The size and histological appearances of mesenteric lymph nodes in Crohn's disease.

The size of the related lymph nodes and their histology has been correlated in 34 specimens of Crohn's disease. Granulomata were shown not to affect the maximum diameter of the lymph nodes nor to be more frequent in large nodes. The enlargement of lymph nodes appeared to be due to simple, non-specific, reactive changes. Granulomatous lymph nodes were found in 38% of all our cases of Crohn's disease and in 63% of those cases with granulomata in the bowel wall. One case was found with granulomata in the lymph nodes which were not seen in the bowel wall. The mesenteric lymph nodes of 22 cases of ulcerative colitis were shown to be not significantly different in size from those of Crohn's disease. The diameter of the lymph nodes on the histological section was shown to underestimate the diameter of nodes in the fresh state by a factor of 1.5.