Primary anaplastic large cell lymphoma in the dura of the brain: case report and prediction of a favorable prognosis.

Anaplastic large cell lymphoma (ALCL) is a rare T-cell lymphoma composed of CD30-positive lymphoid cells. ALCL arising in the dura matter of the brain is even more infrequent, in which only one case has been reported worldwide so far. We report a case of a 30-year-old immunocompetent male with a dura-based mass, radiographically consistent with meningioma. However, the excised mass via a left parieto-occipital craniotomy was composed of large, pleomorphic lymphoid cells to be immunopositive for CD3, CD30, anaplastic lymphoma kinase protein-1 (ALK-1) and epithelial membrane antigen (EMA), and immunonegative for CD20, CD15 and CD68. Multiple ALK gene fusion signals in the ALK locus were detected by fluorescence in situ hybridization (FISH) analysis. The patient was treated with CHOP chemotherapy and intrathecal methotrexate along with brain radiation therapy, which resulted in a complete remission. In an analysis of 25 previously reported primary CNS ALCLs, ALK-1 positivity was shown to be prevalent in younger age, as ALCL occurs outside the brain. Patient less than 23 years, ALK-1 positivity and unifocal tumor may be associated with a better prognosis. However, sex, dural or leptomeningeal involvement, immune status, and tumor necrosis do not appear to have any influence on survival.