Primitive neuroectodermal tumor of the kidney with inferior vena cava and atrial tumor thrombus.

Abstract

Primitive neuroectodermal tumor of the kidney is a rare malignancy. We report a case of renal primitive neuroectodermal tumor with a level IV inferior vena caval thrombus that was managed successfully with deep hypothermic circulatory arrest. CASE REPORT A 55-year-old woman presented with vague left lower quadrant discomfort. Physical examination and laboratory tests were unremarkable. Computerized tomography (CT) of the abdomen and pelvis revealed a 5.7 4.7 cm. heterogeneously enhancing right renal mass with thrombus noted in the right renal vein extending superiorly to the level of the right atrium (fig. 1). Transesophageal echocardiography confirmed a large right atrial thrombus. Chest CT showed a 2.5 cm. left lower lobe mass, which on biopsy demonstrated benign fibro-connective tissue. The patient underwent right radical nephrectomy and level IV inferior vena caval thrombectomy with cardiopulmonary bypass and deep hypothermic circulatory arrest. Gross examination revealed a firm 5.2 cm. mass in the right kidney. Microscopically there were sheets and lobules of cells with round to oval nuclei and coarse chromatin, as well as Homer Wright rosette formation. Immunohistochemical analysis showed strongly positive staining for CD99 (fig. 2) and negative staining for other neuroendocrine markers such as synaptophysin and chromogranin. No molecular analysis was performed on the specimen. Presently the patient remains disease-free at limited followup 5 months postoperatively. Repeat CT of the chest, abdomen and pelvis before starting chemotherapy was negative for metastatic disease, and the previously noted chest lesion was found to be unchanged in size. The patient has completed 2 cycles of ifosfamide, cyclophosphamide and doxorubicin, and has tolerated the chemotherapy well without significant side effects. DISCUSSION