title: Clinical and Pathologic Study of Feline Merkel Cell Carcinoma With Immunohistochemical Characterization of Normal and Neoplastic Merkel Cells.
abstract: The authors herein describe the morphologic and immunohistochemical features of normal Merkel cells as well as the clinicopathologic findings of Merkel cell carcinoma in cats. Merkel cells were characterized as vacuolated clear cells and were individually located in the epidermal basal layer of all regions examined. Clusters of Merkel cells were often observed adjacent to the sinus hair of the face and carpus. Immunohistochemically, Merkel cells were positive for cytokeratin (CK) 20, CK18, p63, neuron-specific enolase, synaptophysin, and protein gene product 9.5. Merkel cell carcinoma was detected as a solitary cutaneous mass in 3 aged cats (13 to 16 years old). On cytology, large lymphocyte-like cells were observed in all cases. Histologic examinations of surgically resected tumors revealed nests of round cells separated by various amounts of a fibrous stroma. Tumor cells were commonly immunopositive for CK20, CK18, p63, neuron-specific enolase, and synaptophysin, representing the characteristics of normal Merkel cells.
authors: Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors: A
authors: A
authors: Dohata
authors: Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan achamber@mail.ecc.u-tokyo.ac.jp.
authors: J K
authors: JK
authors: Chambers
authors: Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors: K
authors: K
authors: Uchida
authors: Bin Animal Clinic, Miyazaki, Japan.
authors: S
authors: S
authors: Nakazono
authors: Iwakuni Health and Welfare Center, Yamaguchi, Japan.
authors: Y
authors: Y
authors: Kinoshita
authors: Japan Animal Referral Medical Center, Kanagawa, Japan.
authors: K
authors: K
authors: Nibe
authors: Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors: H
authors: H
authors: Nakayama
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis*; D015266:Carcinoma, Merkel Cell / Q000473:pathology / Q000662:veterinary*; D002371:Cat Diseases / Q000473:pathology*; D002415:Cats; D005260:Female; D007633:Keratins / Q000032:analysis; D008297:Male; D018862:Merkel Cells / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D010751:Phosphopyruvate Hydratase / Q000032:analysis; D012878:Skin Neoplasms / Q000473:pathology / Q000662:veterinary*; D016708:Synaptophysin / Q000032:analysis
chemical_list: D014408:Biomarkers, Tumor; D016708:Synaptophysin; D007633:Keratins; D010751:Phosphopyruvate Hydratase
keywords: Merkel cell; Merkel cell carcinoma; cat; cytology; immunohistochemistry; lymphoma; neuroendocrine carcinoma