Tumefactive MS lesions under fingolimod: a case report and literature review.

OBJECTIVE:To report about a possible association between fingolimod treatment and tumefactive demyelinating lesions (TDL) as seen in a patient developing repeated TDL on continued fingolimod therapy. METHODS:We performed serial clinical and radiologic assessments and immunophenotyping of blood and CSF immune cells. We also present a literature review about recent similar cases. RESULTS:Clinical course and radiologic findings were consistent with diagnosis of TDL. Immune cell phenotyping showed pronounced shifts in the immune cell composition related to fingolimod treatment. In addition, we observed a subset of highly differentiated effector cells (CD45R0negCCR7neg) within the CD8+ T-cell population, which was about 2-fold enriched in the CSF compared to the peripheral blood. CONCLUSION:Our observations add further evidence for the development of atypical demyelinating lesions in some patients receiving fingolimod. These might be related to a treatment-associated shift in the immunopathology of specifically susceptible individuals.