Roentgen appearance of fat necrosis in the breast.

Abstract

With increasing acceptance of mammography as a useful adjunct in the diagnosis of breast disease, more mammograms are being obtained throughout the country, and as experience is gained in this relatively new discipline, the pitfalls of mammographic diagnosis are increasingly recognized. The roentgen appearance of some benign disease processes may simulate and be easily confused with that of carcinoma. In Egan's original series (2) of 2,000 consecutive mammograms, for example, 11 of 30 breast abscesses were misinterpreted as malignant lesions. Other sources of false diagnoses in this series included sclerosing adenosis, fibrocystic disease, fibroadenoma, and fat necrosis. The present communication deals with the last entity, of which 3 cases have come to our attention. In each instance a false positive diagnosis of malignant tumor was made from the mammograms. Case Reports Case I: This 66-year-old woman had noted a small lump in the upper outer quadrant of the left breast three weeks before admission. Two days later the skin over this lump was discolored. Physical examination revealed a 3 × 4-cm, irregular, stony-hard mass in the outer portion of the left breast. A small area of inflammation was present over the lesion, associated with flattening and dimpling of the skin. The mammographic appearance was interpreted as that of a 1-cm malignant lesion in the outer portion of the left breast (Fig. 1). Excisional biopsy yielded a pathologic diagnosis of fat necrosis. Case II: A 70-year-old woman complained of a mass in the left breast. Six months previously she had incurred an extensive bruise of the left breast in an automobile accident. A large area of ecchymosis with a residual mass was noted beneath the site of injury. Although the mass had apparently regressed slightly with time, the patient was referred to this medical center because of a possible malignant tumor. On examination the breasts were large and pendulous. A 5 × 8 cm, hard, irregular mass above and lateral to the left nipple appeared to be fixed to both the skin and the chest wall. Overlying the mass was a crescent-shaped area of skin retraction. Mammograms showed a 3 × 4-cm large, irregular, spiculated mass with overlying thickening and retraction of the skin (Fig. 2). The clinical and mammographic diagnoses of malignant tumor called for excisional biopsy. The pathologic diagnosis was fat necrosis with scarring and with remote and recent organizing hemorrhage. Case III: An extremely obese 67-year-old woman complained of a mass in the right breast. One month earlier she had bruised the outer aspect of the right breast in a fall. Twelve hours later, extensive ecchymosis over its right lateral aspect was associated with an underlying mass. At the time of admission the breasts were large and pendulous.