Atraumatic Shoulder Dislocation Revealing a Brain Tumor: A Case Report.

Non-traumatic shoulder dislocation may occasionally result from seizure-related disorders, and, in rare cases, from underlying brain tumors. We report a 23-year-old man who presented with anterior shoulder dislocation without apparent trauma. Computed tomography revealed a large Hill-Sachs lesion, a bony Bankart lesion, and a coracoid process fracture - findings inconsistent with a low-energy mechanism of injury. Because the injury occurred during sleep, an epileptic seizure was suspected. Further neurological evaluation identified focal epilepsy originating from the right frontoparietal region, and brain magnetic resonance imaging revealed a tumor in the right frontal lobe. Surgical resection confirmed an isocitrate dehydrogenase-mutant, Central Nervous System World Health Organization grade 2 astrocytoma. Following tumor resection and antiseizure therapy, the patient remained seizure-free while continuing conservative management for shoulder instability. Both the bony Bankart lesion and the coracoid process fracture had achieved bony union, the American Shoulder and Elbow Surgeons score reached 100, and functional recovery was excellent. This case highlights the importance of considering seizure-related or intracranial pathology in atraumatic shoulder dislocation and underscores the pivotal role of orthopedic surgeons in the early recognition of underlying central nervous system disease.