Merkel cell carcinoma of the breast: report of a case and review of the literature.

CASE REPORT A 52-year-old lady presented to A&E in November 2001 with a history of an injury to the upper outer quadrant of the left breast several weeks previously. On examination she had a markedly abnormal left breast. A fungating tumour occupied the upper outer quadrant of the breast with the rest of the breast swollen, oedematous and very firm. Ultrasound scan showed no focal mass but the entire breast was abnormal with areas of low density and interstitial oedema. An Ultrasound guided fine needle aspirate revealed malignant cells. The main differential diagnosis lay between a poorly differentiated carcinoma and a high grade lymphoma therefore a core biopsy was obtained. The core biopsy suggested a small cell carcinoma arising primarily within the breast. A staging CT scan of chest and bone scan revealed liver and bony metastases and chemotherapy was commenced.