Adenosquamous Carcinoma of the Stomach in a Caucasian Man: A Case Report

Abstract

Introduction: In all pathologic types of gastric cancer, adenocarcinoma is the most common, whereas the incidence of adenosquamous carcinoma (ASC) remains extremely low, accounting for less than 1% of total gastric malignancies. Due to the rarity of ASC, limited data are available to conclude the histogenesis, clinicopathologic characteristics, optimal treatment strategies, and prognosis. This rare clinical entity exhibits a higher prevalence in men, particularly in Asians, and typically manifests at advanced stages. Case report: In this report, we describe the case of an 88-year-old Caucasian man, an ex-smoker with chronic alcohol abuse and high-grade urothelial carcinoma, who developed upper gastrointestinal bleeding and anemia in December 2021. Upper gastrointestinal endoscopy revealed an ulcer-vegetative lesion next to the pylorus, confirmed pathologically as gastric carcinoma. A staging thoracic-abdominopelvic computed tomography scan excluded distant metastatic disease or other suspicious lesions. In February 2022, he underwent a sub-total distal gastrectomy with a Billroth type-2 anastomosis without complications. In the postoperative period, he developed pneumonia from which he recovered with antibiotics. The pathological examination identified an ulcer-infiltrative lesion in the antrum, infiltrating the gastric wall to the serosal layer, classifying it as a gastric adenosquamous carcinoma (pT4aN0R0). Conclusion: ASC represents a rare histological type of gastric carcinoma, especially in Western populations. The etiopathogenesis of this tumor remains incompletely understood and has a poor prognosis because presents at advanced staging and with frequent venous and lymphatic invasion. So, clinicians should be aware of this type of gastric carcinoma so as not to delay diagnosis and treatment, reducing survival.