RARE-22. CHALLENGES IN MANAGEMENT OF CNS INVOLVEMENT OF CUTANEOUS T-CELL LYMPHOMA

Abstract

Abstract BACKGROUND Cutaneous T-cell lymphoma (CTCL) is a group of T-cell lymphomas occurring primarily in the skin, without evidence of disease elsewhere. Central nervous system (CNS) involvement of CTCL is extremely rare, with a reported incidence of 5–9%. Due to its infrequency and radiographic appearance which mimics other CNS processes, CNS CTCL may be misdiagnosed. Here, we describe 8 cases of CNS CTCL at a single institution. METHODS The electronic medical records at our institution were queried for cases of CNS involvement by CTCL, between 2004–19. Clinical data, imaging and surgical pathology were reviewed. RESULTS Eight patients were diagnosed with CNS CTCL with median age of 68 and median time to development of CNS disease of 17 months. 1 patient had synchronous presentation of cutaneous and CNS disease identified at autopsy. Seven out of eight patients presented neurologically with behavioral and mental status changes and 1 patient had concurrent intraocular disease. Imaging showed bilateral non-enhancing T2/FLAIR signal changes in three patients; multifocal enhancement was noted in the others. Malignancy, inflammatory processes and infections including progressive multifocal leukoencephalopathy (PML) were often included in the radiographic differential diagnosis. Prior systemic therapies were variable, including palliative radiation, phototherapy, myeloablative chemotherapy followed by allogeneic stem cell transplant and oral methotrexate. 5 of 8 patients had active cutaneous disease at the time of CNS relapse. Six patients received initial treatment for CNS disease with high-dose methotrexate (HD-MTX). Comprehensive genomic analysis revealed recurrent alterations in genes associated with regulatory T-cell differentiation (SOCS1, NOTCH1), tumor suppressors (CDKN2A, PTEN, TP53); one case was hypermutated. CONCLUSIONS CNS involvement of CTCL is rare, occurring more than a year after initial cutaneous disease. Clinical and radiographic findings may be variable, necessitating high clinical suspicion. Most patients respond to HD-MTX. Further molecular analysis is ongoing.