[A case of small cell carcinoma of kidney; solitary splenic metastasis].

A 67-year-old male visited a hospital with a complaint of right flank pain. A computed tomography and magnetic resonance imaging demonstrated a right renal tumor, lymphadenopathy, and a splenic tumor. Right radical nephrectomy, lymph node dissection, and splenectomy were performed. Histological examination of the renal tumor and lymph node revealed small cell anaplastic carcinoma. A dilated renal pelvis was focally covered with transitional cell carcinoma grade 2. Splenic tumor revealed a mixture of small cell and giant cell anaplastic carcinoma. Immunostaining for NSE and cytokeratin were positive. He received 2 courses of adjuvant chemotherapy with cisplatin and etoposide. The patient is alive for 10 months after surgery and free of carcinoma. This is the 10th case of renal small cell carcinoma reported in Japan. The clinical features and managements of these rare tumors are discussed.