Neuroblastoma with divergent immunophenotype - an FNAB based case report with review of literature

Abstract

A case of neuroblastoma with divergent vimentin and cytokeratin positivity in an 11 year old boy is presented. The initial radiological impression was of a left renal mass consistent with Wilms' tumor. FNA revealed a tumor with an essentially discrete population of small round cells, and a few rosette-like structures. However, the presence of rare epithelial looking cells and stromal fragments coupled with vimentin and cytokeratin positivity prompted a diagnosis of a malignant round cell tumor consistent with Wilm's tumor. The appearance of skull metastasis a few weeks later prompted a review of the diagnosis. A repeat CECT scan clearly indicated a left adrenal origin of the mass. Material from a repeat FNA was submitted for electron microscopy. The detection of neurites confirmed a neuroblastoma. The earlier vimentin and cytokeratin positivity, confirmed by flowcytometry, was taken as evidence of a divergent immunophenotype. The subject of divergent differentiation in small round-cell tumors with neural features is reviewed.