case_images: PMC10844135_01
case_images: Computed tomography angiogram of the abdomen and pelvis showed large-volume pneumoperitoneum and ascites (arrow), suggestive of perforated viscus and peritonitis
case_images: cureus-0016-00000051767-i01.jpg
case_images: PMC10844135_01_cureus-0016-00000051767-i01.jpg
case_images: FIG1
case_images: CT angiogram of the abdomen and pelvis showed large-volume pneumoperitoneum and ascites, concerning perforated viscus and peritonitis secondary to gastric perforation (Figure 1). CT angiogram of the chest showed no metastasis.
case_images: Histology of gastric ulcer biopsy. a) Hematoxylin and eosin (H&E) of the gastric ulcer biopsy showing poorly differentiated adenocarcinoma. b) H&E of the peritoneal implant biopsy showing poorly differentiated adenocarcinoma. c) H&E of the omental biopsy showing poorly differentiated adenocarcinoma. Immunohistochemistry (IHC) showing CK7/CK20/CDX2 positive and MUC2/MKX3.1 negative. d) H&E of the peritoneum, mesenteric small bowel biopsy, and positive for poorly differentiated adenocarcinoma. e) H&E of the mesocolon soft tissue biopsy positive for poorly differentiated adenocarcinoma. All biopsies had histomorphology and immunostains supportive of metastatic adenocarcinoma of gastric origin.
case_images: cureus-0016-00000051767-i02.jpg
case_images: PMC10844135_01_cureus-0016-00000051767-i02.jpg
case_images: FIG2
case_images: Taken together, the adenocarcinoma was likely of gastric origin and staged as TxNxM1 stage IV gastric adenocarcinoma (Figure 2).