CHRONIC ENCAPSULATED INTRACEREBRAL HEMATOMA - CONTRIBUTION OF TL-201 SINGLE-PHOTON EMISSION COMPUTED-TOMOGRAPHY IN PREOPERATIVE DIAGNOSIS -CASE-REPORT

OBJECTIVE AND IMPORTANCE: Chronic encapsulated intracerebral hematoma is a fairly rare clinical entity. This unique lesion is peculiar for i ts clinical onset, formation of a capsule, and progressive enlargement . The mechanism for capsule formation and self-perpetuating expansion still remains uncertain, as well as the causal relationship with vascu lar malformations. Because of their pseudotumoral course and misleadin g neuroradiological features, these lesions can be misdiagnosed preope ratively as cerebral neoplasms. CLINICAL PRESENTATION: A 62-year-old m an was referred with a 2-month history of generalized tonicoclonic sei zures. There was no history of head injury or arterial hypertension. T he results of a neurological examination were normal. Computed tomogra phic scans revealed a slightly hyperdense roundish area in the right p arietotemporal region with ring-like enhancement after contrast medium injection, moderate mass effect, and perifocal low attenuation. With the provisional diagnosis of astrocytoma, the patient was admitted for a craniotomy. Before surgery, a thallium-201 single photon emission c omputed tomographic study was performed, which showed no abnormal upta ke of the tracer, raising significant doubt regarding the presumptive diagnosis of a tumor. INTERVENTION: Intraoperative findings revealed a hematoma, with a well-demarcated, thick, fibrous-elastic capsule. The re was evidence of repeated intracapsular hemorrhages. The lesion was totally removed, and the patient recovered fully. No other pathologica l findings, including vascular malformations, were noted. CONCLUSION: Chronic encapsulated intracerebral hematomas probably occur more frequ ently than the limited number of reported cases would indicate. This c ase represents a realistic clinical problem-solving setting in which t hallium-201 single photon emission computed tomography was used becaus e of its capacity for functional tumor detection and differential diag nosis.