Monomorphic epithelial intestinal T-cell lymphoma: a clinicopathological characteristic analysis / 白血病·淋巴瘤

ABSTRACT

Objective:To investigate the histopathological morphology, immunophenotype, molecular pathological features, clinical prognosis and treatment of monomorphic epithelial intestinal T-cell lymphoma (MEITL).Methods:The clinicopathological data of 5 patients with MEITL in Sichuan Jinyu Medical Laboratory Center Co., Ltd from March 2019 to February 2021 were retrospectively analyzed, and literatures were reviewed. All cases were tested by using histopathology, immunohistochemistry, in situ hybridization of Epstein-Barr virus (EBV) and T-cell clonability assessment, and 1 case had second-generation sequencing (NGS) test. Clinical follow-up was performed in 2 patients.Results:All 5 MEITL cases were middle-aged and old men. The histopathology showed that intestinal wall was diffuse with tumor cells infiltrating, and the cells were obviously epitheliophilic. All the tumor cells CD3, CD8, CD56, GrB were positively expressed, and expressions of other T-cell markers were different, among which 1 case had CD30 positive and 1 case had CD20 positive. All 5 cases were negative for EBV by in situ hybridization. Monoclonal rearrangement of T-cell receptor gene was detected in all 5 cases. Mutations of BCOR, JAK3, STAT5B and ATM were detected in 1 case by using NGS. Among 2 cases followed-up, 1 patient relapsed 7 months after he had the initial onset and underwent the first operation, and then he had another operation. This patient finally died of extensive metastasis in the lung, liver and abdominal cavity as well as ascites 13 months later; another patient died 1 month after emergency surgery for perforation.Conclusions:MEITL is a rare primary T-cell lymphoma of the digestive tract. The oncogenic event in the pathogenesis of MEITL mainly involves mutations in the tumor suppressor gene SETD2 and mutations in one or more genes of the JAK/STAT pathway. Currently, there is no standard treatment for MEITL. Most treatment options include surgical resection and anthracycline-based chemotherapy.