Cytogenetic study of glioneuronal tumor with neuropil-like islands: a case report.

Glioneuronal tumor with neuropil-like islands (GTNI) is a recently recognized glioneuronal neoplasm but it was classified as an astrocytic tumor by the World Health Organization (WHO) in 2007. We performed a cytogenetic study in a case of GTNI arising in a 55-year-old man and analyzed its genetic alteration. It presented as a heterogeneously enhancing, multi-lobulating solid mass on MRI. Histopathologically, the tumor showed the biphasic feature of the predominating micronodular neuropil-like islands and the diffusely infiltrating glial component. In addition, the prominent blood vessels with perivascular hyalinization were observed. On cytogenetic study, loss of 4q, 5q, 11p and gain of 6p, 7, 8, 11q, 12p, 15q were found. The remaining tumor after subtotal resection progressed 7 months later, despite combined chemo- and radiotherapy. From the results, it seems that GTNI does not share pathologic or genetic features with conventional astrocytoma, suggesting a unique entity with aggressive behavior.