Authors: Julie Tuypens , Jaro Van Zande , Yves Van Molhem , Koenraad Hendrickx

Abstract

Background: Gastric cancer (GC) is the fifth most common diagnosed cancer and the third most prevalent cause of cancer-related mortality globally. Although there has been a decline in the overall occurrence of gastric cancer over recent years, the prevalence of signet-ring cell carcinoma (SRCC) has shown a consistent rise, representing up to 30% of gastric adenocarcinoma cases.
Case Presentation: We present an unusual case of a 22-year-old woman with gastric outlet syndrome secondary to a primary gastric signet-ring cell carcinoma. A gastro-duodenal endoscopy showed a markedly oedematous substenotic pyloro-bulbar region without any ulcers. Biopsy demonstrated gastric mucosa with tumoral cells originating from an adenocarcinoma of the diffuse type (signet-ring cell carcinoma). An abdominal CT scan detected an intestinal malrotation, making an endoscopic gastro-enterostomy not feasible. Despite FDG PET-CT showed no distant metastasis, during staging laparoscopy metastatic implants were detected on the peritoneum, diaphragm and small bowel mesentery. There was no amplification of the HER2 gene and no PD-L1 expression in the tumour cells, making this patient not eligible for immunotherapy. A jejunostomy was placed for enteral nutrition and chemotherapy (FOLFOX) was initiated.
Conclusion: Although diffuse type gastric carcinoma in young adults is extremely rare, clinicians should be aware of its growing incidence and the importance of early diagnosis. This case advocates for considering gastric carcinoma in the differential diagnosis of gastric outlet syndrome, even in a patient population where this rarely occurs, as early-stage diagnosis is crucial to afford these patients improved opportunities for curative treatment.

Keywords: Case report, Gastric adenocarcinoma, Signet-ring cell carcinoma, Diffuse gastric cancer, Gastric outlet syndrome.