Recurrent neuroendocrine (Merkel cell) carcinoma of the skin presenting as marrow failure in a man with systemic lupus erythematosus.

Neuroendocrine carcinoma of the skin, Merkel cell carcinoma, is an aggressive malignancy with a high incidence of local recurrence and metastasis. We describe a case of neuroendocrine carcinoma of the skin with unusual metastatic spread to the bone marrow in a 55-year-old man with systemic lupus erythematosus. Following resection of a left temporal subcutaneous nodule and complete left parotidectomy and radical lymph node dissection, the patient presented with pancytopenia. Although focal bony metastatic disease was not identified, his bone marrow was diffusely replaced by metastatic carcinoma. High-dose chemotherapy allowed a brief remission; however, the patient subsequently died with central nervous system metastases.