Primary central nervous system (CNS) lymphomas are rare in humans and even more uncommon in animals. We report the clinical, pathological and immunohistochemical features of a presumptive primary cerebral T-cell lymphoma (PCTCL) in an aged female white-tailed deer (Odocoileus virginianus) that had chronic progressive neurological disease characterized by ataxia, claudication and eventual circling. The animal was euthanized due to poor prognosis. Grossly, a 2.5 cm dark red, friable nodule effaced the cortical neuroparenchyma of the left anterior cingulate cortex (LACC). Microscopically, the meningeal vasculature and adjacent grey and white matter cortical neuroparenchyma of the LACC were infiltrated by a poorly demarcated, unencapsulated and densely cellular round cell neoplasm with a consistent angiocentric pattern. The neoplasm was associated with extensive regions of haemorrhage and liquefactive necrosis. Neoplastic cells immunolabelled for CD3 antigen and had high proliferative activity, as indicated by Ki-67 labelling. Based on the cytohistomorphological and immunohistochemical features and absence of metastasis, a diagnosis of PCTCL was determined. This case indicates that PCTCL should be considered in the differential diagnosis of neurological disease and intracranial, intra-axial CNS masses in deer.

原发性中枢神经系统 (CNS) 淋巴瘤在人类中很少见，在动物中更为罕见。我们报告了一头老年雌性白尾鹿（Odocoileus virginianus）疑似原发性脑 T 细胞淋巴瘤（PCTCL）的临床、病理和免疫组织化学特征) 患有以共济失调、跛行和最终盘旋为特征的慢性进行性神经系统疾病。由于预后不良，该动物被安乐死。大体上，一个 2.5 厘米深红色易碎结节抹去了左前扣带回皮层 (LACC) 的皮质神经实质。在显微镜下，LACC 的脑膜脉管系统和相邻的灰质和白质皮质神经实质被界限不清、未包裹且细胞密集的圆形细胞肿瘤浸润，具有一致的血管中心模式。肿瘤与大面积的出血和液化性坏死有关。肿瘤细胞对 CD3 抗原进行免疫标记并具有高增殖活性，如 Ki-67 标记所示。基于细胞组织形态学和免疫组化特征以及无转移，确定了 PCTCL 的诊断。本病例提示在与鹿的神经系统疾病和颅内、轴内CNS肿块的鉴别诊断中应考虑PCTCL。