Multicenter retrospective analysis of the clinicopathologic features of monomorphic epitheliotropic intestinal T-cell lymphoma.

Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a provisional entity in the 2017 World Health Organization classifications. To further elucidate the clinicopathologic features of this new disease, we carried out a retrospective, multicenter analysis of 42 patients with MEITL. The median age of the patients was 59 years (range, 20-84 years), and 27 patients (64 %) were male. Thirty-two patients (76 %) were Ann-Arbor stages I-II and 28 (67 %) were Lugano stages I-II. The most frequent site of involvement was the jejunum (N = 21). Most cases expressed CD8 (79 %) and CD56 (95 %) and did not express CD30 (5 %) or EBER (0 %). The median progression-free survival was 6.9 months (95 % CI 4.3-9.6); the median OS was 14.8 months (2.4-27.2). Thirty-two patients (76 %) underwent surgery and 37 (88 %) received chemotherapy. A complete response (CR) rate was 38 %. Sixteen patients had undergone autologous stem cell transplantation (ASCT). Relapse or progression was documented in 24 cases, most frequently in the primary site (N = 23). Four cases showed central nervous system relapse. Age over 55 years, poor performance scale, advanced Lugano stage (II-IV), not achieving CR, and not receiving ASCT were associated with inferior OS. While the optimal management of MEITL remains undetermined, achieving CR and consolidative ASCT seem essential. As CHOP might be insufficient for achieving CR, more efficient combinations should be investigated. Additionally, considering the frequent local failure and CNS relapse, novel therapeutic approaches are required to improve survival.