Autoimmune gastritis (AIG) is chronic atrophic gastritis caused by an autoimmune mechanism of unknown etiology and presents with various pathological conditions by causing an achlorhydria state through parietal cell damage. The most characteristic endoscopic finding in AIG is advanced corpus-dominant mucosal atrophy. A recent study that examined several cases in Japan revealed the presence of endoscopic features other than corpus-dominant advanced atrophy. Remnants of oxyntic mucosa and sticky adherent dense mucus were found in ≥30% of cases, and hyperplastic polyps were found in ≥20% of cases. In image-enhanced endoscopy (IEE), white globe appearance (WGA) was observed in 32% of AIG cases. Additionally, some reports have stated that the findings in AIG cases using IEE showed cast-off skin appearance (CSA) and foveola type mucosa; however, a consensus is yet to be achieved. These endoscopic results were found in cases of advanced-stage AIG. There have been few reports concerning early-stage AIG cases. In these few reports, all of the cases were pathologically diagnosed as early AIG. In all of the cases, the pathological findings almost always showed neither parietal cell destruction nor atrophy. Endoscopic findings such as “mosaic pattern with slight swelling of the areae gastricae”, “diffuse reddened and edematous gastric fundic gland mucosa”, and “pseudopolyp-like nodules” may be common characteristics of early images. In such early cases, high antibody titers, no atrophic changes, and few clinical abnormal findings were shown. Endoscopists are expected to update their knowledge regarding AIG diagnosis with the evolution of imaging equipment.

Differentiated gastric cancer generally develops in the atrophic gastric mucosa, although undifferentiated cancer is sometimes encountered in patients with severe atrophic gastritis. We characterized the endoscopic features of undifferentiated gastric cancer in patients with severe atrophic gastritis. Stage IA early gastric cancer was diagnosed in 501 patients who were admitted to our hospital between April 2003 and March 2012. The endoscopic and pathological findings were compared among 29 patients with undifferentiated cancer and severe atrophic gastritis, 104 patients with undifferentiated cancer and mild/moderate atrophic gastritis and 223 patients with well-differentiated cancer and severe atrophic gastritis. Endoscopic atrophic gastritis was classified according to the Kimura-Takemoto classification as no gastritis, C-1 and C-2 (mild), C-3 and O-1 (moderate) or O-2 and O-3 (severe). The tumors were larger and showed deeper mural invasion in the patients with undifferentiated cancer and severe atrophic gastritis than in those with well-differentiated cancer and severe gastritis or undifferentiated cancer and mild/moderate gastritis. On endoscopy, undifferentiated cancer associated with severe gastritis was often red in color. It is often difficult to diagnose early undifferentiated gastric cancer, especially in patients with severe atrophic gastritis. The present study characterized the important endoscopic features of such tumors.

Objective The incidence of osteoporosis is increasing with the rapid aging of the Japanese population. Bisphosphonates are first-line agents used for the treatment of osteoporosis, but they can cause upper gastrointestinal mucosal injury. This study investigated symptoms and upper gastrointestinal mucosal injury associated with oral bisphosphonates. Methods Symptoms were evaluated using the F-scale questionnaire, and esophageal mucosal injury and gastroduodenal ulceration were assessed by endoscopy. Patients were stratified by the type of bisphosphonate (alendronate, risedronate, or minodronate), treatment schedule (once weekly or every four weeks), and the concomitant use of other medications [antithrombotic agents, nonsteroidal anti-inflammatory drugs (NSAIDs), or acid suppressants]. Patients The subjects included 221 patients treated with oral bisphosphonates for at least one month. Results The median F-scale total score was 4 (0-34), reflux score was 2 (0-20), and the mean dyspepsia score was 2 (0-16). Endoscopy showed esophageal mucosal injury of Grade A or worse (Los Angeles classification) in 22/221 patients (10.0%) and gastroduodenal ulcers in 9 patients (4.1%). The dyspepsia score in patients who took minodronate every four weeks was significantly lower (p<0.05) in comparison to patients who took other bisphosphonates. The dyspepsia score was significantly higher (p<0.05) and mucosal injury was significantly more frequent in patients who also used antithrombotic agents and NSAIDs. Conclusion Symptoms and upper gastrointestinal mucosal damage were not necessarily frequent or severe in patients treated with bisphosphonates. However, the concomitant use of bisphosphonates with antithrombotic agents and NSAIDs increased both symptoms and mucosal injury. The symptoms were milder in patients using minodronate once monthly.

