title: Morphologic and immunohistochemical characterization of Leydig cell tumor variants in Wistar rats.
abstract: During a routine long-term drug safety study, lasting approximately 2 1/2 yr, male Wistar rats, treated with a prolactin-inhibiting compound, developed an excess of Leydig cell tumors (LCTs). Most tumors were typical for the rat but a small number showed an unusual variation and some appeared malignant. The variation consisted of glandular and/or tubular structures within the tumor mass which occasionally anastomosed and contained an eosinophilic periodic-acid Schiff (PAS) positive material. In a few of these variants, malignant features such as cellular atypia, capsular, and lymphatic invasion and necrosis were seen. No metastases were detected. Detailed morphological and immunohistochemical investigations were conducted in order to establish the cell of origin of these variants. Glandular/tubular structures were found to stain with varying intensity for vimentin and cytokeratin, but were always negative for beta-tubulin. The results indicated that the cell of origin of these LCT variants was indeed the Leydig cell and that glandular and/or tubular structures within LCTs represented a form of Leydig cell metaplasia.
authors.affiliation: Sandoz Pharma Ltd., Drug Safety Assessment/Toxicology, Basle, Switzerland.
authors.forename: S R
authors.initials: SR
authors.lastname: Qureshi
authors.forename: E
authors.initials: E
authors.lastname: Perentes
authors.forename: R A
authors.initials: RA
authors.lastname: Ettlin
authors.forename: M
authors.initials: M
authors.lastname: Kolopp
authors.forename: D E
authors.initials: DE
authors.lastname: Prentice
authors.forename: A
authors.initials: A
authors.lastname: Frankfurter
mesh_terms: D000818:Animals; D000906:Antibodies; D002471:Cell Transformation, Neoplastic; D004744:Enkephalin, Methionine / Q000032:analysis; D000939:Epitopes / Q000032:analysis; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D007150:Immunohistochemistry; D007633:Keratins / Q000276:immunology; D007984:Leydig Cell Tumor / Q000737:chemistry / Q000473:pathology*; D008297:Male; D010751:Phosphopyruvate Hydratase / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D009418:S100 Proteins / Q000032:analysis; D012708:Sertoli Cells / Q000737:chemistry / Q000166:cytology; D013373:Substance P / Q000032:analysis; D016708:Synaptophysin / Q000032:analysis; D013736:Testicular Neoplasms / Q000737:chemistry / Q000473:pathology*; D014404:Tubulin / Q000032:analysis
chemical_list: D000906:Antibodies; D000939:Epitopes; D005904:Glial Fibrillary Acidic Protein; D009418:S100 Proteins; D016708:Synaptophysin; D014404:Tubulin; D013373:Substance P; D004744:Enkephalin, Methionine; D007633:Keratins; D010751:Phosphopyruvate Hydratase