title: Oral squamous cell carcinoma in a pigtailed macaque (Macaca nemestrina).
abstract: An adult, gravid, female pigtailed macaque (Macaca nemestrina) presented for facial swelling centered on the left mandible that was approximately 5 cm wide. Differential diagnoses included infectious, inflammatory, and neoplastic origins. Definitive antemortem diagnosis was not possible, and the macaque's condition worsened despite supportive care. Necropsy findings included a mandibular mass that was locally invasive and expansile, encompassing approximately 80% of the left mandibular bone. The mass replaced portions of the soft palate, hard palate, sinuses, ear canal, and the caudal-rostral calvarium and masseter muscle. Histologically, the mass was a neoplasm that was poorly circumscribed, unencapsulated, and infiltrative invading regional bone and soft tissue. The mass consisted of polygonal squamous epithelial cells with intercellular bridging that breached the epithelial basement membrane and formed invasive nests, cords, and trabeculae. The mitotic rate averaged 3 per 400× field of view, with occasional bizarre mitotic figures. Epithelial cells often exhibited dyskeratosis, and the nests often contained compact lamellated keratin (keratin pearls). The neoplasm was positive via immunohistochemistry for pancytokeratin, variably positive for S100, and negative for vimentin, smooth muscle actin, and desmin. The gross, histologic, and immunohistochemical findings were consistent with an aggressive oral squamous cell carcinoma. The neoplasm was negative via PCR for papilloma virus. In general, neoplasia in macaques is rare. Although squamous cell carcinomas are one of the most common oral neoplasia in many species, to our knowledge this case represents the first reported oral squamous cell carcinoma in a pigtailed macaque.
authors: Washington National Primate Research Center, Seattle Children's Research Institute, Seattle, Washington, USA; Valley Biosystems, West Sacramento, California, USA. destockinger@gmail.com.
authors: Diane E
authors: DE
authors: Stockinger
authors: Washington National Primate Research Center, Seattle Children's Research Institute, Seattle, Washington, USA.
authors: Derek L
authors: DL
authors: Fong
authors: Washington National Primate Research Center, Seattle Children's Research Institute, Seattle, Washington, USA.
authors: Keith W
authors: KW
authors: Vogel
authors: Washington National Primate Research Center, Seattle Children's Research Institute, Seattle, Washington, USA.
authors: W McIntyre
authors: WM
authors: Durning
authors: Washington National Primate Research Center, Seattle Children's Research Institute, Seattle, Washington, USA.
authors: Anne E
authors: AE
authors: Torrence
authors: Department of Pediatrics, Division of Infectious Diseases, Center for Childhood Infections and Prematurity Research, Seattle Children's Research Institute, Seattle, Washington, USA.
authors: Timothy M
authors: TM
authors: Rose
authors: Center for Childhood Infections and Prematurity Research, Seattle Children's Research Institute, Seattle, Washington, USA.
authors: Jeannette P
authors: JP
authors: Staheli
authors: Washington National Primate Research Center, Seattle Children's Research Institute, Seattle, Washington, USA.
authors: Audrey
authors: A
authors: Baldessari
authors: Washington National Primate Research Center, Department of Comparative Medicine, University of Washington, Seattle Children's Research Institute, Seattle, Washington, USA.
authors: Robert D
authors: RD
authors: Murnane
authors: Department of Comparative Medicine, University of Washington, Seattle Children's Research Institute, Seattle, Washington, USA.
authors: Renee R
authors: RR
authors: Hukkannen
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000662:veterinary*; D017809:Fatal Outcome; D005260:Female; D007150:Immunohistochemistry / Q000662:veterinary; D007633:Keratins / Q000378:metabolism; D008254:Macaca nemestrina; D008992:Monkey Diseases / Q000473:pathology*; D009062:Mouth Neoplasms / Q000473:pathology / Q000662:veterinary*
chemical_list: D007633:Keratins