Breast imaging of benign fat containing lesions

Transcription

1 Breast imaging of benign fat containing lesions Poster No.: C-1870 Congress: ECR 2017 Type: Educational Exhibit Authors: R. Aouini, I. Megdiche, D. Ben Hammadi, N. BEN MAMI, I. Attia, R. Neila, A. Zidi; Salah Azaiz Institute/TN Keywords: Pathology, Diagnostic procedure, Ultrasound, Mammography, Breast DOI: /ecr2017/C-1870 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 29

2 Learning objectives To highlight and illustrate radiologic features of common fat-containing breast lesions on mammography and ultrasonography. Background Fat-containing breast lesions are a heterogeneous group of predominantly benign tumors: hamartoma, lipoma, fat necrosis, oil cyst, lymphe nodes and galactocele are the most common lesions. Usually, their radiologic appearance is characteristic and definitive diagnosis is possible without biopsy or surgery. These lesions should be recognized by radiologists to ovoid unnecessary workup and ensure appropriate management. Findings and procedure details This study is a pictorial essay of the imaging features of fat containing breast lesions in patients who presented with breast symptoms or referred to us for screening. All patients underwent a clinical examination before radiologic investigation. A conventional X-ray mammography was performed with at least craniocaudal and mediolateral oblique views. Breast ultrasonography was performed using a Logic E9 GE machine. We illustrated the radiological features and the common lésions of fat containing breast tumors such as oil cyst (n=3); hamartoma (unilateral and multiple) (n=7); lipoma (n=4), fat necrosis (n=5), Intra-mammary lymph node (n=4) and galactocoele (n=2). In 6 cases, the tumor was surgically removed with anatomopathological confirmation. 1/Hamartoma (= Fibroadenolipoma): Fig. 1 on page 11, Fig. 2 on page 13, Fig. 3 on page 13, Fig. 4 on page 14, Fig. 5 on page 15 and Fig. 6 on page 16 Hamartoma is an uncommon breast tumor that accounts for 4.8% of all benign breast masses with an incidence of 0.1% to 0.7% [2,3]. They often present as mobile and soft breast lump or breast enlargement without a palpable lesion, in a middle-aged woman. Page 2 of 29

3 It results from a proliferation of variable amounts of fibrous, glandular, and fatty tissue surrounded by a thin capsule of connective tissue. The variable proportion of fat and fibrous connective tissues results in variation of radiologic appearance. In mammography, hamartoma typically appears as a round to oval mass with a heterogeneous internal density made of both fat (radiolucent component) and soft-tissue densities (radiodense components). The lesion is well circumscribed, surrounded by a thin pseudocapsule and a peripheral radiolucent zone. The radiopaque pseudocapsule is formed from the displaced adjacent normal breast tissue. Lobulated densities are dispersed within the encapsulated fatty lesion described as "breast within a breast", "slice of salami" or "slice of sausage" appearance. There may be associated to benign amorphous or smooth round microcalcifications Page 3 of 29

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5 Fig. 1: A 47-year-old woman with a left breast lump; mammogram shows an ovoid mass surrounded by a thin pseudocapsule, made of mixed radiolucent fatty and dense fibroglandular tissue pattern. Lobulated densities are dispersed within the fatty lesion making a "breast within a breast" appearance typical of hamartoma. References: - Salah Azaiz Institute/TN On sonography, hamartoma has a mixed internal echotexture with both hyperechoic and hypoechoic components. the lesion is usually well-circumscribed, soft and easy to compress. Sometimes, it is difficult to delineate the margins since it resembles the normal breast tissue. In mammography as well as sonography, they displace the adjacent normal breast tissue. Fig. 4: Ultrasound of the previous lesion shows the internal inhomogenicity of the hamartoma with fibrous strands similar to the adjacent normal breast tissue and hyperechoic component corresponding to fatty tissue. An echogenic rim is seen corresponding to the pseudocapsule. References: - Salah Azaiz Institute/TN Sometimes, hamartoma may appear to be homogeneously dense when it is rich in fibrous tissue mimicking a fibroadenoma, or homogeneously radiolucent mimicking a lipoma. Multiple breast hamartomas may be associated with some genetic abnormalities such as Cowden syndrome (also known as Multiple Hamartoma syndrome) which is characterised by multiple hamartomas throughout the body (breast, mucocutaneous, gastrointestinal...) and an increased risk of several cancers. Page 5 of 29

