Clinicopathological characteristics of thymic hyperplasia with lymphoepithelial sialadenitis-like features

Abstract

Objective To understand and summarize the clinicopathological characteristics and differential diagnosis of lymphoepithelial sialadenitis (LESA)-like thymic hyperplasia. Methods The clinicopathological data of patients with LESA-like thymic hyperplasia diagnosed in our hospital from October 1, 2019 to September 1, 2023 were collected, and the related literatures on their epidemiological characteristics, clinicopathological features, treatments and prognosis were reviewed. Results There were 2 female patients with LESA-like thymic hyperplasia included, at an onset age of 51 and 52 years, respectively. Imaging examination revealed an anterior mediastinal mass in both patients, with the largest diameter of 7.5 and 12.0 cm, respectively. Microscopic morphology and immunophenotype analysis showed there were florid lymphoid follicles with germinal centers. Reticular or nested thymic epithelial, thymic corpuscles and lymphoepithelial lesions without dysplasia were seen in the interfollicular areas as well. Focal cystic changes, cholesterol crystals and the formation of cholesterol granuloma were observed. Our results were similar to the pathological morphology and immunohistochemical phenotype of 46 cases with LESA-like thymic hyperplasia reported in the literature. They had favorable prognosis, except 5 patients progressed to lymphoma. Conclusion LESA-like thymic hyperplasia is a benign disease with unique morphological characteristics and of favorable prognosis. But rare patients can progress to lymphoma, therefore regular and close follow-up is still required.

Keywords

• thymic hyperplasia
• thymic hyperplasia with lymphoepithelial sialadenitis-like features
• lymphoid follicles
• thymic epithelium
• lymphoma