Gastrointestinal (GI) metastases from skin melanoma are rare and often diagnosed lately. Endoscopic identification of lesions in both upper and lower GI tracts is quite exceptional. We present the case of a 63-year-old man with a history of acral melanoma of the right foot (Breslow thickness 3.5 mm, BRAF wild-type) and known hepatic and cerebral metastases on computed tomography imaging. The patient underwent ileocecal resection with regional lymphadenectomy, followed by adjuvant and sequential immunotherapies including interferon-α, nivolumab, ipilimumab, and pembrolizumab. The patient subsequently underwent surgery due to ileal intussusception with creation of an ileostomy. He was admitted to our unit for anemia and vomiting. Therefore the patient underwent upper endoscopy which revealed multiple black-pigmented, vegetating lesions up to 4 cm in the gastric antrum and smaller lesions in the duodenum. Colonoscopy, performed both transanally and via ileostomy, showed dark, sessile lesions in the ileum and a small pigmented plaque in the colon. Histology confirmed metastatic melanoma (Melan-A, HMB-45, S100 positive).

Conclusion. Melanoma may metastasize diffusely to the GI tract even years after primary tumor excision. The endoscopic appearance of pigmented mucosal lesions should always prompt biopsy.

Simultaneous gastric, duodenal, ileal, and colonic metastases from melanoma are remarkably uncommon.  This case underlines the crucial role of endoscopy for diagnosis and staging of disseminated melanoma, even in advanced disease, guiding treatment decisions in complex oncologic scenarios.