A study on diagnosis and classification of gastrointestinal lymphoma based on histopathology and immunohistochemistry

Abstract

Background: WHO 2019 classification makes important histopathology additions to gastrointestinal lymphoma. This study aimed to investigate the role of histopathology and immunohistochemistry in the diagnosis and classification of gastrointestinal lymphomas. Materials and method: We investigated 141 patients from three tertiary referral hospitals with primary malignant lymphoma of the gastrointestinal tract. The lesions were evaluated and analyzed by using histopathology to classify the prevalent histopathological patterns of gastrointestinal lymphoma according to the WHO 2019 classification based on histopathology and immunohistochemistry. Results: 90.8% of gastrointestinal lymphomas were lymphoid infiltrates on histopathology. The most common type was diffuse large B-cell lymphoma (DLBCL) in which activated -B cell (ABC) subtype accounted for 54%, and germinal-center B-cell (GCB) accounted for 46%. In the second place was mucosa-associated lymphoid tissue (MALT lymphoma) accounting for 24%, followed by follicular lymphoma at 10.6%. Histopathology can orient to the diagnosis of DLBCL and MALT with sensitivity at 31% and 29%, respectively. Conclusions: Orientation based on histopathology of those tumor classifications is challenging. However, the combination of histopathology and immunohistochemistry could help to classify the majority of gastrointestinal lymphoma types. Key words: Gastrointestinal lymphomas, DLBCL, MALT.