title: Subcutaneous malignant mast cell tumor in a Japanese macaque (Macaca fuscata).
abstract: The histopathological, immunohistochemical, and ultrastructural morphologic characteristics of a tumor in the subcutaneous tissue of the chest of a 19-year-old female Japanese macaque were investigated. Consequently, the mass was diagnosed as a malignant mast cell tumor (MCT). Tumors were present in both mammary gland portions of the anterior thorax. Both tumors showed the same histopathological findings. The tumor tissue was defined by the presence of delicate connective tissue, and the tumor cells grew in a cord-like or cobblestone pattern. The tumor cell cytoplasm was very clear. The nuclei were relatively uniform and the cells showed a low nucleus-cytoplasm ratio. The cytoplasmic granules stained blue with Alcian blue and eosinophils had infiltrated into the tumor tissue. Furthermore, immunohistochemical analysis revealed that the tumor cell membrane was positive for the anti-c-kit antibody. In ultrastructural morphologic analyses, all tumor cells showed a rich cytoplasm and, occasionally, granules wrapped in a limiting membrane of high electron density. The tumor cells had metastasized to the axillary lymph nodes, the kidney, and the peritoneum. Based on these results, the mass was diagnosed as a malignant MCT originating from the subcutaneous tissue of the chest. Since cases of MCTs in macaques are very rare, this report presents important new knowledge of neoplastic lesions in this species.
authors.affiliation: Laboratory of Veterinary Pathology, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Tsugo
authors.affiliation: Laboratory of Veterinary Pathology, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan.
authors.forename: Tomoe
authors.initials: T
authors.lastname: Kinoshita
authors.affiliation: Laboratory of Veterinary Pathology, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Kadowaki
authors.affiliation: Laboratory of Veterinary Pathology, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan.
authors.forename: Go
authors.initials: G
authors.lastname: Sugahara
authors.affiliation: Gunma Safari Park, 1 Okamoto, Tomioka, Gunma, 370-2300, Japan.
authors.forename: Emiko
authors.initials: E
authors.lastname: Saito
authors.affiliation: Gunma Safari Park, 1 Okamoto, Tomioka, Gunma, 370-2300, Japan.
authors.forename: Shigehisa
authors.initials: S
authors.lastname: Kawakami
authors.affiliation: Laboratory of Veterinary Pathology, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan. une@azabu-u.ac.jp.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Une
mesh_terms: D000818:Animals; D005260:Female; D007680:Kidney Neoplasms / Q000556:secondary / Q000662:veterinary; D008251:Macaca; D008407:Mast Cells / Q000473:pathology*; D008415:Mastocytosis / Q000473:pathology / Q000556:secondary / Q000662:veterinary*; D008992:Monkey Diseases / Q000473:pathology*; D010534:Peritoneal Neoplasms / Q000556:secondary / Q000662:veterinary; D040521:Subcutaneous Tissue / Q000473:pathology; D013899:Thoracic Neoplasms / Q000473:pathology / Q000556:secondary / Q000662:veterinary*
keywords: Japanese macaque; Mast cell tumor; Metastasis; Spontaneous; Subcutaneous