title: Multicentric cutaneous neuroendocrine (Merkel cell) carcinoma in a dog.
abstract: Multicentric cutaneous neuroendocrine (Merkel cell) carcinoma was diagnosed in a 5-year-old castrated male Keeshond dog with multiple firm nodular cutaneous masses. The neoplastic tissue locally effaced the periadnexal and deep dermis and consisted of densely cellular confluent clusters of round to polygonal cells supported by a delicate fibrovascular stroma. The cells were moderately immunoreactive with chromogranin A, synaptophysin, and cytokeratin. Ultrastructurally, the cells had characteristic membrane-bound dense-core neuroendocrine granules approximately 120 nm in diameter and randomly dispersed throughout the cytoplasm. Effacement of dermal structures and multicentric distribution suggested low-grade malignant phenotype. These findings contrast with the typical benign behavior of canine cutaneous neuroendocrine tumors.
authors.affiliation: Department of Pathobiology, 166 Greene Hall, College of Veterinary Medicine, Auburn University, Auburn, AL 36849-5519, USA. bessiks@auburn.edu
authors.forename: K S
authors.initials: KS
authors.lastname: Joiner
authors.forename: A N
authors.initials: AN
authors.lastname: Smith
authors.forename: R A
authors.initials: RA
authors.lastname: Henderson
authors.forename: W R
authors.initials: WR
authors.lastname: Brawner
authors.forename: E A
authors.initials: EA
authors.lastname: Spangler
authors.forename: E A
authors.initials: EA
authors.lastname: Sartin
mesh_terms: D000818:Animals; D015266:Carcinoma, Merkel Cell / Q000473:pathology / Q000648:ultrastructure / Q000662:veterinary*; D053379:Chromogranin A / Q000378:metabolism; D004283:Dog Diseases / Q000378:metabolism / Q000473:pathology*; D004285:Dogs; D017809:Fatal Outcome; D007633:Keratins / Q000378:metabolism; D008297:Male; D012867:Skin / Q000473:pathology; D012878:Skin Neoplasms / Q000473:pathology / Q000648:ultrastructure / Q000662:veterinary*; D016708:Synaptophysin / Q000378:metabolism
chemical_list: D053379:Chromogranin A; D016708:Synaptophysin; D007633:Keratins