Chapman Seth, Nabity Mary, Calise David
Texas Veterinary Medical Center, Department of Veterinary Pathobiology, Texas A&M University, College Station, TX 77842, USA.
Vet Clin Pathol. 2008 Mar;37(1):133-9. doi: 10.1111/j.1939-165X.2008.00018.x.
A 3.5-year-old female spayed Rat Terrier was presented for evaluation of a submucosal lingual mass. Fine-needle aspiration of the mass revealed a population of neoplastic cells composed predominantly of small, round cells and large, round to spindle-shaped cells, which occasionally had blunt cytoplasmic borders and multiple nuclei. The neoplastic cells had moderate to marked anisocytosis and anisokaryosis. The cytologic interpretation was malignant neoplasia, most likely sarcoma. Histopathologic examination of a biopsy specimen revealed an unencapsulated, poorly demarcated, moderately cellular neoplasm composed of individualized, infiltrative spindle cells. Elongate skeletal muscle cells with prominent, rectangular borders (strap cells) were observed. A morphologic diagnosis of rhabdomyosarcoma was made. Staining with phosphotungstic acid-hematoxylin revealed haphazardly arranged skeletal muscle cross-striations. Immunohistochemical staining results for vimentin, Myo D1, desmin, and myoglobin were positive, though staining intensity of tumor cells varied with the degree of differentiation. Using transmission electron microscopy, irregular, disorganized Z-bands were identified. Rhabdomyosarcomas are uncommon tumors in the dog, and rarely may involve the tongue or oral cavity. Cytologic evaluation of a rhabdomyosarcoma may reveal a pleomorphic population of cells and definitive diagnosis may require histologic examination, immunohistochemical staining, and electron microscopy.
一只3.5岁已绝育的雌性大鼠梗犬因舌黏膜下肿物前来评估。对肿物进行细针穿刺抽吸，发现一群肿瘤细胞，主要由小的圆形细胞和大的圆形至梭形细胞组成，这些细胞偶尔有钝圆的细胞质边界和多个细胞核。肿瘤细胞有中度至明显的细胞大小不等和核大小不等。细胞学诊断为恶性肿瘤，很可能是肉瘤。对活检标本进行组织病理学检查，发现一个无包膜、边界不清、细胞中度密集的肿瘤，由单个的、浸润性的梭形细胞组成。观察到有突出的矩形边界的细长骨骼肌细胞（束状细胞）。做出横纹肌肉瘤的形态学诊断。磷钨酸苏木精染色显示骨骼肌横纹排列紊乱。波形蛋白、肌分化抗原1（Myo D1）、结蛋白和肌红蛋白的免疫组织化学染色结果均为阳性，不过肿瘤细胞的染色强度随分化程度而异。使用透射电子显微镜，发现了不规则、无序的Z带。横纹肌肉瘤在犬中是罕见肿瘤，很少累及舌或口腔。横纹肌肉瘤的细胞学评估可能显示细胞多形性，明确诊断可能需要组织学检查、免疫组织化学染色和电子显微镜检查。
