Small Blue Round Cell Tumor Of The Kidney In Childhood - A Diagnostic Dilemma

摘要

Neuroblastoma, monophasic Wilms’ tumor (blastemal dominant) and rhabdoid tumor are the common renal round cell tumors of early childhood. The treatment modalities of these malignancies are very different. Neuroblastoma arising from the kidney may easily be misdiagnosed as a case of Wilms’ tumor. We report a case of small round cell tumor of the right kidney and based on clinical examination, imaging examination and H&E stain we consider it as monophasic Wilms’ tumor/rhabdoid tumor. Immunohistochemistry (IHC) confirmed the diagnosis of neuroblastoma resolving the diagnostic dilemma of round cell tumor of the kidney. Introduction Pediatric renal tumors often present in an advanced stage at first clinical examination. The primary differential diagnosis of a large palpable mass related to kidney in a young child includes Wilms' tumor, rhabdoid tumor and neuroblastoma. The location of the mass may proveuseful in preoperatively identifying the origin of these lesions. A mass localized to kidney most common is Wilms’ tumor. Intrarenal neuroblastoma is very rare and originates from either adrenal rests found within the renal tissue or from intra renal sympathetic ganglia. Here we report a case of intra renal neuroblastoma (stage 1). Case Presentation An 18 months old female child presented to the paediatric surgery outpatient clinic with chief complaint of low grade fever and mass in the abdomen. No haematuria. Imaging examination showed a heterogeneous mass arising from the upper pole of the kidney. Perinephric tissue was free. Right nephrectomy was done and perirenal fat was excised. Grossly the nephrectomy produced a specimen measuring 12.5x8.5x7cm with a tumor on the upper pole, which was grey brown and bosselated (Fig-1A). Tumor was msg 8x7x7cm, solid, soft, relatively circumscribed, grey white with reddish brown in color and with haemorrhagic, necrotic areas and gritty cut surface (Fig-1B). Histologically the tumor shows diffuse growth pattern of monophasic small round cells with hyperchromatic nuclei, inconspicuous nucleoli and scant cytoplasm (Fig-2A). There are areas of attempted rosette formation around central neuropil as well as blood vessels (Fig-2 B&C). Some areas were showing spindle nuclei. The tumor was vascular with extensive areas of necrosis and haemorrhage (Fig-2.A). Immunohistochemical studies with immunomarkers NSE, Chromogranin A, synaptophysin, GFAP, Vimentin, EMA, Cytokeratin, S-100 & Desmin were done for further categorization of the tumor. Immunohistochemistry of the tumor were strongly positive for NSE, Chromogranin A & Synaptophysin and focally positive for GFAP (Fig-3A,B &C). The tumor cells were negative for Vimentin, EMA, Cytokeratin and Desmin & S-100 protien (Fig-4 A,B,C,D&E). All these features suggest a diagnosis of intra renal neuroblastoma of the right kidney and ruled out a Wilms’ tumor and rhabdoid tumor.