Malignant neoplasm of the perineural sheath retrobulbar and intracranial in dog: case report

ABSTRACT Tumors of the perineural sheath are uncommon in domestic animals. We report the case of a 5-year-old female dog with a history of increased volume in the retrobulbar region of the right eye (RE) three weeks ago. The clinical examination revealed a presence of a right retrobulbar neoformation with cranial ocular globe displacement. In the examinations carried out during hospitalization, it was not possible to locate a source and an extension of the neoformation. The animal died of cardiorespiratory arrest and was referred to an autopsy. The macroscopic evaluation revealed a whitish neoformation fixated to the base of the skull in a seal region, with a possible non-III origin of cranial nerves, infiltrating non-encephalon at the height of the hypothalamus, extending caudally towards the brainstem and cranially to the orbit right, compressing RE. Microscopically it consisted of short bundles intertwined or enovelados of spindle cells with discrete to moderate pleomorphism, alternating to areas of multifocal necrosis, compatible with tumor of the perineural sheath. Immunohistochemical examination showed weak marking for S100 and GFAP and positive marking for vimentin, indicating malignancy.

摘要
神经周鞘（perineural sheath）肿瘤在伴侣动物中较为罕见。本研究报告1例5岁雌性犬，三周前出现右眼（RE）右侧球后区域肿胀。临床检查可见右侧球后存在新生物，伴眼球向颅侧移位。住院期间开展的各项检查均无法明确该新生物的起源与侵袭范围。该犬最终因心搏骤停死亡，随后接受尸体剖检。大体标本检查可见一乳白色新生物，附着于颅底seal区域，推测其起源非第Ⅲ对颅神经，于下丘脑水平浸润非脑组织，向尾侧延伸至脑干，向颅侧延伸至右侧眼眶，压迫右眼（RE）。镜下观察可见梭形细胞形成短束，相互交织排列，伴轻度至中度多形性，与多灶性坏死区域交替分布，符合神经周鞘肿瘤的病理特征。免疫组织化学检查显示S100与胶质纤维酸性蛋白（GFAP）呈弱阳性表达，波形蛋白（vimentin）呈阳性表达，提示肿瘤具有恶性特征。