A Bleeding Mystery Unveiled: Metastatic Melanoma Hidden as Post- Polypectomy Anaemia

A 74-year-old patient appeared with a positive occult blood test. A colonoscopy is recommended, which reveals a sessile polyp measuring approximately 3 cm in the lower rectum (Paris Is, NICE III). The lesion is excised endoscopically, and the biopsies confirm the diagnosis of tubulovillous adenoma with low-grade dysplasia.

One month post-procedure, the patient presented to the emergency department with symptomatic severe normochromic, normocytic anaemia, exhibiting a haemoglobin level of 6 g/dL. He experienced minimal rectal bleeding. Post-polypectomy haemorrhage was suspected, prompting a colonoscopy that revealed a healed polypectomy site with scar tissue, but no evidence of current bleeding. A transfusion rectified his anaemia, and he was released.

Three weeks later, the patient presents to the emergency room with anaemia (4 g/dl). An upper gastrointestinal endoscopy was conducted, finding an irregularly sharp pigmented lesion in the duodenum. Biopsies of the lesion confirmed metastatic melanoma, a diagnosis subsequently corroborated by histology and immunohistochemistry.

Publication History

Article published online:
27 March 2025