title: Poorly differentiated carcinoma of the parotid gland in a six-week-old Sprague-Dawley rat.
abstract: A poorly differentiated spontaneous tumor was found in the parotid gland region of a 6-wk-old female Sprague-Dawley rat. The tumor consisted of undifferentiated cells forming dense clusters, well-defined nests, or compact sheets. In some areas, spindle-shaped cells were arranged in a fascicular fashion. Neither ductular nor acinar structures were seen. No keratinization was observed, either. Mitotic figures were frequent. All neoplastic cells were immunoreactive for pankeratin but negative for vimentin, alpha-smooth muscle actin and S-100 protein. Ultrastructurally, the tumor cells were characterized by desmosome-like junctional complexes, poorly developed cytoplasmic organelles, and microvilli-like cytoplasmic processes. Based on these findings and its anatomical location, the present tumor was diagnosed as a poorly differentiated carcinoma of the parotid gland.
authors.affiliation: Department of Experimental Pathology, Kawanishi Pharma Research Institute, Nippon Boehringer Ingelheim Co., Ltd., Japan.
authors.forename: I
authors.initials: I
authors.lastname: Tsunenari
authors.forename: J
authors.initials: J
authors.lastname: Yamate
authors.forename: S
authors.initials: S
authors.lastname: Sakuma
mesh_terms: D000818:Animals; D002277:Carcinoma / Q000473:pathology* / Q000648:ultrastructure / Q000662:veterinary*; D002454:Cell Differentiation; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D010307:Parotid Neoplasms / Q000473:pathology* / Q000648:ultrastructure / Q000662:veterinary*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012376:Rodent Diseases / Q000473:pathology*