solid hypoechoic tumor at the spermatic cord location (arrows). B, Computed tomograms showing the contrast-enhanced solid lesion. Figure 26. Melanoma metastasis in a 67-year-old man. Coronal reformatted CT showing a mass in the right proximal spermatic cord (long arrow) as well as metastatic lymph nodes in both inguinal areas (short arrows). 20 J Ultrasound Med 2017; 00:00 00

21 Large lesions are hypervascular on color Doppler sonography (Figure 24). Metastases Metastases to the paratesticular tissues may occur as a result of local invasion of a testicular tumor or as implants from distant primaries. The prostate, kidney, stomach, colon, ileum carcinoid, and pancreas, are the most common origins, in decreasing order of frequency. 9 In patients with a patent peritoneovaginal canal, drop metastases to the scrotum from intraperitoneal tumors may be encountered. On sonography, local invasion of paratesticular structures by the testicular tumor may be easily Figure 27. Lymphoma (natural killer T-cell type) infiltration of the epididymis in a 34-year-old man. A, On sonography, the epididymis is enlarged and more hypoechoic than normal (long arrow). The testis is shown as infiltrated as well, through the mediastinum (short arrows). B, On Doppler imaging, the infiltrated epididymis has increased vascularity. shown. Distant metastatic lesions are seen as solid irregular lesions, with nonspecific imaging features. However, most of them are accompanied by multiple metastatic lesions at the other sites of the body (Figures 25 and 26). Hematopoietic Malignancies Lymphoma/leukemia and plasmocytoma may involve the paratesticular tissues, either alone or in combination with involvement of the testis. On sonography, hematopoietic paratesticular tumors appear as hypoechoic homogeneous infiltrative or permeative lesions. Commonly, the vessels are not distorted by the infiltration, which may help differentiate Figure 28. Multiple soft tissue plasmocytomas (soft tissue myelomas) in a 31-year-old man. A, Transverse extended field-of-view sonogram showing bilateral testicular hypoechoic infiltrations (short arrows) and also infiltration of the left epididymis (long arrow). B, Transverse oblique sonogram of the left hemiscrotum showing the epididymal involvement better (arrow). This patient also had multiple subcutaneous myeloma lesions (not shown). J Ultrasound Med 2017; 00:

