Primary gastric melanoma presenting with recurrent upper gastrointestinal bleeding

Abstract

Malignant melanoma of the gastrointestinal tract is usually a metastasis from a cutaneous source. Primary gastric melanoma is an extremely rare clinical entity, with few reported cases worldwide. It is often advanced at the time of diagnosis and is associated with a poor outcome. We report a case of a 57-year-old male who presented to the emergency department with complaints of fatigue, haematemesis and melena. Laboratory investigation indicated a haemoglobin level of 7.4g/dl, for which the patient received a transfusion. Upper gastrointestinal endoscopy revealed a bleeding mass in the body of stomach which provisional histology was suggestive of a malignant mesenchyimal tumour but subsequent cytomorphology and immunophenotyping were consistent with malignant melanoma, with positive S-100, HMB-45 and Melan-A. Dermatological exam indicated two lesions suspicious for the primary site of metastasis but were ultimately diagnosed as benign lesions, one junctional nevus and other one seborrheic keratosis, on biopsies. Ophthalmologic exam showed no other probable sites of origin. PET/CT showed accumulation of tracer in the stomach, jejunum and perigastric lymph nodes. For this reason, primary advanced gastric melanoma was suspected in this patient. Since the patient had recurrent upper gastrointestinal bleeding that required frequent blood transfusion, a total gastrectomy with partial small bowel resection was performed. We report this case to present initial diagnostic challange and discuss performing surgery for recurrent tumour bleeding