Primary Pediatric Primitive Neuroectodermal Tumor of Kidney Presenting as a Lumbar Abscess: A Rare Case Report.

Abstract

Renal sarcomas are rare, accounting for less than 1% of all renal malignancies. Ewing sarcoma/PNET of the kidney is an aggressive and extremely rare neoplasm with only 120 cases reported so far. It is seen in young adults, and only few pediatric cases have been reported so far. We report an 8-year-old boy presenting with progressive left lumbar swelling for 1 year and a prior history of antitubercular therapy. Examination revealed a tender subcutaneous abscess measuring 7×5 cm in the left lumbar region. Fine-needle aspiration cytology suggested a small round blue cell tumor. Histopathological examination, supported by immunohistochemistry, confirmed the diagnosis of renal PNET, which is highly aggressive as compared to PNET arising from other sites. It needs to be distinguished from other primary renal tumors owing to its poor prognosis and aggressive nature. Clinical and radiographic features are nonspecific leading to diagnostic challenges. Definitive diagnosis requires histopathological examination and IHC.