INTRODUCTION

Malignant melanoma is one of the most aggressive cancers. It primarily affects the skin and has a strong metastatic potential, involving multiple organs and systems such as the gastrointestinal tract. Within the digestive system, the small intestine is the most common metastatic site, followed by the stomach, although overall incidence remains low.

CASE REPORT

A 68-year-old male, active smoker, with a history of nodular melanoma on the back (Breslow index 3.7 mm and Clark level III), resected in 2020 with clear margins and no evidence of malignancy in three right axillary sentinel lymph nodes. He later developed pulmonary metastases that were treated with anti-PD1 therapy, achieving complete radiological response. A follow-up abdominal CT scan revealed an apparent polypoid mural thickening with lobulated contours in the gastric antrum, measuring approximately 5 cm in its longest axis. Upper endoscopy with biopsy was performed, and histology confirmed metastatic melanoma. A subsequent endoscopic reassessment demonstrated a pedunculated lesion, which was completely resected and removed endoscopically (in fragments).

DISCUSSION

The gastrointestinal tract is among the most frequent sites of melanoma metastasis. The most affected organs are the small intestine (51–71%), followed by the stomach (27%), colon (22%), and esophagus (5%). Clinical symptoms of gastric melanoma are nonspecific and, in many cases—like our patient—may be absent. Most common presenting features include abdominal pain, gastrointestinal bleeding, nausea, vomiting, anemia, and weight loss. In this case, routine imaging surveillance allowed early detection and treatment of the lesion. It is estimated that up to 60% of patients who die from melanoma have gastrointestinal metastases; however, only about 4.4% are diagnosed before death due to the frequent absence of symptoms.