6 2/Lipoma: Fig. 7 on page 17, Fig. 8 on page 18, Fig. 9 on page 19 and Fig. 10 on page 20 Lipomas are benign mesenchymal tumors composed of mature fatty tissue, well circumscribed, and covered by a thin capsule. Lipomas are mostly asymptomatic incidentally diagnosed on routine screening. In some cases, patients may present with a palpable breast lump which is soft and movable. The mammogram shows a uniform radiolucent mass with well-defined thin smooth capsule and no intrinsic density. Fig. 7: A retroareolar lipoma diagnosed in a A 43-year-old woman with a palpable soft left breast lesion. the mass is homogenously radiolucent with a very thin capsule. Page 6 of 29

7 References: - Salah Azaiz Institute/TN Ultrasound demonstrates a homogeneous iso-echoic or slightly hyperechoic to surrounding fat lesion which is most frequently seen in the subcutaneous plane. A lipoma may appear hypo-echoic with multiple thin echogenic septations parallel to the skin surface Fig. 8 on page 18 and Fig. 10 on page 20. Fig. 10: A hypo-echoic lipoma (yellow arrows) with thin echogenic septations (red arrows) parallel to the skin surface, posterior acoustic enhancement. References: - Salah Azaiz Institute/TN Lipomas can be difficult to diagnose in large or postmenopausal breasts. Page 7 of 29

8 3/ Oil cysts and fat necrosis:fig. 11 on page 21, Fig. 12 on page 22 and Fig. 13 on page 23 Fat necrosis is a nonsuppurative inflammatory process. Oil cyst occurs when an area of focal fat necrosis becomes walled off by fibrous tissue. Later, cavitation and calcification of the thin fibrous wall may occur. It's commonly seen after breast surgery, trauma, infection, radiotherapy or in duct ectasia. Rarely, oil cysts arise independently, without a prior history particularly of trauma or surgery. The incidence of fat necrosis is 0.8% of breast tumors and 1% of breast reduction surgery. Patients usually present with a painless or painful poorly indurated mass near the skin or areola associated in some cases to inflammation or thickening of the overlying skin. The mammographic features of fat necrosis change with time and may have sometimes an alarming appearance, thus, comparison with previous imaging is essential. Page 8 of 29

9 Fig. 11: Evolution of fat necrosis after surgical removal of a malignant breast tumor (red arrow): One year after surgery, fat necrosis (yellow arrow) appears with a slightly radiolucent center. After 4 years, the lesion decreased in size, the center is increasingly homogenous with fat-density and a thin capsule, appearance of dystrophic calcifications. References: - Salah Azaiz Institute/TN Initially, it can be seen as an ill-defined and irregular, spiculated mass-like area, the low density centres in mammography corresponding to fatty component and the correlation with the position of surgical scarring on the breast are helpful to make the diagnosis Fig. 11 on page 21. With time, it becomes more defined and well-circumscribed giving rise to an oil cyst. Oil cyst appears as a round or oval radiolucent lesion, the center becomes increasingly homogenous with fat-density and a thin capsule. It may be associated with uniform continuous egg-shell calcification. Page 9 of 29

10 Fig. 13: bilateral oils cysts associated to duct ectasia, no rpior history of breast surgey ou trauma. References: - Salah Azaiz Institute/TN Ultrasound of fat necrosis should always be interpreted in the context of mammographic findings. It may demonstrate increased echogenicity of subcutaneous tissues, anechoic cyst with posterior acoustic enhancement, hypoechoic mass with posterior acoustic shadowing, cyst with internal echoes or cystic mural nodule. 4/ Intramammary Lymph nodes:fig. 14 on page 24, Fig. 15 on page 26 and Fig. 16 on page 26 Normal lymph nodes within the breast tissue are common, seen in ~5% of mammographic studies. They can be solitary or multiple with a predilection for the upper outer quadrant. Normal lymph nodes are usually seen as well defined, smoothly circumscribed, oval or reniform mass with a central or peripheral lucency that represents fat within the hilum. The majority (~78%) of lesions have a lower density at the centre than at the periphery on mammography and in some cases a hilar notch is seen. they are less than 1 cm in diameter and generally stay constant in size on follow up mammograms. In ultrasound, they are detected as a solid reniform lesion which is hypoechoic with a hyperechoic central area and a flow entering the hilum on colour. The outer margins are typically well defined. 5/ Galactocele: Fig. 17 on page 27 A galactocele is a milk-filled cyst that occurs as a result of ductal obstruction, common in young pregnant or breast-feeding women. It is most likely that the breast lesion will be diagnosed by ultrasound since mammograms are generally not performed on pregnant women. Milk secretions tend to be fatty, that's why the radiologic appearance of a galactocele will depend on the amount of fat and proteins in the fluid. In general, it appears as an oval circumscribed mass whose radiolucency indicates a high fat content. On ultrasound, it appears as a round hypoechoic to hyperechoic nodule with well-defined margins and a thin echogenic wall. Page 10 of 29

