SMALL INTESTINE - Malignant melanoma

The upper specimen from the small intestine shows little abnormality other than the presence of a thin exudate on the serosa. The lower specimen shows, from the front, a diffuse infiltration of pale tissue occupying much of the thickness of the bowel wall above, but probably only the outer muscle and serosa below. The mucosa appears intact. Posteriorly the bowel is dilated producing a cyst in the wall of which tumour can be seen; to one side there is an ulcerated area in which there are flecks of dark material. No perforation can be seen, but there is exudate on the serosa of bowel indicating peritonitis.
This man presented at the age of 49 with a melanoma on the back of the right shoulder; a right-sided block dissection of the neck was made, to be followed by the removal of involved lymph nodes on the left side of the neck 2 years later. Three years after the original lesion cerebral secondaries were demonstrated; a year later he presented with severe abdominal pain; laparotomy showed peritonitis with perforation of a cystic area on the ante-mesenteric border of the proximal jejunum. Microscopy showed the presence of metastatic melanoma in the intestine.