Significant atrophic gastritis in the fundic gland region is a well-known endoscopic finding observed in autoimmune gastritis (AIG). The endoscopic features of early AIG have not been reported. Iron deficiency, vitamin B₁₂ deficiency, anemia, or neurological symptoms may not be observed in the early stages of AIG, and it may thus be difficult to diagnose early AIG based on clinical findings. We treated a 50-year-old Japanese female whose condition was suspected to be early AIG. The endoscopic findings showed normal gastric pyloric gland mucosa, and diffuse reddened and edematous gastric fundic gland mucosa. Pathologically, local infiltration of lymphocytes and decrease of parietal cells was present in a deep part of the gastric fundic gland mucosa. Blood tests showed that the titer of parietal cell antibody (PCA) was 1:320 and the gastrin level was 820 pg/ml. We determined that the patient had AIG because she also had Hashimoto’s disease, the PCA titer was high, the serum gastrin level was slightly increased, and inflammation was observed only in the gastric body on the endoscopic images. To the best of our knowledge, this is the first case report of endoscopic findings that suggest early AIG, before atrophic changes were observed.

Artificial-intelligence-based computer-aided diagnosis (CAD) systems have developed remarkably in recent years. These systems can help increase the adenoma detection rate (ADR), an important quality indicator in colonoscopies. While there have been many still-image-based studies on the usefulness of CAD, few have reported on its usefulness using actual clinical videos. However, no studies have compared the CAD group and control groups using the exact same case videos. This study aimed to determine whether CAD or endoscopists were superior in identifying colorectal neoplastic lesions in videos. In this study, we examined 34 lesions from 21 cases. CAD performed better than four of the six endoscopists (three experts and three beginners), including all the beginners. The time to lesion detection with beginners and experts was 2.147 ± 1.118 s and 1.394 ± 0.805 s, respectively, with significant differences between beginners and experts (p < 0.001) and between beginners and CAD (both p < 0.001). The time to lesion detection was significantly shorter for experts and CAD than for beginners. No significant difference was found between experts and CAD (p = 1.000). CAD could be useful as a diagnostic support tool for beginners to bridge the experience gap with experts.

Although gastric mucosa-associated lymphoid tissue (MALT) lymphoma without Helicobacter pylori (HP) has increased recently, a specific endoscopic classification has not been established; its endoscopic characteristics have not been investigated. In this study, we retrospectively investigated gastric MALT lymphoma without HP in our hospital and assessed differences in the endoscopic findings according to HP infection status. Fifty-seven patients with gastric MALT lymphoma Lugano stage I, diagnosed between January 2013 and March 2023, were divided into three groups (currently HP infected, previously infected, and uninfected), wherein their endoscopic findings were evaluated. Furthermore, the superficial type, as per the classification of Sano et al., was independently subdivided based on the endoscopic differential diagnoses, as follows: atrophic gastritis-like, angiodysplasia-like, superficial gastritis-like, and undifferentiated carcinoma-like. Compared with the currently infected group, the HP-uninfected group tended to have more small lesions without erosion and more discolored, undifferentiated carcinoma-like depressed lesions. In addition, the positive rate of the tree-like appearance (TLA) and ballooning characteristics of gastric MALT lymphoma in magnified findings was lower in the HP-uninfected group. In patients without HP infection, MALT lymphoma should be excluded, even in the absence of suspicious magnifying findings such as TLA or ballooning.