Lymph folliculitis in ulcerative colitis.

Preferential involvement of the appendix has recently been confirmed in ulcerative colitis. Since the appendix is an aggregate of lymph follicles, this new observation implies a critical role of the lymph follicles, of both the large bowel and the appendix, in an etiopathogenesis of ulcerative colitis. This report presents two cases of ulcerative colitis in which lymph folliculitis and lymphoid hyperplasia were observed. Lymph folliculitis was observed endoscopically in a border between an established lesion and an uninvolved area. Case 1, proctitis type, relapsing remitting, mild in severity, showed lymph folliculitis in a proximal border of an established rectal lesion. Case 2, with left-sided colitis, mild in severity, had a skip appendiceal orifice inflammation. Lymph folliculitis was observed in the cecum surrounding established appendiceal orifice inflammation. In both cases, lymphoid hyperplasia was observed in an uninvolved area with clear vascular patterns. These two cases clearly demonstrate the involvement of gut lymph follicles in ulcerative colitis. Lymph folliculitis and/or lymphoid hyperplasia was proposed to be early lesions in ulcerative colitis. In addition, the need for microbiology targeting lymph follicles of the large bowel and appendix is stressed in order to disclose the casual microbial agents in ulcerative colitis.