Sonographic appearances of benign soft tissue lumps and bumps. Hints and tips for differential diagnosis.

Transcription

1 Sonographic appearances of benign soft tissue lumps and bumps. Hints and tips for differential diagnosis. Award: Certificate of Merit Poster No.: C-0244 Congress: ECR 2016 Type: Educational Exhibit Authors: I. Katsimilis, C. Lord, R. Kulanthaivelu, V. T. Skiadas; Southampton/UK Keywords: Tissue characterisation, Diagnostic procedure, Ultrasound, Musculoskeletal soft tissue DOI: /ecr2016/C-0244 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 35

2 Learning objectives The purpose of this study is to present the sonographic appearances of a variety of benign soft tissue masses, focusing on specific sonographic features narrowing the differential diagnosis. Page 2 of 35

3 Background In every day practise a number of patients present with various symptomatic or asymptomatic lumps and bumps throughout the body. Ultrasound has emerged as a useful imaging tool to provide clinically vital information for the assessment of a wide range of soft tissue pathologic conditions. US is an excellent imaging modality to determine the nature of a mass lesion (cystic or solid) and anatomic relation to adjacent structures. Masses can be also characterized in terms of their size, shape, number, echotexture, and vascularity with power and colour Doppler US. Ultrasound's dynamic nature can demonstrate compressibility of the lesion and relation with adjacent moving structures, such as tendons. In our pictorial assay we present the majority of common benign lesions, while keeping in mind that malignant lesions can also be assessed with ultrasound. Page 3 of 35

4 Findings and procedure details We present our one-year experience with almost 400 patients, with benign soft tissue lesions. Patients usually present with a visible, palpable, painful or painless lump. Lipoma: Lipomata are the most common soft tissue masses encountered. Usually their location is subcutaneous ( Fig. 1 on page 9 ), however intramuscular ( Fig. 2 on page 9, Fig. 3 on page 9, Fig. 4 on page 10 ) and intrafascial ( Fig. 5 on page 11 ) lipomas are not infrequent. They can be seen in various locations, can be solitary as well as multiple and are usually painless. They are commonly encapsulated with well-defined borders, however a significant proportion has ill-defined borders. On ultrasound they are usually slightly hyperechoic in comparison with the adjacent fat, however echogenicity varies and iso- and hypoechoic patterns are seen depending on the degree of connective tissue and other reflective interfaces within the mass. Most lipomas are avascular on Doppler imaging a finding that enhances the confidence in characterizing them as a benign mass. Subcutaneous lipomata are usually compressible with the probe, however deep seated lipomas can be non-compressible, and in some cases MRI is necessary for further assessment, especially for sizable masses larger than 10 cm ( Fig. 6 on page 12 ). Cystic lesions: Cystic lesions like ganglia, synovial cysts, sebaceous cysts, epidermal cysts are the second most common. Cysts lined by synovial tissue are often found in characteristic locations and may communicate with a joint space. 1. Baker's cyst: In particular Baker's cysts ( Fig. 7 on page 13 ) are located in the medial aspect of the popliteal fossa and appear on ultrasound as anechoic, well-defined cystic masses with smooth and rounded margins and often with obvious origin between the medial head of the gastrocnemius and the semimembranosus tendon and a communicating neck with the knee joint. Complicated Baker's cyst (e.g., prior haemorrhage or synovitis) may demonstrate heterogeneous echotexture secondary to debris, thickened synovium, septations and echogenic loose bodies. Ruptured Baker's cysts demonstrate an irregular usually pointed caudal margin with hypoechoic fluid tracking along the distal soft tissues. Usually the cyst itself is not demonstrated and only the distally tracking fluid is the only evidence of a ruptured Baker's cyst. Page 4 of 35

