title: Spontaneous malignant mixed Müllerian tumor in a Wistar rat: a case report including immunohistochemistry.
abstract: This report presents a rare, spontaneous, heterologous, malignant mixed Müllerian tumor observed in a 98-week-old untreated Wistar rat. At necropsy, the right uterine horn was dilated and contained a mass of approximately 10 × 15 mm. Histopathologically the mass consisted of 2 parts with different morphologic characteristics, a polypoid mass protruding into the uterine lumen and a more solid part that replaced the adjacent uterine wall. The solid part exhibited characteristics of a highly infiltrative adenocarcinoma, whereas the composition of the polypoid mass was heterogeneous, consisting of a variety of benign and malignant epithelial and mesenchymal elements. The epithelial components included well-differentiated endometrial and squamous epithelium juxtaposed to carcinosarcomatous areas. The mesenchymal components consisted of well-differentiated cartilage and bone along with chondrosarcomatous, rhabdomyomatous, and other mesenchymal elements. Immunohistochemical analysis further supported the diagnosis of malignant mixed Müllerian tumor.
authors.affiliation: Pathology Group, Department of Toxicology, NOTOX B.V., P.O. Box 3476, 5203 DL's-Hertogenbosch, The Netherlands. hetty.van.den.brink@notox.nl
authors.forename: H
authors.initials: H
authors.lastname: van den Brink-Knol
authors.forename: E
authors.initials: E
authors.lastname: van Esch
mesh_terms: D000818:Animals; D000830:Animals, Laboratory / Q000033:anatomy & histology; D005260:Female; D018200:Mixed Tumor, Mullerian / Q000473:pathology / Q000662:veterinary*; D051381:Rats; D017208:Rats, Wistar / Q000033:anatomy & histology; D014594:Uterine Neoplasms / Q000473:pathology / Q000662:veterinary*; D014599:Uterus / Q000473:pathology