Narrow band imaging appearance of gastric metastasis from malignant melanoma

A 72-year-old male patient with no co morbidities presented with progressive loss of weight and appetite. Clinical examination was unremarkable. The routine diagnostic work up including hemogram, blood biochemistry and chest skiagram were non contributory. The patient was referred to us for upper gastrointestinal endoscopy. The endoscopic examination of stomach revealed multiple black colored elevated lesions throughout the stomach (Fig. 1). Narrow band imaging (NBI) revealed presence of black colored patches on the summit of these elevated lesions (Fig. 2). The base of these elevated lesions revealed enlarged regularly placed oval and elongated pit pattern (Fig. 2). No abnormal microvascular pattern was observed. Histopathological examination of the endoscopic mucosal biopsies from these lesions revealed features of metastatic malignant melanoma. Contrast-enhanced computed tomography of the chest and abdomen revealed multiple hypodense lesions in both lobes of liver and spleen suggesting a possibility of hepatic and splenic metastasis. The patient was thereafter referred to oncology services. Melanoma frequently metastasizes to the gastrointestinal tract with the stomach being one of the common sites [1]. The autopsy series have reported gastrointestinal involvement in up to 60% of patients with melanoma but clinical detection rate before death is as low as 7%, because of silent metastasis in the majority of patients [1-3]. The symptoms of gastric metastasis are usually nonspecific like epigastric pain, nausea, vomiting and rarely upper gastrointestinal bleed [1-3]. Endoscopy is a good modality to suspect melanoma metastasis due to pigmentation and confirm with histopathology and immunohistochemistry. Endoscopic appearance of lesions of the stomach is variable and amelanotic lesions have been described in almost 50% of cases [4]. NBI endoscopy can also be helpful in the diagnosis of gastric melanoma metastasis especially of amelanotic lesions.