Tuberculoma of the brain with unknown primary infection in an immunocompetent host

Abstract

Isolated cerebral tubercular abscess is uncommon in immunocompetent hosts. Our patient had a tuberculoma with no known primary and an atypical MRI appearance. We present a 67-year-old African-American male with complex partial seizures. A CT scan of the brain revealed a new right frontal mass which was not found on imaging two years prior. In view of the patient's age and absence of any known primary malignancy, a primary brain tumor was considered to be the likely diagnosis. On MRI, the mass did not display ring enhancement or necrosis. Rather, the mass was lobulated, with near-uniform enhancement of the lesion with a surrounding high fluid-attenuated inversion recovery signal predominantly in the right frontal region, which extended inferiorly to the parietal region. The lesion showed a few punctate foci of low signal intensity on gradient echo MRI sequences, suggestive of hemorrhage. The mode of infection is unknown. However, it is important to include tuberculosis as a differential diagnosis, especially if the lesion appears to be non-primary, if a primary neoplasm or other metastases are not identified on further investigation, and in a patient of African-American ethnicity. To our knowledge, this is the first record of an isolated tubercular abscess of the brain in a developed country.