Female, 44 years old, with a history of excision of nodular malignant cutaneous melanoma on the left shoulder (Breslow: 3.9 mm; Clark level IV; pT3bN0M0) in 1998. She was treated with interferon for one year. Controls every 6 months were negative. At 5 years of age, she was admitted to the surgical department for an episode of intestinal occlusion. Abdominal CT scan: invagination of the small intestine. Treatment: urgent surgical intervention: segmental resection of the ileum due to an intraluminal tumour affecting the serosa. More polypoid tumours were palpated but not resected, as no perioperative diagnosis was available during emergency surgery. The postoperative course was correct and without complications.
Macroscopic examination: smooth, rosy serous surface, preserved folds and two tumours partially occupying the lumen (3.5 x 1.5 x 1.5 x 4 cm and 1.2 x 1 x 1 x 1 cm). When cut, the surface was solid, homogeneous, brownish with blackish areas and the consistency was soft.

Microscopically: cells with large, eosinophilic or clear cytoplasm with a vesicular nucleus and prominent nucleolus. Focally there was melanin in the cytoplasm. Abundant mitoses were observed. The tumour cells ulcerated the mucosa and diffusely infiltrated the entire intestinal wall and focally the mesentery and in other areas occupied vascular lumina. The tumour cells were positive for the monoclonal antibodies HMB 45 and S-100 protein.
Based on the clinical information, the histological image and the result of immunohistochemistry, the definitive diagnosis was metastasis in the small intestine of known cutaneous melanoma.
A study was started to assess the surgical option for salvage: small bowel transit, which revealed at least two more lesions in the jejuno-ileal junction, and a PET scan showing uptake in the abdominal midline, with the rest of the study being normal.
The patient was readmitted. Intestinal resection of two segments of jejunum and ileum respectively was performed, leaving the patient macroscopically free of disease. The pathological study showed that the tumours had the same histological characteristics as described above.