22 them from other solid firmly growing lesions (Figures 27 and 28). 35 Conclusions Paratesticular masses include a variety of neoplastic and non-neoplastic lesions. Sonography is the method of choice for detection and determination of the locations of the lesions. Some of the lesions may readily be diagnosed on the basis of sonographic findings alone, but additional imaging may be necessary for the diagnosis or to narrow the differential diagnoses. Magnetic resonance imaging is the most suitable imaging method for additional investigation. Differentiation of malignant and benign paratesticular masses from each other may be provided by sonography, MRI, or a combination most of the time. However, overlap of the imaging findings of benign and malignant tumors may always be possible and should be kept in mind. Solid lesions commonly necessitate surgery for treatment, whereas a nonsurgical approach and follow-up may be the choice in purely cystic lesions or lesions composed of pure fat. References 1. Woodward PJ, Schwab CM, Sesterhenn IA. Extratesticular scrotal masses: radiologic-pathologic correlation. Radiographics 2003; 23: Akbar SA, Sayyed TA, Jafri SZ, Hasteh F, Neill JS. Multimodality imaging of paratesticular neoplasms and their rare mimics. Radiographics 2003; 23: Khoubehi B, Mishra V, Ali M, Motiwala H, Karim O. Adult paratesticular tumours. BJU Int 2002; 90: Smart JM, Jackson EK, Redman SL, Rutherford EE, Dewbury KC. Ultrasound findings of masses of the paratesticular space. Clin Radiol 2008; 63: Dogra VS, Gottlieb RH, Oka M, Rubens DJ. Sonography of the scrotum. Radiology 2003; 227: Ragheb D, Higgins JL Jr. Ultrasonography of the scrotum: technique, anatomy, and pathologic entities. JUltrasoundMed2002; 21: Garriga V, Serrano A, Marin A, Medrano S, Roson N, Pruna X. US of the tunica vaginalis testis: anatomic relationships and pathologic conditions. Radiographics 2009; 29: Park SB, Lee WC, Kim JK, et al. Imaging features of benign solid testicular and paratesticular lesions. Eur Radiol 2011; 21: Davis CJ, Woodward PJ, Dehner LP, et al. Tumours of paratesticular structures. In: Pathology and Genetics of Tumours of the Urinary System and Male Genital Organs. Lyon, France: IARC Press; 2004: Cramer BM, Schlegel EA, Thueroff JW. MR imaging in the differential diagnosis of scrotal and testicular disease. Radiographics 1991; 11: Cassidy FH, Ishioka KM, McMahon CJ, et al. MR imaging of scrotal tumors and pseudotumors. Radiographics 2010; 30: Mohrs OK, Thoms H, Egner T, et al. MRI of patients with suspected scrotal or testicular lesions: diagnostic value in daily practice. AJR Am J Roentgenol 2012; 199: H ormann M, Balassy C, Philipp MO, Pumberger W. Imaging of the scrotum in children. Eur Radiol 2004; 14: Bhatt S, Rubens DJ, Dogra VS. Sonography of benign intrascrotal lesions. Ultrasound Q 2006; 22: Kantarci F, Ozer H, Adaletli I, Mihmanli I. Cystic appendix epididymis: a sonomorphologic study. Surg Radiol Anat 2005; 27: Secil M, Kefi A, Gulbahar F, Aslan G, Tuna B, Yorukoglu K. Sonographic features of spermatic cord leiomyosarcoma. JUltrasoundMed 2004; 23: Kolgesiz AI, Kantarci F, Kadioglu A, Mihmanli I. Adenomatoid tumor of the tunica vaginalis testis: a special maneuver in diagnosis by ultrasonography. J Ultrasound Med 2003; 22: Ozden O, Orhan D, Karnak I. Epididymal leiomyoma: an unusual intrascrotal tumor in a child. J Pediatr Surg 2009; 44:e5 e Ghei M, Arun B, Maraj BH, Miller RA, Nathan S. Case report: angioleiomyoma of the spermatic cord a rare scrotal mass. Int Urol Nephrol 2005; 37: Del Sordo R, Leite S, Petroni PA, Sidoni A. Paratesticular angioleiomyoma with cytological atypia. Int J Urol 2008; 15: Lee SH, Yang JW, Do JM, et al. Angiomyofibroblastoma-like tumor of the scrotum. Korean J Urol 2010; 51: Maruyama M, Yoshizako T, Kitagaki H, Araki A, Igawa M. Magnetic resonance imaging features of angiomyofibroblastoma-like tumor of the scrotum with pathologic correlates. Clin Imaging 2012; 36: Stewart VR, Sriprasad S, Pomplun S, Walsh K, Sidhu PS. Sonographic features of a spermatic cord capillary hemangioma. J Ultrasound Med 2007; 26: Amodio JB, Maybody M, Slowotsky C, Fried K, Foresto C. Polyorchidism: report of 3 cases and review of the literature. JUltrasoundMed 2004; 23: Stewart VR, Sellars ME, Somers S, Muir GH, Sidhu PS. Splenogonadal fusion: B-mode and color Doppler sonographic appearances. J Ultrasound Med 2004; 23: Oh C, Nisenbaum HL, Langer J, Rowling S, Van Arsdalen KN. Sonographic demonstration, including color Doppler imaging, of recurrent sperm granuloma. J Ultrasound Med 2000; 19: Rodrıguez D, Barrisford GW, Sanchez A, Preston MA, Kreydin EI, Olumi AF. Primary spermatic cord tumors: disease characteristics, prognostic factors, and treatment outcomes. Urol Oncol 2014; 32: 52.e19 52.e J Ultrasound Med 2017; 00:00 00

23 28. Coleman J, Brennan MF, Alektiar K, Russo P. Adult spermatic cord sarcomas: management and results. Ann Surg Oncol 2003; 10: Abete L, Simonato A, Toncini C, Carmignani G, Derchi LE. Myxoid liposarcoma of the spermatic cord: US and MR imaging findings. J Clin Ultrasound 2014; 42: Fletcher CDM, Unni KK, Mertens F (eds). World Health Organization Classification of Tumours: Pathology and Genetics of Tumours of Soft Tissue and Bone. Lyon, France: IARC Press; Fisher C, Montgomery EA, Thway K. Biopsy Interpretation of Soft Tissue Tumors. Philadelphia, PA: Wolters Kluwer Lippincott; 2011: Perez-Ordonez B, Srigley JR. Mesothelial lesions of the paratesticular region. Semin Diagn Pathol 2000; 17: Boyum J, Wasserman NF. Malignant mesothelioma of the tunica vaginalis testis: a case illustrating Doppler color flow imaging and its potential for preoperative diagnosis. J Ultrasound Med 2008; 27: Bertolotto M, Boulay-Coletta I, Butini R, et al. Imaging of mesothelioma of tunica vaginalis testis. Eur Radiol 2016; 23: Bertolotto M, Borsato A, Derchi LE. Lymphoma of the spermatic cord: sonographic appearance. J Clin Ultrasound 2014; 42: J Ultrasound Med 2017; 00: