Primitive Neurectodermal Tumour of Kidney – An Uncommon Tumour At a Rare Site

Abstract

A case of Primitive Neuroectodermal Tumour (PNET) of the kidney in a 31-year-old gentleman is presented. Few cases are reported in the literature with a variable, nonspecific presentation and an aggressive behaviour. In our case, a radical nephrectomy, lymphadenectomy and IVC repair was performed. The surgical specimens were formalin-fixed and paraffin embedded. The sections were stained with routine H&E. Immunohistochemistry was performed. The immunohistochemical evaluation revealed CD99 positive, membrane positivity, NSE positivity, Synaptophysin-focal positivity and EMA-negativity. The clinical presentation and the macroscopic aspect, together with the histological pattern, the cytological characteristic and the cellular immunophenotype addressed the diagnosis towards primary PNET of kidney. Since sometimes it is difficult to discriminate between PNET and Ewing’s tumour, we reviewed the difficulties in differential diagnosis. These tumours have a common precursor but the stage of differentiation in which it is blocked is probably different. This could also explain their different biological behaviour and prognosis.