Should Special Staining (AB/PAS) be Routinely Performed in Gastric Biopsies for the Detection of Intestinal Metaplasia?

Background. Gastric intestinal metaplasia increases the risk of gastric cancer by nine times. Although attempts are made to diagnose it using endoscopic methods, the final diagnosis is established by examining and reporting biopsy samples. Although there are studies in the literature that do not recommend routine special staining, many laboratories routinely perform alcian blue/periodic acid Schiffs (AB/PAS) staining, in addition to hematoxylin and eosin (H&E) staining. In this study, we examined the need for performing routine special staining. Methods. Seven hundred forty-one consecutive gastric biopsies obtained from the archive of our laboratory in 2019 were included in the study. One day after evaluating the cases using H&E, they were evaluated with AB/PAS without examining the H&E results. Result. All of the intestinal metaplasia lesions detected in H&E were observed with AB/PAS. However, we missed 14 (13.73%) of 102 intestinal metaplasia lesions with H&E that we detected using AB/PAS. We found the sensitivity and specificity of H&E in detecting intestinal metaplasia were 86.3% and 99.7%, respectively. When we retrospectively examined the 14 missed lesions in H&E staining, we could observe intestinal metaplasia in six biopsies, but it was not possible in eight (7.8%). Conclusion. Considering that gastric intestinal metaplasia is a precancerous lesion, we think that this ratio (13.73%) is high and that the number of malignancies can be reduced with a low-cost special stain. In this context, we advocate and recommend routinely performing inexpensive special staining such as AB/PAS to detect intestinal metaplasia in all gastric biopsies.

The immunohistochemistry and toluidine blue roles for Helicobacter pylori detection in patients with gastritis

BACKGROUND

Helicobacter pylori, which is associated with many upper gastrointestinal diseases, is found in half of the population of the world. Several special stains and immunohistochemistry stain for H. pylori are available. The need for and usefulness of immunohistochemical (IHC) technique has been debated for years. Toluidine blue is a simple stain for microbiological studies and is easily available in laboratories. Therefore, this study was conducted to compare hematoxylin and eosin (H&E), Giemsa and toluidine blue staining with immunehistochemistry for detection of H. pylori in patients with gastritis and also to correlate the results of these staining methods with pathological grading.

METHODS

We reviewed 54 consecutive gastric biopsy specimens stained by H&E and Giemsa as well as by toluidine blue and immunohistochemistry stains for H. pylori.

RESULTS

H. pylori was positively identified by IHC in 43 (79.63%) patients, while positive samples were found in 18 (33.33%), 24 (44.44%) and 33 (61.11%) patients using H&E, Giemsa and toluidine blue staining methods. Our results showed that classical histological staining methods are not sensitive enough to identify low numbers or coccoid forms of organism, while toluidine blue and immunohistochemistry play an important role in detection of H. pylori infection.

CONCLUSION

Toluidine blue has been proved to be much more reliable than H&E and Giemsa in detection of H. pylori. In addition, in post treatment biopsies and in biopsies with unexplained chronic active gastritis without histological evidence of H. pylori should have immunohistochemistry done to detect possible low density or coccoid form of organisms.

Helicobacter pylori: to stain or not to stain?

We performed a retrospective study to investigate the usefulness of immunohistochemical stains for the diagnosis of Helicobacter pylori (HP). We reviewed 200 consecutive gastric biopsy specimens, as well as immunohistochemical stains for HP. Of the biopsy specimens, 32 were positive for HP by immunohistochemical staining; of those, HP was seen on H&E stains in 29 cases (91%). The number of high-power fields required to detect HP on H&E-stained slides ranged from 1 to 25 (mean, 5.75). Combined significant (2+ or 3+) acute and chronic inflammation had a specificity of 98% and a negative predictive value of 97%. Our results show that, in our institution, HP can be seen relatively easily with H&E staining in the majority of cases; however, a small number of cases with significant inflammation can be missed if stains are not used.