Neuroblastoma as a prominent component of a mixed germ cell tumor of testis.

Background: Primitive neuroectodermal tissue in teratomas of testis has been reported in the literature. A mixed germ cell tumor of testis with a prominent neuroblastoma component dictating the clinical behavior was found to be unique.

Methods: Tissue sections were stained with hematoxylin and eosin, and immunohistochemical, ultrastructural, cytogenetic, and flow cytometric analyses were performed on the primitive neuroectodermal component of the testicular mass. Follow-up results at 2.5 years are included.

Results: The microscopic findings on hematoxylin and eosin slides showed cells composing the majority of the neoplasm to have features of neuroblastoma. The immunohistochemical stains showed positivity for neuron-specific enolase in the cells comprising the neuroblastoma, and transmission electron microscopic study corroborated these findings by demonstrating microtubules and rare membrane-limited, dense-core granules in the cytoplasm. Flow cytometry showed a hypertetraploid population with a large aneuploid DNA content. Cytogenetics revealed a hypertriploid modal number of 74 chromosomes. The clinical features were dictated by the neuroblastoma component in a fashion similar to that of adult neuroblastomas and responded to the chemotherapeutic regimen designed for treating neuroblastoma.

Conclusions: The neuroblastoma component proved to be more aggressive than the other elements of this neoplasm. This finding suggests that mixed germ cell tumors showing a large neuroblastoma component should be treated promptly and aggressively with chemotherapy.