Small bowel gastric metaplasia: a report of three cases in children

Anal-transitional and bronchial metaplasia within the ileostomy of a small bowel allograft: a case report

Epithelial metaplasia is a phenomenon where a native mucosal cell type is replaced by another due to altered stem cell differentiation, usually as the result of long-standing injury or inflammation. It is common in ileostomies performed with native small bowels for both neoplastic and inflammatory conditions. We present a case of anal-transitional and bronchial epithelial metaplasia that occurred near the ileostomy of a small bowel allograft in a seven-month-old male transplanted for short bowel syndrome related to gastroschisis. The anal-transitional metaplastic mucosa had an immunophenotype (CK7- and p63-positive) similar to that of normal mucosa at the anal transition zone and a DNA STR profile consistent with the donor. To our knowledge, this represents the first report of this type of metaplasia occurring in ileostomies in the English literature. It is important for clinicians and pathologists to recognize these benign mucosal alterations to avoid diagnostic confusion.

Endoscopic biopsy features and diagnostic challenges of adult Crohn's disease at initial presentation

AIMS

Endoscopic biopsy diagnosis of Crohn's disease (CD) is problematic due to lack of specific microscopic features and patchy involvement. There is no documentation of the pattern and severity of microscopic features of CD at initial presentation in adults or children. We aimed to assess the initial mucosal biopsy features of CD in adults and to identify any specific features to confirm the diagnosis.

METHODS

Thirty sets of initial, adult endoscopic biopsies suspected to be CD with subsequent resections, repeat biopsies with long-term follow-up, and/or other confirmatory laboratory results were analysed by three gastrointestinal pathologists, blinded for the final diagnosis for mucosal architectural changes, epithelial abnormalities, chronic and active inflammation and changes of muscularis mucosae and submucosa. There were 25 cases of CD and five cases of non-CD for comparison (3 tuberculosis and 2 right-sided diverticular disease and associated colitis). Cases confirmed as ulcerative colitis were excluded, as diagnostic challenges are already well established.

RESULTS

The majority of initial biopsies (96%) of CD were abnormal with active chronic ileocolitis with a very high proportion (80%) showing the classic combination of abnormal mucosal architecture, epithelial abnormalities and active chronic inflammation. The most sensitive feature was lamina proprial chronic inflammation (sensitivity 92.7%). Sensitivity for other features was as follows: active inflammation 87.8%, basal plasmacytosis 82.1%, architectural changes 80.5% and epithelial abnormalities 70.7%. Abnormalities were found in 94% of ileal and 76% of colonic biopsies. No feature was specific as all tuberculosis and diverticular disease cases showed the classic combination. Granulomata were seen in 10 of 41 CD, in all five tuberculosis and in no diverticular disease biopsies. Small, tight, well defined granulomata characterised CD over large coalesced ganulomata of tuberculosis. Paneth cell and pseudopyloric metaplasia was seen only in CD (2/25).

CONCLUSIONS

Initial endoscopic biopsies of adult CD are significantly abnormal and a majority shows active chronic ileocolitis. The features are sufficiently important to suspect CD at initial presentation in the appropriate clinical setting. Tuberculosis and diverticular disease associated colitis are two important mimics to consider in addition to ulcerative colitis.

Infection with human H1N1 influenza virus affects the expression of sialic acids of metaplastic mucous cells in the ferret airways

Glycans terminating in sialic acids serve as receptors for influenza viruses. In this study ferrets were infected with influenza virus A/New Caledonia/20/99, and the in situ localization of sialic acids linked alpha2-3 and alpha2-6 in the airways was investigated in infected and non-infected animals by use of sialic acid detecting lectins and a monoclonal antibody towards the Sialyl-Tn antigen. The goblet cells in the bronchi from non-infected ferrets expressed Sialyl alpha 2-6Gal glycans, while the seromucinous glands in the submucosa expressed Sialyl alpha 2-3Gal glycans. In the infected animals, the surface epithelial cells in some bronchi showed metaplasia and expressed the Sialyl-Tn antigen: Sialyl alpha 2-6GalNAc-O-Thr/Ser. The submucosal tracheal glands in these animals showed increased expression of both Sialyl alpha 2-3 and Sialyl alpha 2-6 epitopes.