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.