Renal small cell carcinoma (neuroendocrine carcinoma) without features of transitional cell carcinoma

Seventeen cases of renal small cell carcinoma have been reported in the literature. Approximately half of the reported cases show combined features of transitional cell carcinoma. Presented herein is a case of renal small cell carcinoma in a 37-year-old Japanese male who had been treated for 10 years with famotidine for duodenal ulcer. He suffered from sudden-onset chest pain at presentation and myxoma of the right atrium was suspected. He was treated by atriotomy and a tumor was removed from the right atrium and pulmonary artery. Histological examination, however, revealed it to be small cell carcinoma. Accordingly, a radical operation was performed for the removal of a tumor found in the right kidney. Histological examination of the tumor confirmed the presence of renal small cell carcinoma without any features of transitional cell carcinoma. It is reported that long-term administration of an histamine 2 (H2) receptor antagonist may produce carcinoid tumors in rodents and enterochromaffin-like cell hyperplasia in humans. The possible relationship between neuroendocrine carcinoma and H2 receptor antagonist therapy is discussed.