Neuron-specific enolase-positive rosettes in nephroblastoma: a possible diagnostic pitfall in aspiration cytology

Neuron-specific enolase-positive cells, some arranged in rosettes, were identified in smears obtained in fine-needle aspiration of a left retroperitoneal tumor found in a 3-yr-old boy. Nephrectomy showed a typical nephroblastoma with a prominent blastemic component revealing a positive reaction for neuron-specific enolase in blastemic and tubular components. Neuron-specific, enolase-positive, small malignant cells are not diagnostic of neuroblastoma when coming from a tumor of the retroperitoneum even if rosettes are present.