Lymph node pathology in Henoch-Schönlein purpura.

This report describes two cases of Henoch-Schönlein purpura with unusual lymph node pathology. The patients presented with severe colicky abdominal pain mimicking acute appendicitis but a normal appendix was removed in each case. Enlarged mesenteric lymph nodes were removed, with a clinical suspicion of Yersinia infection. Cultures and serology were negative. Histological examination of the lymph nodes revealed follicular granulomas, follicular microabscesses and leucocytoclastic vasculitis. Immunohistochemical studies revealed deposition of IgA, IgG and C3 in the vessel walls, the finding of IgA supporting a diagnosis of Henoch-Schönlein purpura.