Abstract: Objective To clarify the clinical, pathological and endoscopic features of primary intestinal T-cell lymphomas (PITL), and to raise understanding and diagnostic levels of this disease. Methods Clinical data of 25 hospitalized patients diagnosed with PITL in Peking Union Medical College Hospital between Aug. 2012 and Aug. 2018 were retrospectively analyzed. Results In the 25 patients, 9 with monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), 5 with extranodal NK-/T-cell lymphoma (ENKTL), 5 with intestinal T-cell lymphoma-not otherwise specified (ITL-NOS), 4 with peripheral T-cell lymphoma (PTL), 1 with anaplastic large cell lymphomas and 1 with T-cell lymphoblastic lymphoma. The male-to-female ratio was 4:1, with the median age of 45 years (range, 13 to 82y) and the median disease duration of 5 months. The common clinical manifestations included weight loss (72%), abdominal pain (64%), diarrhea (64%) and fever (64%). Endoscopic features of 22 patients included 13 (59.1%) with ulcerative features, 7 (31.8%) with infiltrative features, and 2 (9.1%) with protrusive features. Twelve out of 22 patients (54.5%) were diagnosed by endoscopic biopsies, and only 7 (31.8%) were diagnosed at the first biopsy. Altogether 17 operations were performed, including 11 emergent operations due to complications (perforation and/or bleeding). Significant differences were found between MEITL and other subtypes in age of onset, weight loss, LDH level, EBV infection, hsCRP, site of involvement, diagnostic rate by endoscopic biopsy and endoscopic features. Conclusions Ulcerative and infiltrative features are common endoscopic findings of PITL. Since diagnostic rate by the first biopsy is low, more biopsies are needed in suspected patients to make diagnosis. The clinical characteristics of MEITL are different from other subtypes.

Key words: primary intestinal T-cell lymphoma, pathological subtype, endoscopic feature, clinical characteristics