Visual Disturbances in a Case of Tentorium Hypoplasia Associated with Migrational Abnormality (S53.006)

Objective: To present the first case of Tentorium Hypoplasia associated with visual disturbance. Background: During developmental stage 14 (week 5) the medial parts of the tentorium develop first from the prechordal plate followed by development of the lateral parts. The medial parts involute and the lateral parts consisting of the caudo-lateral and rostro-lateral parts fuse. Abnormal fusion of the lateral parts can lead to agenesis or hypoplasia of the tentorium. Tentorium hypoplasia is generally asymptomatic. Tanaka et al reported a case of tentorial agenesis leading to temporal lobe herniation causing trigeminal neuralgia. Visual disturbance associated with tentorium hypoplasia has not been described. Design/Methods: 42-year-old woman presented with blurry vision in her left visual field since childhood. Whenever she focused on reading, she would develop band-like pressure headaches lasting 2–3 hours in duration. No history of trauma, ischemic events or migraine was reported. Results: Formal visual field testing showed left homonymous hemianopia with more prominent left homonymous inferior quadrantanopia. The optic disc and central vision was normal. MRI brain revealed partial hypoplasia of the superior aspect of the right tentorium cerebelli with medial and inferior herniation of portions of the right temporal and occipital lobe including the cuneus. There was abnormal sulcation and gyration in the right temporal occipital region reflecting the presence of an associated migrational abnormality. MRI did not reveal ischemic changes. Diffusion Tensor Imaging with tractography revealed that a portion of the white matter in the herniated tissue appears to represent some of the visual pathway tracts/optic radiation and visual cortex. Conclusions: Tentorium Hypoplasia is rarely associated with symptoms. In our case herniation of the anterior cuneus through the tentorial defect in combination with a congenital migrational anomaly led to a symptomatic visual field defect. This constellation of findings has not been previously described in the literature. Disclosure: Dr. Kurian has nothing to disclose. Dr. Iqbal has nothing to disclose. Dr. Zisman has nothing to disclose. Dr. Sun has nothing to disclose. Dr. Tenner has nothing to disclose. Dr. Mehta has nothing to disclose. Dr. Bobra has nothing to disclose. Dr. Ahluwalia-Singh has nothing to disclose. Dr. Thomas has nothing to disclose.