An 88.5 cm long, 12.9 kg, 3-week-old stranded male Atlantic harbour seal (Phoca vitulina concolor) presented with cerebellar ataxia, delayed postural reactions, hyperaesthesia and nystagmus. The skull was enlarged and domed. Ultrasound through a persistent fontanelle in the frontal bone revealed hydrocephalus. Magnetic resonance imaging showed diffuse enlargement of the ventricular system, an absent cerebellar vermis, hypertrophy of the choroid plexus of the fourth ventricle and enlargement of the caudal fossa. Throughout rehabilitation, the seal failed to achieve milestones critical for successful release or placement in a managed care facility, including the ability to feed independently and haul out. Three months into rehabilitation it began to regurgitate and staff had difficulty administering food to the seal. The seal was euthanized due to a poor prognosis. Post-mortem examination confirmed a) aplasia of the dorsal cerebellar vermis and hypoplasia of the most dorsal portions of the right and left cerebellar hemispheres, b) severe, diffuse, congenital communicating hydrocephalus, and c) aplasia of the interthalamic adhesion and corpus callosum. This case represents the first report of Dandy–Walker-like malformation (DWLM) in a marine mammal and illustrates the importance of advanced imaging and thorough post-mortem examination in free-ranging pinnipeds that strand with evidence of neurological disease.

一只长88.5厘米，重12.9千克，三周大的搁浅雄性大西洋海豹（Phoca vitulina concolor）表现为小脑性共济失调，姿势反应迟缓，感觉过敏和眼球震颤。颅骨扩大并呈圆顶状。通过额骨持续font门超声检查发现脑积水。磁共振成像显示脑室系统弥漫性增大，小脑ver骨缺失，第四脑室脉络丛肥大和尾窝增大。在整个康复过程中，海豹没有达到成功释放或放置在托管式护理设施中的关键里程碑，包括独立进食和牵引的能力。康复三个月后，它开始反流，工作人员难以管理海豹的食物。由于预后不良，因此对安乐死实施了安乐死。验尸证实a）小脑背侧a部发育不全，小脑左右半部大部分背侧发育不全，b）先天性严重，弥漫性先天性沟通性脑积水，c）丘脑间粘连和体发育不全。该病例代表了海洋哺乳动物中第一个类似丹迪·沃克的畸形（DWLM）的报道，并说明了先进的成像和彻底的验尸检查对于散发有神经系统疾病证据的自由散发的nip的重要性。