Breast Cancer Mimics

CHAPTER 7 Breast Cancer Mimics



A variety of processes, both benign and malignant, may mimic primary breast carcinoma.14 Many of these can be distinguished from breast cancer on the basis of imaging findings alone. However, some may ultimately require histopathologic confirmation. The most common benign causes of masses in women are fibroadenomas and breast cysts.5 High-quality imaging, including diagnostic mammography and high-resolution ultrasound and strict adherence to interpretive criteria can, for the most part, distinguish fibroadenomas and cysts from breast cancer. However, because there is sufficient overlap in the appearance of benign and malignant lesions, a new or enlarging solid mass that is not classically benign (e.g., hamartoma or lipoma) requires biopsy. In addition to lesions related to the duct-lobular system, mimics of primary breast cancer may also be caused by a wide spectrum of pathologic disorders arising in mesenchymal structures of the mammary gland. These include tumors arising in the stroma of the breast that are breast specific, such as pseudoangiomatous stromal hyperplasia (PASH) and phyllodes tumors, as well as tumors arising from non-breast-specific stromal structures, including fibrous tissue, vascular structures, lymphoid tissue, nerves, and skin. These non-breast-specific tumors include focal fibrosis, fibromatosis, malignant fibrohistiocytomas, vascular malformations, angiosarcomas, neurofibromas, lymphomas, and liposarcomas. In addition, cancer mimics may also be caused by inflammatory processes (foreign body reaction, mastitis, and abscess), trauma (hematoma, fat necrosis), lactational changes, and metastasis from extramammary malignancies.



EPITHELIAL BREAST LESIONS







LESIONS OF THE BREAST STROMA (BREAST SPECIFIC)




Phyllodes Tumor


Phyllodes tumor, also called cystosarcoma phyllodes, are unusual fibroepithelial tumors composed of epithelium and a spindle cell stroma and can exhibit a wide range of clinical behavior. Radiographically they present as a rapidly growing, hypoechoic, circumscribed mass.16 They are classified as benign, borderline, or malignant based on histopathologic features. However, histologic classification does not always predict outcome. The prognosis of phyllodes tumors is favorable, with local recurrence in about 15% of patients overall and distant recurrence in about 5% to 10%.



LESIONS OF THE BREAST STROMA (NONBREAST–SPECIFIC)






Vascular Tumors


Vascular tumors of the breast are uncommon and include hemangiomas and angiosarcomas.20 Hemangiomas are extremely rare, are usually smaller than 2 cm, and can be differentiated from dermal hemangiomas by their distinct separation from the epidermis. Mammographically, breast hemangiomas are small, well-defined, lobulated masses. On ultrasound, their appearance may be variable, being either circumscribed hypoechoic masses, mixed echogenicity masses, or ill-defined hyperechoic masses (Figure 4). Angiosarcomas of the breast are more common than hemangiomas and are usually larger in size. Radiographically, they present as an ill-defined calcified or noncalcified hypoechoic mass. They may occur in the chest wall as a rare complication following radiation therapy for primary breast cancer.






MISCELLANEOUS BREAST LESIONS




Dec 24, 2015 | Posted by in BREAST IMAGING | Comments Off on Breast Cancer Mimics

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