Pattern-based approach to duodenitis and duodenopathy.

Duodenum is currently the most popular site to obtain samples of intestinal mucosa for recognition of a disorder leading to malabsorption. Although there are significant overlaps between histological findings described in various non-neoplastic diseases of the duodenum, recognition of one of the six basic morphologic patterns, namely coeliac disease-like pattern, active chronic duodenitis, acute GvHD-like pattern, enteritis with predominant eosinophilic infiltration, enteritis with predominant infiltration by macrophages, and non-inflammatory enteropathy, usually allows diagnostic separation, especially if subtle histological details, clinical setting and serological investigation are taken into account.