A Rare Renal Pediatric Tumor: Metanephric Stromal Tumor

A left abdominal mass revealed a metanephric stromal tumor in an 8-month-old infant. But before that, the ultrasound and CT scan of the mass suggested a nephroblastoma. This motivated neoadjuvant chemotherapy before total left nephrectomy. The sections of the Surgical specimen showed a whitish tumor of intramedullary location. On microscopic examination, the tumor corresponds to undifferentiated tumor proliferation. This imprecise diagnosis motivated an additional immunohistochemical study, which showed a CD34 positivity. The comparison of the histological aspects with the immunohistochemical aspects made it possible to confirm the diagnosis of a metanephric stromal tumor. The radiological check-up, carried out one year later, revealed no signs of recurrence. In this case, we would like to recall that, in addition to the impossibility of distinguishing radiologically, metanephric stromal tumor from clear cell renal sarcoma, imaging, not very helpful to the diagnostic approach of the first entity, could expose the patient to unnecessary neoadjuvant chemotherapy.