Thoracic Intradural Extramedullary Cavernous Malformation Mimicking Meningioma.

Cavernous malformation, also known as cavernoma or cavernous hemangioma, is a benign vascular malformation characterized by abnormal proliferation of capillaries that lack intervening neural tissue. Spinal intradural extramedullary cavernous malformations are exceedingly rare and, therefore, are often misdiagnosed. Here, we report a rare case of thoracic intradural extramedullary cavernous malformation that mimicked meningioma on preoperative imaging. A 77-year-old male patient presented with a two-month history of myelopathy, progressive paresthesia in the lower extremities, and difficulty walking, noted during an outpatient clinic visit. Spinal magnetic resonance imaging detected an intradural extramedullary mass lesion on the dorsal side at the Thoracic (Th) 10 vertebral level, compressing the thoracic cord. Preoperative imaging revealed a uniform T1- and T2-weighted intensity signal, suggesting meningioma. Intraoperatively, the mass appeared reddish with multiple abnormal vessels and adhered firmly to the thoracic cord. The lesion was completely resected, and postoperative pathological examination confirmed the diagnosis of cavernous malformation. The patient's preoperative symptoms improved postoperatively. Thoracic intradural extramedullary cavernous malformations are extremely rare and typically present with heterogeneous intensity signals on magnetic resonance imaging. Additionally, they can cause subarachnoid hemorrhage, emphasizing the importance of considering them in the preoperative differential diagnosis, even though imaging characteristics may be atypical. Surgical gross total resection should be considered to prevent future hemorrhage and neurological deterioration.