Ventral Foramen Magnum Neurenteric Cysts: Case Series and Review of Literature

Introduction: Neurenteric cysts are uncommon, benign, and congenital lesions. Foramen magnum location is very rare. Authors report four cases of neurenteric cyst at the foramen magnum situated ventral to the cervicomedullary junction, all managed surgically. The difficulties in diagnosis and management are discussed along with review of the pertinent literature. Material and Methods: Retrospective chart review of patients diagnosed and operated from 2010 to 2013 with a diagnosis of ventral foramen magnum neurenteric cyst. Results: Mean age group was 27.5 years (range, 14-55 years). Male:female ratio was 3:1. Mean duration of presentation was 7 months (range, 4-12 months). Presenting symptoms were: suboccipital pain (n = 3), LCN paresis (n = 2), long tract signs (n = 1), and gait ataxia (n= 1). Mean size of the cyst was 2.8 cm (1.7-4.8 cm). Lesions were hypointense and hyperintense on T1WI in one and three cases, respectively. The surgical approaches utilized were: lateral suboccipital (n = 1), far lateral (n = 2), and retromastoid (n = 1). Thick milky and gelatinous contents were seen in two cases each. Near-total excision was performed in three cases while marsupialization was done in a single case. Mean follow-up was 16.5 months (3-36 months). Conclusions: Foramen magnum neurenteric cysts are rare, benign tumors of central nervous system. Exact preoperative diagnosis can usually be established with MRI. Surgical removal is the treatment of choice. Complete excision can rarely be achieved and must not be attempted aggressively. Near-total removal leads to good long-term control. Long-term follow-up with radiological studies is necessary as delayed recurrences can occur.