Magnifying videoendoscopic findings of Peyer’s patches in the terminal ileum of Crohn’s disease

The macroscopic appearance of PPs was classified into two categories, a nodular or convolute elevation pattern (E type, fig 1A) and a flat pattern (F type, fig 1B), corresponding to lymphoid follicle and lymphocyte aggregation types, respectively, as described by Fujikura et al. 7 E-type PPs are associated with definite lymphoid follicles and abundant lymphoid hyperplasia, whereas F-type PPs consist of aggregated lymphocytes and reticulum cells, which were loosely mixed together. 7 Two endoscopic biopsy specimens taken from the domes of PPs were subjected to histopathological analysis and scanning electron microscopy. 3 All patients gave their written informed consent after approval by the university ethics committee. Taken together, the F-type PPs in Crohn's disease can reflect the irregularly affected domes with few covering villi. [...]the FAE of patients with active Crohn's disease is likely to be more exposed to the luminal antigens and to be in closer contact with the immune system. 4 Notably, the non-caseous epithelioid granuloma was frequently identified in the biopsy specimens taken from PPs.