title: Hematogenous metastasis of embryonal rhabdomyosarcoma originating from skeletal muscle in a young dog.
abstract: An 8-month-old, intact male Golden Retriever with a history of left forelimb lameness for 2 months was presented to the Veterinary Medical Teaching Hospital of Konkuk University (Seoul, Korea). Results of a physical examination revealed a mass in the left axillary region. A thoracic radiography showed an osteolytic lesion in the scapula and the presence of a soft tissue density from the thoracic wall to the scapula. A computerized tomography revealed a mass invading into the scapula, and small nodules in the lung that suggested metastasis. At necropsy, a pale-yellow, irregular, firm, 8 x 10 x 5 cm mass extended from axillary region and destroyed the scapular. In addition, small nodules were noted in the lung. On microscopic examination, the mass consisted of round-to-oval cells, with eccentrically located hyperchromatic nuclei and eosinophilic cytoplasm in fibromyxoid stroma. Tumor cells were observed in blood vessels in the primary mass. Tumor cells strongly expressed vimentin, desmin, and myoglobin. In phosphotungstic acid-hematoxylin staining, cross-striations were detected in rhabdomyoblasts. In periodic acid-Schiff reaction, only a few cells were detected. The diagnosis was primary rhabdomyosarcoma of the appendicular muscle of a young dog. The tumor presumably originated in the skeletal muscle of the limb, invaded into the adjacent scapular bone, and metastasized to the lung.
authors.affiliation: Department of Veterinary Pathobiology, Small Animal Tumor Diagnostic Center, College of Veterinary Medicine, Konkuk University, no. 1 Hwayang-dong, Kwangjin-ku, Seoul 143-701, Korea.
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Yhee
authors.forename: Dae-Hyun
authors.initials: DH
authors.lastname: Kim
authors.forename: Du-Na
authors.initials: DN
authors.lastname: Hwang
authors.forename: Chang-Taek
authors.initials: CT
authors.lastname: Moon
authors.forename: Chi-Ho
authors.initials: CH
authors.lastname: Yu
authors.forename: Hwi-Yool
authors.initials: HY
authors.lastname: Kim
authors.forename: Alan R
authors.initials: AR
authors.lastname: Doster
authors.forename: Jung-Hyang
authors.initials: JH
authors.lastname: Sur
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D017809:Fatal Outcome; D007150:Immunohistochemistry / Q000662:veterinary; D008175:Lung Neoplasms / Q000556:secondary / Q000662:veterinary*; D008297:Male; D019042:Muscle Neoplasms / Q000473:pathology / Q000662:veterinary*; D018233:Rhabdomyosarcoma, Embryonal / Q000473:pathology / Q000662:veterinary*; D014057:Tomography, X-Ray Computed / Q000662:veterinary