title: Thymic Carcinoma with Cartilage Formation in a Dog.
abstract: An 11-year-old female Chihuahua exhibited respiratory distress and a computed tomography scan showed a large mass in the anterior thoracic cavity. During surgery, it was found that the mass was strongly adherent to surrounding tissue. A histopathological examination of a biopsy sample from the mass revealed proliferation of atypical epithelial cells and cartilage formation admixed with mature lymphocytes. Immunohistochemically, the tumour cells, as well as the normal canine thymic epithelial cells, were positive for pan-cytokeratin (CK), CK5/6, CK19, p63 and bone morphogenetic protein (BMP) 6. Foci of cartilage tissue were formed in association with the neoplastic epithelial tissue. In the normal canine thymus, the subcapsular epithelial cells are positive for both CK19 and BMP6. These findings indicate that the cartilage element within the tumour developed from CK19-positive neoplastic epithelial cells, which were derived from the thymic subcapsular epithelium. This case represents a novel variant of canine thymic epithelial tumour that exhibits cartilage differentiation.
authors.affiliation: Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, Japan.
authors.forename: J K
authors.initials: JK
authors.lastname: Chambers
authors.affiliation: Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshino
authors.affiliation: Veterinary Medical Center, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Fujiwara
authors.affiliation: Department of Veterinary Surgery, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Nishimura
authors.affiliation: Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nakayama
authors.affiliation: Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, Japan. Electronic address: auchidak@mail.ecc.u-tokyo.ac.jp.
authors.forename: K
authors.initials: K
authors.lastname: Uchida
mesh_terms: D000818:Animals; D002356:Cartilage / Q000473:pathology*; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D005260:Female; D009375:Neoplasms, Glandular and Epithelial / Q000662:veterinary*; D013953:Thymus Neoplasms / Q000662:veterinary*
keywords: cartilage; dog; thymic carcinoma; thymic epithelial cell