Diagnosis: Thrombosed AVM or a cavernous hemangioma
I don't know if this is a thrombosed AVM or a cavernous hemangioma. Both may hemorrhage or thrombose and be indistinguishable. AVMs are masses of arteries and veins and transitional "arteriolized veins". They may be located in the brain parenchyma (pial), dural, and mixed pial-dural. Patients may present with seizures, progressive neurologic deficit or subarachnoid hemorrhage. 90% are supratentorial, most commonly in the parietal region. Most pial AVMs present between 20 and 40 years of age. Multiple AVMs are associated with Osler-Weber-Rendu and Wyburn-Mason syndromes. Large vascular channels may be seen on CT perhaps with evidence of recent or old hemorrhage and calcification. No enhancement is present if the AVM has thrombosed. Cavernous hemangiomas are dilated vascular channels lined by endothelium with no normal intervening neural tissue. Clinically they may be asymptomatic or cause sensorimotor symptoms. They may have variable enhancement and signal characteristics depending on the age of the blood products. Cavernous hemangiomas may be familial and multiple in both the brain and spinal cord. Angiography was negative in this patient. Related Cases
