We read with interest the extraordinary case report by Johnson et al describing for the first time a cutaneous metastasis (scalp) of medullary carcinoma of the kidney. We have recently seen a 23-year-old African American male who was found to have 1.5-cm cyst of the left upper forehead, thought to be an epidermal inclusion cyst. Punch biopsy revealed an undifferentiated malignant tumor with abundant eosinophilic cytoplasm and small nucleoli (Fig. 1), which was confined to the dermis and surrounded by mucinous stroma with areas of necrosis. Immunohistochemistry showed positivity for pankeratin, CK20 (focal) and CK7 (trace), and negativity for lymphoid markers, S-100 and cytokeratin 5/6.
展开▼
