Marked thickening of muscularis mucosae and submucosa in the gastric cardia: A histopathological study of 110 surgical resection cases

Objective To investigate histopathologic changes of muscularis mucosae (MM) and submucosa in the gastric cardia. Methods We performed a histopathology study of 50 distal esophagectomies with proximal gastrectomies for esophageal squamous cell carcinoma as the study (non‐cancerous cardiac) group and 60 gastrectomies for early gastric cardiac carcinoma as the cancer group. The gastroesophageal junction was defined as the distal end of squamous epithelium, multilayered epithelium, or deep esophageal glands or ducts. Gastric cardia (n = 110) was defined as the presence of cardiac and cardio‐oxyntic mucosae distal to the gastroesophageal junction. Results The average thickness of MM and submucosa in the cardia was 1.04 and 1.41 mm, respectively, which was significantly thicker than that in distal stomach (n = 34) (0.22 and 0.99 mm) or distal esophagus (n = 92) (0.60 and 1.15 mm). In the cardia, thickened MM displayed frayed muscle fibers (93.3%) with a significantly higher prevalence of entrapped glands, cysts, and lymphoid follicles than in the distal stomach or distal esophagus. In the submucosa fatty changes, cysts, and abnormal arteries were significantly more common in the cardia than in the distal stomach or distal esophagus. Compared with the study group, the cardia in the cancer group showed significantly thicker MM (average 1.31 vs 0.72 mm) and submucosa (average 1.61 vs 1.16 mm), more frequent frayed MM (93.3% vs 60.0%), prolapse‐like changes (50.0% vs 2.0%), and cysts (26.7% vs 4.0%). Conclusion MM and submucosa of the cardia were significantly thickened, especially in early gastric cardiac carcinomas.