Fine Needle Aspiration and Core Biopsy Specimens: Germ Cell Neoplasms

Abstract

While core biopsy and FNA are not typically performed directly on testicular masses, the diagnosis of germ cell neoplasms can occur in locations other than the testis or genitourinary tract, such as the mediastinum and retroperitoneum. These extratesticular lesions are histologically and cytomorphologically indistinguishable from those arising in the testes. While some entities such as seminoma occasionally demonstrate distinctive cytomorphologic features, the use of immunohistochemical stains is often required to determine the presence of seminomatous and/or non-seminomatous components and can also be used to identify specific components present within a mixed germ cell tumor. This chapter covers the diagnosis of germ cell neoplasms on small biopsy and fine needle aspiration specimens.