Non-specific presentation of metastatic small bowel adenocarcinoma with diagnostic challenges

Diagnosing small bowel adenocarcinomas presents challenges due to non-specific symptoms, rarity and gastroscopy and colonoscopy's limited small intestine access, highlighting targeted diagnostic procedures' necessity. We present a late-diagnosed metastatic small bowel adenocarcinoma case in a man in his 80s who had asymptomatic mild iron-deficiency anaemia 1 year before diagnosis, with no active bleeding found on endoscopies. He experienced a single rectal bleeding episode 9 months prediagnosis, with subsequent severe iron-deficiency anaemia and no clear gastrointestinal source identified on gastroscopy. For 2 months, he had intermittent postprandial diarrhoea without abdominal pain, infectious or inflammatory causes. He experienced significant weight loss over 3 months prediagnosis. Subsequent gastroscopy indicated duodenal-gastric food retropulsion, suggesting a downstream blockage. Magnetic resonance enterography showed proximal jejunum thickening. Push enteroscopy confirmed jejunum adenocarcinoma. CT scans detected liver and peritoneal metastases. After one chemotherapy cycle, his condition worsened, leading to his passing 2 months post diagnosis.