Extranodal lymphoma in a bush dog (Speothos venaticus) - case report

ABSTRACT A captive 7-year-old male bush dog (Speothos venaticus) was diagnosed with lymphoma affecting the kidneys, adrenal glands, liver, and spleen. The animal developed renal failure and was euthanized due to poor prognosis. Grossly, both kidneys were enlarged with multiple nodules. Histologically, the neoplasm was an infiltrative and poorly demarcated round cell tumor. Two morphologically distinct cell populations were observed, smaller cells with a lymphocytic morphology, and another population of larger and pleomorphic cells. Most of the smaller cell population, approximately 40% of the population within the neoplasm, were CD3 positive. Neoplastic cells were CD45, CD11d, and granzime B positive, and negative for CD20, CD79a, PAX5, CD163, and myeloperoxidase. This is the first reported case of lymphoma in a bush dog. This report demonstrated the suitability of several cell surface markers for differential diagnosis of round cell tumors in this species.

摘要 一只圈养的7岁雄性薮犬（Speothos venaticus）被诊断患有累及肾脏、肾上腺、肝脏及脾脏的淋巴瘤。该动物出现肾衰竭，因预后不良被实施安乐死。大体检查可见双侧肾脏肿大，且存在多发结节。组织病理学检查显示，该肿瘤为浸润性、边界不清的圆形细胞肿瘤。镜下可见两种形态学特征迥异的细胞群：一类为具有淋巴细胞形态的小型细胞，另一类为体积更大且具有多形性的细胞。该肿瘤内约40%的细胞为小型细胞群，其中大部分呈CD3阳性。肿瘤细胞呈CD45、CD11d及颗粒酶B阳性，而CD20、CD79a、PAX5、CD163及髓过氧化物酶呈阴性。本研究为首例薮犬淋巴瘤的报道，同时证实了多种细胞表面标志物可用于该物种圆形细胞肿瘤的鉴别诊断。