A Rare Variant of Gastric Adenocarcinoma Presenting as a Symptomatic Early-Stage Submucosal Tumor in the Gastric Antral Primary.

Gastric adenocarcinomas are a well-known malignancy, with the vast majority presenting as primary mucosal invasions. However, a rare form of this cancer presents from the submucosal layer and mimics submucosal tumors (SMTs). This variant of gastric adenocarcinoma is not only rare, but it is also frequently misdiagnosed as other conditions such as gastrointestinal stromal tumors, lymphoma, or sarcoma. This case report describes a unique case of early gastric adenocarcinoma that presented as a submucosal tumor without invasion into the muscularis propria or primary involvement from the gastric mucosa. Additionally, this raises an important clinical question of whether this variant of gastric adenocarcinoma behaves differently from mucosal-origin cancers in terms of invasion and metastasis. This case highlights the diagnostic challenges and the importance of early detection and accurate diagnosis of this rare presentation of gastric adenocarcinoma. This case also provides valuable insights into the clinical variability of submucosal gastric adenocarcinomas and the need for further research to optimize its management and improve patient outcomes.