NEUROBLASTOMA AS A PROMINENT COMPONENT OF A MIXED GERM-CELL TUMOR OF TESTIS

Background. Primitive neuroectodermal tissue in teratomas of testis ha s been reported in the literature. A mixed germ cell tumor of testis w ith a prominent neuroblastoma component dictating the clinical behavio r was found to be unique. Methods. Tissue sections were stained with h ematoxylin and eosin, and immunohistochemical, ultrastructural, cytoge netic, and flow cytometric analyses were performed on the primitive ne uroectodermal component of the testicular mass. Follow-up results at 2 .5 years are included. Results. The microscopic findings on hematoxyli n and eosin slides showed cells composing the majority of the neoplasm to have features of neuroblastoma. The immunohistochemical stains sho wed positivity for neuron-specific enolase in the cells comprising the neuroblastoma, and transmission electron microscopic study corroborat ed these findings by demonstrating microtubules and rare membrane-limi ted, dense-core granules in the cytoplasm. Flow cytometry showed a hyp ertetraploid population with a large aneuploid DNA content. Cytogeneti cs revealed a hypertriploid modal number of 74 chromosomes. The clinic al features were dictated by the neuroblastoma component in a fashion similar to that of adult neuroblastomas and responded to the chemother apeutic regimen designed for treating neuroblastoma. Conclusions. The neuroblastoma component proved to be more aggressive than the other el ements of this neoplasm. This finding suggests that mixed germ cell tu mors showing a large neuroblastoma component should be treated promptl y and aggressively with chemotherapy.