Indian Journal of Cancer Medknow Publications on behalf of Indian Cancer Society ISSN: 0019-509X EISSN: 1998-4774 Vol. 48, Num. 2, 2011, pp. 274-276

Indian Journal of Cancer, Vol. 48, No. 2, April-June, 2011, pp. 274-276

Letter to Editor

Primitive neuroectodermal tumor of kidney with tumor thrombus extending up to right atrium

AV Ashturkar¹, GS Pathak¹, SD Deshmukh¹, RS Neve²

¹ Department of Pathology, Shrimati Kashibai Navale Medical College and General Hospital, Narhe, Pune, India
² Department of Surgery, Shrimati Kashibai Navale Medical College and General Hospital, Narhe, Pune, India

Correspondence Address: G S Pathak Department of Pathology, Shrimati Kashibai Navale Medical College and General Hospital, Narhe, Pune India drgayatridp@yahoo. in

Code Number: cn11074

DOI: 10.4103/0019-509X.82906

Sir,

We report a rare case of renal primitive neuroectodermal tumor (PNET) with tumor thrombus extending from right renal vein to inferior vena cava and right atrium in a 44-year-old female. She presented with complaint of palpable, soft, and non-tender mass in the right lumbar region for the past 3 months. Computed tomography (CT) of the abdomen showed a large, lobulated heterogeneously enhancing soft tissue mass, measuring 17.4 × 11.5 × 9.3 cm arising from mid and lower pole of right kidney. The tumor thrombus was extending into the right renal vein, inferior vena cava (IVC) and occupying a significant proportion of the right atrial volume [Figure - 1]. The patient underwent right radical nephrectomy with optimal resection of tumor thrombus within the IVC. Postoperative USG was carried out to exclude presence of tumor embolus. The patient was referred to a specialty centre for further management, which she refused and subsequently died 2 months later.

Gross examination revealed an encapsulated, grayish white, lobulated mass, replacing almost all the kidney. On cut surface, the tumor showed extensive areas of necrosis and hemorrhage, with extension in the right renal vein. Microscopic examination showed a tumor composed of cohesive sheets of monomorphic, small, round cells separated by fibrous bands. The malignant cells had scanty cytoplasm, inconspicuous nucleoli, and brisk mitotic activity. True as well as pseudo-rosetting of tumor cells were noted [Figure - 2]. Immunohistochemically, the tumor cells were positive for neuron-specific enolase, chromogranin-A and CD 99 [Figure - 3], and negative for cytokeratin (CK), and leukocyte common antigen (LCA), establishing the diagnosis of primitive neuroectodermal tumor (PNET).

Differential diagnoses of primary small round cell tumors of kidney include include blastemal predominant Wilms′ tumor, PNET, rhabdomyosarcoma, neuroblastoma, lymphoma, and desmoplastic round cell tumor. Out of all these, renal PNET is a rare entity and most of the reported cases have occurred in young adults with mean age of 28−34. ^[1] In our case, the diagnosis was confirmed by positive immunohistochemical marker specially for CD99, which is cell-surface glycoprotein highly expressed by Ewing′s sarcoma and PNET. ^[2]

The cases of PNET of kidney with venous thrombus are extremely rare. ^[3] A PNET with a level IV thrombus in a 55-year-old woman has been reported which was managed successfully with deep hypothermic circulatory arrest. ^[4] In another report involving a 17-year-old girl, radical nephrectomy was performed, but the caval thrombus was left behind. ^[5] Our patient underwent right radical nephrectomy with optimal resection of tumor thrombus within the IVC and was further referred to a specialty hospital, but the patient refused further treatment. Similar observations have been documented in literature. ^[6] Our experience highlights the unusual clinical presentation in this case and importance of immunohistochemical study in the differential diagnosis of renal round cell tumors.

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