5 2. 3. Ganglion cysts: Ganglion cysts can occur at various locations as the wrist, hand, ankle, foot, elbow, knee, shoulder, hip. The wrist and hand are more commonly affected. The dorsal wrist ganglion is the most common hand soft tissue mass and is located superficially to the scapholunate ligament. Volar ganglion cysts of the wrist are commonly located at the radial aspect of the wrist, originating usually from the scaphotrapezium joint and extending between the radial artery and the flexor carpi radialis tendon ( Fig. 8 on page 14 ). Typical ultrasound features are these of an anechoic or hypoechoic well-defined, lobulated mass, oval or round in shape. Quite often an anechoic neck is seen leading to the joint space. Tendon sheath ganglion cysts ( Fig. 9 on page 15 ) are mobile stiff masses arising from the visceral layer of the tendon sheath. Sebaceous cysts: Sebaceous cysts ( Fig. 10 on page 15 ) appear as subcutaneous ovoid or spherical hypoechoic masses with scattered internal echoes and posterior acoustic enhancement. A small superficial extension into the dermis corresponds to their small opening to the skin. The internal echogenicity may vary depending on the hydration of keratin, protein composition and microcalcifications. They lack internal vascularity on Doppler imaging. Inflammatory lesions: Inflammatory lesions such as bursitis, foreign body granulomata, abscesses and joint effusion related to sepsis or synovitis due to inflammatory arthropathies, enlarged lymph nodes, are also common abnormalities that can present as soft tissue swellings Inflammed bursae: Bursitis usually presents as a localized fluid collection and synovial wall hypertrophy within a distended bursa that my show realtime fluctuation with transducer probe pressure and posterior acoustic enhancement. Soft tissue hyperaemia is often recognized with Doppler studies as accompanying feature. Increased wall thickness with synovial hypertrophy is seen with increased vascularity confirmed in Doppler. Septations and echogenic content can also be seen. Typical cases are Olecranon bursitis ( Fig. 11 on page 16), bicipitoradial bursitis ( Fig. 12 on page 16, Fig. 13 on page 16 ) and prepatellar bursitis ( Fig. 14 on page 17 ) that present as swellings over the olecranon, antecubital fossa and the lower half of the patella. Foreign bodies granulommata: Foreign bodies ( Fig. 15 on page 17 ) usually present as reflective structures, with posterior acoustic shadowing or reverberation artefact, depending on their nature. Usually they are surrounded by a hypoechoic halo representing reactive oedema and granulation tissue. Hypervascularity is seen on Doppler imaging. If missed they can result in granuloma formation, secondary soft tissue infection, with abscess formation, fistula, purulent tenosynovitis or even septic arthritis. Abscesses: Abscesses ( Fig. 16 on page 18 ) are irregular, commonly hypoechoic collections, containing a variable amount of echogenic debris Page 5 of 35

6 (pus). Fluid -fluid levels can be seen. Depending on their content they can appear echogenic, but a slight pressure with the probe displaces the echogenic fluid and confirms their cystic nature. Doppler imaging shows increased blood flow within the abscess wall and the surrounding tissues. US guided aspiration may be required both for diagnosis and to aid the correct choice of antimicrobial therapy. Enlarged lymph nodes: Enlarged lymph nodes ( Fig. 17 on page 18 ) can present like superficial lumps. They usually appear as oval solid hypoechoic masses with a central hyperechoic hilum and hilar vascularity demonstrated in Doppler. A less well-defined differentiation between the hypoechoic cortex and the hyperechoic hilum, increase in the short axis and loss of the characteristic flow pattern, can be seen in high inflammatory states, lymphomas or other neoplastic infiltration. In such cases reliable differentiation cannot be obtained with ultrasound. Joint effusion: Joint effusions related to infection ( Fig. 18 on page 19 ) or inflammatory arthropathies, ( Fig. 19 on page 20, Fig. 20 on page 21 ) can appear as localised swelling and can be easily detected by US as fluid-distended recesses at the periphery of the joints. Gouty tophi: Gouty tophi ( Fig. 21 on page 22 ) are soft tissue conglomerates of uric acid crystals that can develop in different areas of the body. The hand, the foot and the elbow are commonly involved. At US examination they appear as heterogeneous masses containing hypoechoic areas related to the chalky liquid material surrounded by hyperechoic tissue. They do not show significant vascularity. Rarely calcific deposits are detected within the mass with or without posterior acoustic attenuation. Solid lesions: Pilomatrixoma: Pilomatrixomata ( Fig. 22 on page 22 ) are rare benign superficial tumours of the hair follicles. On US they present as hyperechoic masses with posterior acoustic shadowing, reflecting internal calcific debris or ossification. The amount of calcification may vary. A hypoechoic rim may be seen. On Doppler examination peripheral flow is often found. Fibromatosis: Plantar fibromatosis ( Fig. 23 on page 23 ) is a localized nodular fibrous proliferation of the plantar fascia that presents as a painful or slightly painless hypoechoic subcutaneous nodule at the medial apsect of the midfoot. Symptoms may be aggravated by walking. Palmar fibromatosis (also referred as Dupuytren's disease), present as nodular hypoechoic thickenings of the palmar aponeurosis located between the skin and the flexor tendons. They can progress to fibrous cords that result in flexion contracture. Fibrous nodules have sharp margins and are hypoechoic without any internal vascularity ( Fig. 24 on page 23 ). Morton's neuroma: Morton's neuromas ( Fig. 25 on page 24 ) are pseudotumours, classically occurring in middle aged women and seen at the second and third intermetatarsal spaces at the level of the metatarsal Page 6 of 35

