Small Cell Carcinoma of the Kidney
A 52-year-old woman had a 2-week history of right flank pain and intermittent hematuria with iron deficiency anemia. Physical examination of the patient was unremarkable, except for an abdominal mass and CVA tenderness. Laboratory data were as follows: white blood count 8,280/µL, platelet 346,000/µL, hemoglobin 9.5 g/dL, MCV 74.3 fl, MCH 24.4 pg, MCHC 32.8 g/dL; serum blood urea nitrogen 12.7 mg/dL, serum creatinine 0.89 mg/dL. Urinalysis showed microscopic hematuria. A computed tomography (CT) scan of the abdomen revealed a relatively well defined, large heterogeneous tumor in the right kidney (). CT scans of the brain and chest, as well as a bone scan were carefully examined to look for signs of metastatic disease. There were no evident metastases at regional lymph nodes or at any distant organs. The preoperative impression was a renal cell carcinoma; the patient underwent a right radical nephrectomy. Macroscopically, a very large mass measuring 10×15 cm, from the right kidney, was identified (). Cut sections were grey-yellow in color and contained bloody and serosanguinous fluid. The tumor penetrated the capsule, but there was no infiltration into the renal pelvis, hilus of the kidney or adjacent lymph nodes. Histological examination revealed a pure small cell carcinoma with scant cytoplasm and stippled nuclear chromatin (). Immunohistochemical stains revealed that the tumor cells were strongly positive for synaptophysin, weakly positive for chromogranin, and negative for S-100, leukocyte common antigen (). We concluded that this case represented a pure small cell carcinoma of the kidney. Postoperatively, the patient received six courses of adjuvant chemotherapy consisting of etoposide and cisplatin. Upon completion of the chemotherapy, all oncological investigations, including abdominopelvic CT and chest X-ray, revealed no evidence of recurrence. Outpatient follow-up of laboratory and radiographic studies were performed at regular intervals. The patient is currently well without any evidence of recurrence at 28 months following the primary diagnosis.