Renal medullary carcinoma metastatic to the scalp

A 40-year-old woman presented to the Brooke Army Medical Center Emergency Department complaining of 2 episodes of gross hematuria. Computed tomography and intravenous pyelogram revealed a right renal mass. A radical nephrectomy was performed with complete excision of the mass with negative margins on histological examination. The patient was diagnosed with renal medullary carcinoma, Fuhrman grade 4, based upon histological examination. A positron emission tomography scan revealed no other evidence of the disease. The pathologic stage was stage I renal medullary carcinoma. Four months after her nephrectomy, the patient developed a papule on her right frontal scalp. Initially thought to be a cyst, the papule increased in size over the course of 2 months and eventually ulcerated. At that time, she presented to the Wilford Hall Medical Center Dermatology Clinic with a 2.5-cm ulcerated tumor with pink rolled borders. A punch biopsy of the tumor revealed an infiltrating carcinoma with scattered glandular lumina and desmoplastic and mucinous stroma. The carcinoma was completely intradermal. Expert consultation confirmed the diagnosis of metastatic renal medullary carcinoma. Clear cell (conventional) and papillary renal cell carcinomas are known to metastasize to the skin, including the scalp. Renal medullary carcinoma commonly metastasizes to the regional lymph nodes, lung, liver, or adrenals. To our knowledge, this is the first report of a cutaneous metastasis of renal medullary carcinoma.