7 4. heads. On ultrasound is characterized by a poorly reflective hypoechoic, non-compressible mass within the web space. Interdigital palpation and dynamic manoeuvres like Moulder's click can obviate the diagnosis. Neurogenic tumours: Neurogenic tumours ( Fig. 26 on page 25, Fig. 27 on page 25, Fig. 28 on page 25 ), can also present like focal subcutaneous swellings, most ofetn of the extremities. The two main histological types are schwannomas and neurofibromas. The US diagnosis of these tumors is based on the demonstration of a solid hypoechoic mass in direct continuity with a nerve at its proximal and distal ends (tail sign). They maybe exhibit acoustic enhancement and variable blood flow on Doppler imaging. Schwannomas are usually eccentric to the nerve axis, while neurofibromas are more concentric and intimately associated with the parent nerve. Intratumoral cystic changes related to accumulation of myxoid matrix can be seen. Post traumatic swelling: Haematoma: Haematoma ( Fig. 29 on page 26, Fig. 30 on page 26, Fig. 31 on page 27 ) appearances depend on the time interval between the traumatic event and scanning. It can vary from an echogenic mass consisting of a solid blood clot to a completely anechoic structure (completely liquefied haematoma). A very useful feature of haematomata is the complete abscence of interanal blood flow, unless there is still active bleeding at the time of teh scan. Clinical history is very important for the diagnosis (injury, blood thinning medication), since sometimes the appearances can be identical to an abscess and further imaging or aspiration may be requested. Morel-Lavallee: Morel-Lavallee lesion ( Fig. 32 on page 28 ) is the sequalae of a post-traumatic closed degloving injury, between the subcutaneous fat and the underlying deep muscle fascia, located over the lateral aspect of the hip. On US it presents as a hypo-anechoic fluid collection, that is compressible, with lack of internal flow and my contain globules of echogenic fat. In these cases the clinical history can be very helpful. Fat necrosis: In traumatic settings following a contusion, fat necrosis may arise ( Fig. 33 on page 28 ), which appears as a hyperechoic area containing hypoechoic spaces related to the infarcted fat. Tendon tear: Tendon injuries (e.g. biceps tendon ( Fig. 34 on page 29 ) with or without accompanying haematomas or seromas can present as diffuse or localised swellings, representing the retracted swollen tendon stump. The clinical history is typical in these cases. Vascular malformation: Vascular malformations and haemangiomas can also present as A soft tissue mass. Haemangiomas ( Fig. 35 on page 29 ) are endothelial lined neoplasms, that mainly occur during childhood and can be categorized to capillary and cavernous types. Doppler demonstrates Page 7 of 35

8 marked hypervascularity, they can be hyperechoic or hypoechoic in relation to the surrounding tissues and they are often compressible as blood can be expelled from the dilated vessels. On releasing pressure, colour flow Doppler will be seen again as the vessels refill. Phleboliths when present are seen as echogenic foci within the lesion. Vascular malformations ( Fig. 36 on page 29, Fig. 37 on page 30 ) are composed of dysplastic vessels and are divided into high flow, slow flow and capillary lesions. They are usually characterized by an abnormal network of vascular channels, interposed between a prominent feeding artery and a dilated draining vein, which occasionally can be seen. Page 8 of 35

9 Images for this section: Fig. 1: Hyperechoic lesion within the subcutaneous tissues, without any vascularity, consistent with a subcutaneous lipoma. Note the parallel to the skin axis of the lesion. Fig. 2: Although the long axis imaging is suggestive of an intrafascial lipoma, the short axis imaging proves the intramuscular location of the lesion. Page 9 of 35

10 Fig. 3: Large intramuscular lipoma of the distal biceps with mild vascularity. Page 10 of 35

11 Fig. 4: Same patient with Fig 3. T1w and STIR sequences clearly show the lipomatous nature of the lesion. Page 11 of 35

12 Fig. 5: Intrafascial lipoma without abnormal vascularity located at the antecubital fossa. At the long axis view the hyperechoic bands of the fascia surrounding the mass are more obvious. Page 12 of 35

