Rectal tonsil:Clinicopathological features of 3 cases and literature review
Objective:Rectal tonsil(RT)is a benign lesion characterized by reactive hyperplasia of lymphoid tissue within the rectum.It is clinically rare and easily misdiagnosed.This article aims to improve the understanding of RT by discussing its clinicopathological features,differentiation,and diagnosis.Methods:Clinicopathologic features and immunophenotype results of 3 patients diagnosed with RT were analyzed retrospectively,and relevant literature was reviewed.Results:All three RT patients were male,aged 6 to 71 years,presenting with clinical symptoms such as constipation,hematochezia,or anal protruding masses.Colonoscopy showed polyp-like elevations.Low-power microscopy showed lymphocyte and plasma cell infiltration in the mucosal and submucosal layers,forming variably sized and shaped lymphoid follicle structures.High-power microscopy did not reveal significant cellular atypia,although mitotic figures were observed in some areas.Immunohistochemically,T-cell markers(CD3,CD5)and B-cell markers(CD20)were expressed,with germinal centers expressing CD10 and B-cell lymphoma(Bcl)-6,but not Bcl-2.CD21 outlined a complete follicular dendritic cell(FDC)network.All three cases tested negative for Epstein-Barr virus encoded RNAs(EREB).The patients underwent polyp resection,with no recurrence or metastasis observed during the follow-up period of 4 to 20 months.Conclusion:RT is a relatively rare and not widely recognized disease of unknown etiology.Understanding its clinicopathological features is crucial,and diagnosis relies on pathological examination.