title: Fusocellular gonadal stromal tumour of the testis with epithelial and myoid differentiation.
abstract: We describe an unusual fusocellular gonadal stromal tumour with a benign behaviour in the left testis from a 16-year-old man. The neoplasm consisted of a non-encapsulated proliferation of irregularly arranged, fusiform cell bundles in fibrous connective tissue. The tumour cells contained a slightly infolded nucleus, some dilated rough endoplasmic reticulum cisternae, abundant filament bundles which connected to subplasmalemmal electron-dense bodies, pinocytotic vesicles and a discontinuous basal lamina. The intercellular spaces were narrow and the tumour cells were joined by desmosomes. These cells were immunoreactive for muscle actin, alpha-actinin and vimentin. Focal immunostaining for collagen type IV was observed around the cells. No immunoreactivity for keratins, desmin S-100 protein or XIIIa factor was found. The findings suggest that the tumour arose from the peritubular myoid cells.
authors.affiliation: Department of Morphology, School of Medicine, Autonomous University of Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Nistal
authors.forename: A
authors.initials: A
authors.lastname: Puras
authors.forename: C
authors.initials: C
authors.lastname: Perna
authors.forename: R
authors.initials: R
authors.lastname: Guarch
authors.forename: R
authors.initials: R
authors.lastname: Paniagua
mesh_terms: D000199:Actins / Q000032:analysis / Q000276:immunology; D000293:Adolescent; D003896:Desmosomes / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D018312:Sex Cord-Gonadal Stromal Tumors / Q000737:chemistry / Q000473:pathology* / Q000648:ultrastructure; D013736:Testicular Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000648:ultrastructure; D014746:Vimentin / Q000032:analysis / Q000276:immunology
chemical_list: D000199:Actins; D014746:Vimentin