Primitive neuroectodermal tumour of the kidney in a young female: a case report

We present a case of a PNET of the kidney in a 20-year-old female. This is an extremely rare presentation. Primitive Neuroectodermal Tumours (PNET) occurs preferentially in the soft-tissues of the paravertebral region and chest wall, less frequently in extremities, with a male predominance. Few cases have been reported in literature with a variable, non-specific presentation and an aggressive behaviour. In our case, a radical nephrectomy with lymphadenectomy was performed. Haematoxylin and eosin staining showed the tumour composed of cohesive sheets of small, uniform, primitive cells separated by fibrous bands. Homer-Wright pseudorosettes were present and perivascular rosetting was noted. The cytoplasm showed PAS positivity. The immunohistochemical evaluation revealed a diffuse CD99 positivity in the cytoplasm of the neoplastic cells. Neuron-Specific Enolase (NSE), synaptophysin and vimentin were positive. The clinical presentation and the macroscopic aspect, together with the histological pattern, the cytological characteristics and cellular immunophenotype addressed the diagnosis towards primary PNET of the kidney. Since the differentiation of small round cell tumours may be challenging, we reviewed the difficulties in differential diagnosis. As illustrated in this case, it is important to consider the possibility of renal PNET in young female patients presenting with a renal mass. Keywords: Renal PNET: Ewing's sarcoma: small round cell tumours
Introduction Primitive Neuroectodermal tumour (PNET) of the kidney is an extremely rare malignancy. Renal PNET is highly aggressive presenting at an advanced stage, with distant metastasis and subsequent poor prognosis. [...]