13 Fig. 6: Patient presented with clinical evidence of anterior interosseous nerve compression syndrome.x-ray, US and MRI images revealing a deep seated lipoma, deep to the anterior compartment of the forearm most likely compressing the anterior interosseous nerve. Page 13 of 35

14 Fig. 7: Baker's cyst. Longitudinal and transverse and images show a well-defined cystic lesion originating between the semimembranosous tendon and the tendon of medial head of the gastrocnemius. Thin septations, mild wall thickening and few internal echoes are noted. Page 14 of 35

15 Fig. 8: Volar ganglion transverse and longitudinal, grey-scale and Doppler images demonstrate the relation of the ganglion cyst with the radial artery and the flexor carpi radials tendon as well as with the distal radius (RAD) and the scaphoid bone (SC). Fig. 9: Transverse and longitudinal grey- scale and Doppler images demonstrate a well defined cystic lesion without internal vascularity at the level of the mid phalanx, abutting the flexor tendon sheath. Tendon sheath ganglion. Fig. 10: Well-defined cystic lesion with acoustic enhancement and slightly echogenic content within the subcutaneous tissues. Sebaceous cyst. Page 15 of 35

16 Fig. 11: Sizable swelling overlying the olecranon. Transverse grey-scale and Doppler images of olecranon bursitis. The olecranon bursa appears thickened, with effusion and increased vascularity. Fig. 12: Grey-scale and Doppler images of a lobulated fluid collection, with increased peripheral vascularity underlying the distal biceps tendon. Bicipitoradial bursitis. Page 16 of 35

17 Fig. 13: US and MRI images show distended bicipitoradial bursa surrounding the distal biceps tendon. Fig. 14: Longitudinal and transverse grey-scale and Doppler images demonstrate marked thickening of the prepatellar bursa with a small fluid collection and slightly increased vascularity. Prepatellar bursitis. Page 17 of 35

18 Fig. 15: Grey-scale and Doppler images. A hyperechoic metallic foreign body is seen, with resulting inflammatory mass with increased vascularity. Fig. 16: Grey- scale and Doppler images of abscess and cellulitis at the posterior elbow. Note the thick septations and the internal echoes. Page 18 of 35

19 Fig. 17: Grey-scale and Doppler images of a well-defined, hypoechoic lesion in a patient with lympadenitis, consistent with enlarged inflamed lymph node. Note the central vessel at the hilum. Page 19 of 35

20 Fig. 18: Grey scale and Doppler images of an elbow joint effusion with mixed echogenicity content, proven to be pus following aspiration. Page 20 of 35

21 Fig. 19: US in a patient with known rheumatoid arthritis. Rheumatoid nodule pressumed. However US revealed a dilated joint recess with viscous effusion. By increasing the pressure with the probe the fluid is re-entering the joint. Page 21 of 35

22 Fig. 20: Same patient with Fig 19. MRI demonstrates effusion in the anterior recess of the joint. Please note the multiple rice bodies within the effusion. Fig. 21: Longitudinal and transverse images of the elbow in a patient with known gout. A soft tissue lump noted posterior to the olecranon, with mixed echotexture, hyperechoic specks and increased vascularity. Gouty tophus. Page 22 of 35

23 Fig. 22: Grey scale and Doppler image of the lateral elbow in a young adult reveals a well-defined mass with scattered calcified foci and posterior acoustic attenuation. Note is made of mild peripheral vascularity. Surgically proven Pilomatrixoma. Fig. 23: Grey-scale and Doppler images demonstrate a hypoechoic non-vascular nodule intimately related with the medial fibres of the plantar fascia. Plantar fibroma. Page 23 of 35

24 Fig. 24: Long and short axis views of a palmar fibroma between the 4th flexor tendon and the skin. Fig. 25: Morton's neuroma. Well-defined, non-compressible hypoechoic lesion at the 3rd web space. The patient demonstrated also positive Moulder's sign. Page 24 of 35

25 Fig. 26: Schwannoma of the ulnar nerve proximal to the elbow. Long axis images of a hypoechoic mass in close continuity with the nerve (neural tail), and acoustic enhancement. Fig. 27: Same patient with image 26. MRI coronal T1W, STIR and post contrast T1W images show clearly the enhancing nerve sheath tumour in continuity with the ulnar nerve. Page 25 of 35

26 Fig. 28: Schwannoma of the median nerve. Fig. 29: Long and short axis images of a liquefying haematoma of the biceps. No vascularity is seen. Page 26 of 35

