Malignant Melanoma of the Gastrointestinal Tract: Symptoms, Diagnosis, and Current Treatment Options

Abstract

Malignant melanoma (MM) has become the fifth most frequent cancer in the UK. It is the most common carcinoma to metastasize to the gastrointestinal (GI) tract. MM particularly has an affinity to spread to the small bowel, which is followed by the involvement of the stomach and large intestine. Excellent endoscopic options including video capsule endoscopy and enteroscopy are available for a precise diagnosis of GI involvement by a metastatic MM. The complete surgical resection of GI metastatic MM in carefully selected patients not only provides symptom control, but has also been associated with an increase in overall survival. The approval of BRAF-targeted therapies and immune checkpoint inhibitors has transformed therapeutic approaches for patients with metastatic MM over the past decade. Currently, the overall survival of patients with advanced metastatic MM who have been treated with a combination of immunotherapeutic agents reaches 52% at five years. The role of surgery for patients with the metastatic involvement of the GI tract with MM is evolving in the era of effective systemic treatments.

Keywords: BRAF/MEK inhibitors; gastrointestinal tract; immunotherapy; malignant melanoma.

Figure 1

High-definition white light endoscopy: Metastatic malignant melanoma involving the distal body (size: 20 × 15 mm; 1) and proximal antrum (size: 15 × 10 mm; 2) of the stomach.

Figure 2

High-definition white light endoscopy: Metastatic malignant melanoma with features of recent bleeding involving the greater curvature of the gastric body (size: 30 × 20 mm; arrows).

Figure 3

Biopsy specimen taken from the melanoma metastasis in the stomach presented in Figure 2. Haematoxyline-eosine staining (melanoma pigment—brown colour). Original magnification ×200.