11 Fig. 17: ultrasound of a galactocele in a breast-feeding woman. References: - Salah Azaiz Institute/TN Images for this section: Page 11 of 29

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13 Fig. 1: A 47-year-old woman with a left breast lump; mammogram shows an ovoid mass surrounded by a thin pseudocapsule, made of mixed radiolucent fatty and dense fibroglandular tissue pattern. Lobulated densities are dispersed within the fatty lesion making a "breast within a breast" appearance typical of hamartoma. Fig. 2: Mammography of a right palpable breast mass of 12 cm in a 38-year-old woman showing a predominantly dense breast hamartoma. The lesion was surgically removed with histological final diagnosis of fibroadenolipoma. Page 13 of 29

14 Fig. 3: An upper outer fibroadenolipoma containing benign calcifications (yellow arrow) and compressing the adjacent normal breast tissue. Page 14 of 29

15 Fig. 4: Ultrasound of the previous lesion shows the internal inhomogenicity of the hamartoma with fibrous strands similar to the adjacent normal breast tissue and hyperechoic component corresponding to fatty tissue. An echogenic rim is seen corresponding to the pseudocapsule. Page 15 of 29

16 Fig. 5: mammography of bilateral and multiple hamartomas Page 16 of 29

17 Fig. 6: bilateral and multiple hamartomas Page 17 of 29

18 Fig. 7: A retroareolar lipoma diagnosed in a A 43-year-old woman with a palpable soft left breast lesion. the mass is homogenously radiolucent with a very thin capsule. Page 18 of 29

19 Fig. 8: Upper outer superficial brest lipoma. US: a slightly hypo-echoic well defined lesion runned by thin echogenic septations parallel to the skin surface, with a posterior acoustic enhancement. Page 19 of 29

20 Fig. 9: US: typical yperechoic breast lipoma Page 20 of 29

21 Fig. 10: A hypo-echoic lipoma (yellow arrows) with thin echogenic septations (red arrows) parallel to the skin surface, posterior acoustic enhancement. Page 21 of 29

22 Fig. 11: Evolution of fat necrosis after surgical removal of a malignant breast tumor (red arrow): One year after surgery, fat necrosis (yellow arrow) appears with a slightly radiolucent center. After 4 years, the lesion decreased in size, the center is increasingly homogenous with fat-density and a thin capsule, appearance of dystrophic calcifications. Page 22 of 29

23 Fig. 12: pre pectoral Oil cyst after surgical removal of a malignant breast tumor Page 23 of 29

24 Fig. 13: bilateral oils cysts associated to duct ectasia, no rpior history of breast surgey ou trauma. Page 24 of 29

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26 Fig. 14: Intramammary Lymph node seen as a reniform lesion with a central lucency that represents fat within the hilum. Fig. 15: Intramammary Lymph node nearby a vessel Page 26 of 29

27 Fig. 16: Norrmal lymph node in ultrasonography: Note the hyperechoic central area corresponding to the hilium. Page 27 of 29

28 Fig. 17: ultrasound of a galactocele in a breast-feeding woman. Page 28 of 29

29 Conclusion Correlating mammographic with breast ultrasonography findings often helps in identifying most common fat-containing breast tumors that should be considered as «leave me alone» lesions. Personal information References [1]M.H. Pui, I.J. Movson. Fatty tissue breast lesions. Journal of Clinical Imaging 27 (2003) [2]Aggelatou R, Mouselimi M, Panou A. The role of mammography in the diagnostic approach of breast hamartomas. Eur J Gynaecol Oncol 1998;19: [3] Arrigoni MG, Dockerty MB, Judd ES. The identification and treatment of mammary hamartoma. Surg Gynaecol Obstet 1971;133: [4] Meyer JE, Ferraro FA, Frenna TH et-al. Mammographic appearance of normal intramammary lymph nodes in an atypical location. AJR Am J Roentgenol. 1993;161 (4): Page 29 of 29