Merkel cell carcinoma in a rare but very aggressive neuroendocrine skin carcinoma mainly occurring in the head and neck of elderly patients, but cases of breast metastasis are considered unusual. We report a rare case of breast metastasis in Merkel cell carcinoma of the lower eyelid.
A 58-year-old woman reported an asymptomatic tumor on the left lower eyelid and an asymptomatic swelling on the parotid gland. Both tumors were radically dissected. Histological studies indicated Merkel cell carcinoma originating from the eyelid and metastasizing to the parotid gland and cervical lymph nodes.
Five months after surgery, the patient reported 1.8cm mass on the right breast. Histological needle biopsy diagnosis indicated a malignant tumor, and the right breast with axillary lymph nodes was resected. Cervical postoperative radiotherapy of 46 Gy was delivered and adjuvant chemotherapy added. Histological and immunohistological studies showed a metastasizing Merkel cell carcinoma lesion in the mammary gland.
Four months after the breast operation, computed tomography revealed multiple metastastic lesions in the superior mediastinum, pancreas and left adrenal. The patient died 9 months after the breast operatson.