Teaching Case

A 63-year-old male patient with a personal history of lumbar skin melanoma stage IB in 2012 in complete response was admitted to our hospital for the study of an abdominal mass in his left hypochondrium associated with abdominal pain and vomits.

An abdominal contrast-enhanced CT showed a circumferential and heterogeneous thickening of the proximal jejunal wall with aneurysmatic dilatation of its lumen and irregular margins and nodular projections that infiltrated not only the adjacent mesenteric fat but also other jejunal and ileal loops. (Fig. 1- 2). It measured 14 x 7 x 7 cm. Neither locoregional lymphadenopathies nor data of vascular invasion were depicted.
The patient underwent an exploratory laparotomy in order to take biopsies and to support the CT findings. The laparotomy confirmed the jejunum origin of the mass and the infiltration of some distal jejunum and ileal loops, the transverse colon and the third and fourth portions of the duodenum. Because of this the tumour was considered unresectable. Due there was no obstructive component, the gastro-enteral shunt was also discarded.

Biopsy results showed melanoma metastasis.

Neoplasms of the small bowel are rare (<5% of total gastrointestinal tumours). [1] Even though there are primary ones as adenocarcinoma, GIST, or carcinoid tumour, the most common if the patient has a history of known malignancy are metastases. [1] Melanoma is the most common tumour that metastasises to the gastrointestinal tract, representing about one third of all metastases, and the small bowel is the commonest location. [2]
The prevalence of small bowel metastases of melanoma being found alive ranges from 2-5%, even though they are frequently seen in autopsies (50-60%). [3] Clinical presentation is often non-specific: abdominal pain (62%), haemorrhage (50%), nausea and vomiting (26%) and palpable mass (22%). [3] Approximately 10% of metastatic melanomas in the small bowel may act as leading points for intussusceptions and result in small-bowel obstruction. [2]

The way of presentation of metastases is variable: round masses, intraluminal polyps or annular lesions with central necrosis. [1] In our case, the aneurysmal dilatation of the jejunum lumen indicated the differential diagnosis with lymphoma, as this type of presentation is more characteristic of the latter. [1, 3] However, the absence of lymphadenopathies plus the oncological history supported the diagnosis of metastases of melanoma as the first option. The anatomopathological study, anyway, is often required to reach the final diagnosis. [3]
Surgical resection is the treatment of choice for these patients, as it improves its prognosis. [3] In our case, however, the tumour was considered initially unresectable and the patient received chemotherapy with the aim of reducing the tumour volume for a possible future resection. After 5 months, a follow-up CT was performed showing partial tumour response (Fig 3a, b, c).