27 Fig. 30: Patient presented with anteromedial calf pain and swelling. Could not recall any trauma. US and Doppler US demonstrate an organizing haematoma. Note internal echogenicity and mild peripheral hyperaemia. Page 27 of 35

28 Fig. 31: Same patient with Fig 30. T1w and STIR axial images confirm the anteromedial calf haematoma. Fig. 32: Patient presented with a lump over the left trochanter. Previous history of trauma (fell of a horse). A well circumscribed hypoechoic fluid collection without any vascularity. The appearances in addition with the patient's history and classic location are suggestive of a Morel-Lavalee lesion. Fig. 33: Short and long axis images display heterogeneous hyperechoic changes at the subcutaneous fat. Patient had a history of previous trauma. Post-traumatic fat necrosis. Page 28 of 35

29 Fig. 34: Long and short axis images of a tear of the biceps tendon in a male patient presented with a swelling at the proximal elbow. The retracted tendon along with moderate volume effusion are noted. Fig. 35: Subcutaneous hypoechoic hypervascular lesion, with a calcified phlebolith. Haemangioma. Page 29 of 35

30 Fig. 36: Lump on the index finger on a young patient. US, Doppler studies demonstrate a hypoechoic highly vascular lesion with a feeding artery and a dilated draining vein. Vascular marformation. Page 30 of 35

31 Fig. 37: Different patient with a vascular malformation at the medial thigh. Note the vascular channels on the grey-scale image and the vascular nature and feeding artery originating from deep soft tissues at the Doppler images. Page 31 of 35

32 Conclusion Ultrasound can significantly aid in the differentiation of benign soft tissue mass and also in the differential diagnosis of malignant versus benign lesions. US triage of soft tissue masses is an accurate mean of determining patient management strategies, rationalizing at the same time the use of MRI imaging. Page 32 of 35

33 Personal information Dr V Skiadas Consultant Musculoskeletal Radiologist University Hospital Southamtpon. vasileios.skiadas@uhs.nhs.uk Page 33 of 35

34 References 1) Ultrasound evaluation of soft tissue masses and fluid collections. S.E. Smith, J. Salanitri, D. Lisle. Semin Musculoskelet Radiol 2007;11: ) Sonographic evaluation of palpable superficial masses. Di Domenico P., Middleton W. Radiol Clin North Am 2014 Nov;52(6): ) Ultrasound of soft tissue masses. Bureau NJ, Cardinal E, Chhem PK. Semin Musculoskelet Radiol 1998;2(3): ) Ultrasound and Doppler US in evaluation of superficial soft tissue lesions. H. Toprak, E. Kilic, A. Serter, E. Kocakoc, S. Ozgocmen. J Clin imaging Sci 2014;4:12. 5) Ultrasound of musculoskeletal soft tissue tumors superficial to the investing fascia. E.H. Yee Hung, J.F. Griffith, A.W. Hung NG, R.K. Lok Lee, D.T. Yi Lau, T.C. Shun Leung. AJR 2014;202:W532-W540. 6) Soft-tissue Lipomas: Accuracy of Sonography in diagnosis with Pathologic Correlation. P. Inampudi, J. A. Jacobson, D. P. Fessell, R. C. Carlos, S. V. Patel, L. O. Delaney-Sathy, M. T. Van-Holsbeeck. Radiology 2004; 233: ) Soft-tissue tumors and tumorlike lesions: A systematic imaging approach. J.S. Wu, M. G. Hochman. Radiology: Volume 253:2- November ) Ultrasound of musculoskeletal soft tissue masses. A. Kinare, M. Brahmnalkar, S. D'Costa. Indian J Radiol Imaging/August 2007/V0l 17/Issue 3. 9) Ultrasonographic findings in patients with olecranon bursitis. Blankstein A., Ganel A., Givon U., Mirovski Y., Chechick A.. Ultrashall Med Dec; (6): Epub 2006 Feb ) Sonography of the bicipitoradial bursa. A short pictorial essay. F. Draghi, B. Gregoli, C. Sileo. Journal of Ultrasound (2012) 15, ) Sonography first for subcutaneous abscess and cellulitis evaluation. Srikar Adhikari, Michael Blaivas. J Ultrasound Med 2012;31: Page 34 of 35

35 12) Peripheral nerves of the extremities; imaging with US. D. Fornage. Radiology Volume 167, issue 1,April ) Ultrasound of the musculoskeletal system. S. Bianchi, C. Martinoli. Springer Book. 14) Practical Musculoskeletal Ultrasound Eugene G. McNally. Elsevier Book. Page 35 of 35