Malignant melanoma (MM) is one of the most common tumours that metastasises to the gastrointestinal (GI) tract. The small intestines are the most common site for this metastasis; however, the stomach is also a rare site [1, 2].
A 58-year-old male patient applied to the gastroenterology outpatient clinic with nausea and epigastric pain. He had a history of localised cutaneous MM excision from the right thigh 5 years earlier. Lab work showed no significant abnormality on blood biochemistry. His esophagogastroduodenoscopy showed multiple, black-pigmented lesions of various sizes (Figure 1). A biopsy from these lesions revealed MM metastasis (Figure 2).
Figure 1.
A–C. Malignant melanoma metastasis in stomach; diffusely spread black-pigmented lesions at gastric mucosa in esophagogastroduodenoscopy
Figure 2.
A – Gastric mucosa with evident black pigmentation (haematoxylin and eosin stain, 100×). B – HMB-45 positivity in neoplastic cells (immunohistochemical stain, 200×)
Malignant melanoma may involve the GI tract as a metastatic lesion, or rarely as a primary tumour. Gastrointestinal tract metastasis can be seen synchronous with the primary tumour, or as a recurrent tumour years later [1, 2]. Gastric involvement may be seen as a black-pigmented ulcer or as diffusely spread black-pigmented lesions, as in our case [3]. However, a histopathological exam may not differentiate a primary lesion from a metastatic one [4]. Immunohistochemistry should be employed to prove MM with markers such as HMB-45 and S100 [5]. Treatment options for metastatic involvement of the GI tract with MM are surgery, chemotherapy, immunotherapy, and palliative therapy. Only surgery is reported to increase survival to some extent [1].
As a result, because MM metastasis may show up years later, we suggest screening of GI tract in MM patients if there is the presence of GI symptoms.
Conflict of interest
The authors declare no conflict of interest.
References
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