There are a number of differences between the microscopic findings of primary gastrointestinal Crohn disease and that of MCD.
The histopathologic features of MCD compared to Crohn disease directly involving the skin (ie, perianal, peristomal, perifistular) are similar overall, with anatomic location being the main differentiating feature.
It has been suggested that antigens or immune complexes stemming from the gastrointestinal tract in primary Crohn disease travel through the circulatory system and deposit in the skin, creating perivascular granulomatous features seen on microscopic examination of MCD lesions.
20) Erythema nodosum is one of the most common cutaneous manifestations of Crohn disease and presents microscopically with granulomatous inflammation involving the septae of the subcutis (ie, septal panniculitis) with a mixed inflammatory infiltrate including neutrophils in the acute phase.
The odds ratios per allele for Crohn disease were 2.
The odds ratios per allele for Crohn disease were similar for the following subgroup comparisons: northern vs southern Europeans, adults vs children, and familial vs sporadic cases (Fig.
For Arg702Trp, the odds ratio for Crohn disease was 2.
Combining all 3 genetic variants, we obtained odds ratio for Crohn disease of 2.
Additional features of Crohn disease, such as fissuring ulcers, granulomas, lymphoid aggregates, and pseudopyloric metaplasia, were also noted in most of the cases.
Obliterative muscularization of the submucosa resembles the neuromuscular and vascular hamartoma, considered by Shepherd and Jass (5) as part of the histologic spectrum of Crohn disease.
Intestinal obstruction is an important feature in the natural history of Crohn disease.