Signet-ring cell carcinoma in gastric biopsies: expecting the unexpected.

AIMS: This study was designed to establish the relative prevalence of intestinal-type and signet-ring carcinoma in gastric biopsy specimens from ambulatory patients, to determine the percentage of signet-ring carcinomas that could be expected based on the available clinical and endoscopic information, and to estimate the likelihood of missing a tumour. METHODS: We extracted data of all patients with a diagnosis of primary gastric carcinoma from a national pathology database. We then reviewed clinical information and original slides, classified tumours as intestinal or signet-ring-type, and categorised the latter as 'unexpected' (no alarming symptoms, no mention of suspicious lesions) or 'expected' (clinical or endoscopic information suggestive of tumour). Unexpected signet-ring carcinomas were categorised as 'obvious' or 'challenging' (rare signet-ring cells; immunohistochemical stains used to confirm the nature of the infiltrates). RESULTS: There were 310 109 patients with gastric biopsies; 615 patients had primary gastric carcinoma (359 intestinal and 256 signet-ring-type). Gastric cancer was more common in men (OR 2.54; 95% CI 2.05 to 3.14; p<.0001) for intestinal-type and (OR 1.90; 95% CI 1.48 to 2.42; p<0.0001) for signet-ring cell type). Intestinal-type carcinoma occurred in older patients than signet-ring-type (median age 74 vs 65 years, p<0.001). There were 196 expected and 60 unexpected signet-ring carcinomas; 47 of the 60 unexpected cases were histopathologically obvious. Thus, only 13 signet-ring carcinomas (1 in 25 000 gastric biopsy sets) were truly unexpected. CONCLUSIONS: Signet-ring carcinoma is a rare finding in gastric biopsy specimens from ambulatory patients; routine due diligence and the clinical/endoscopic information provided are usually adequate to raise pathologists' index of suspicion.

Helicobacter pylori-negative gastritis: seek, yet ye shall not always find.

Since its recognition as the causative agent for most cases of gastritis, the prevalence of Helicobacter pylori-induced gastritis has been declining, in part due to the deliberate and inadvertent use of various medications. As a result, pathologists find themselves facing cases of gastritis in which, based upon history and histology, there are expected but undetectable H. pylori organisms. This review explores the 2 possibilities of false-negative and true-negative gastritides, including when and how to search for H. pylori, explanations for absent organisms in cases of true H. pylori gastritis, and other causes of gastritis that may mimic H. pylori infection. The latter group includes reactive gastropathy with focal activity, focally active gastritis and carditis, autoimmune gastritis, granulomatous gastritis, lymphocytic gastritis, and other infections.