Choroidal Melanoma Metastases to the Stomach and Duodenum

Choroidal melanoma is the most common type of uveal melanoma followed by melanoma of the iris and ciliary body. Unlike cutaneous melanoma which commonly metastasizes to the gastrointestinal (GI) tract, uveal melanoma has a strong predilection for hematogenous spread to the liver. We report a rare case of choroidal melanoma with asymptomatic metastases found incidentally in the stomach and duodenum. A 65-year-old woman with a history of Barrett's esophagus and choroidal melanoma was referred for esophagogastroduodenoscopy (EGD) to evaluate an abnormal positron emission tomography (PET) scan demonstrating increased uptake in the distal esophagus concerning for esophageal malignancy. Two years prior, she was diagnosed with choroidal melanoma found incidentally in her left eye during a routine evaluation for cataracts. Staging computed tomography (CT) scan was negative for metastases at that time. She was treated with radium plaque brachytherapy followed by a total of six months of sunitib 50 mg daily. Follow up PET scan one year later that showed increased uptake in the distal esophagus. Vital signs were normal and physical examination was unremarkable. She underwent diagnostic EGD that demonstrated a large hiatal hernia and Barrett's esophagus without dysplasia. In addition, two 5-mm black pigmented non-bleeding lesions were incidentally found in the gastric antrum (Figure 1) and duodenal bulb (Figure 2). Histopathological evaluation confirmed metastatic melanoma (Figure 3, duodenum, H&E stain). Immunohistochemistry stains demonstrated wild-type for BRAF, PIK3CA and NRAS. The cells were 40% positive for PD-1. The patient was started on pembrolizumab, and the patient started to receive palliative radiation for newly diagnosed dural metastases as well. She remains stable despite her advanced disease. Uveal melanoma is the most common primary intraocular malignancy in adults with a stable incidence of 4 cases per million per year. Up to 50% of patients with uveal melanoma will have metastatic disease. The most common metastatic site is liver (89% of patients) followed by lung (29%) and bone (17%). While metastases to the GI tract are very common for cutaneous melanoma, they are rare in ocular melanoma. Endoscopically, they can appear as small nodules, ulcerations, or a polypoid mass. The metastases may be pigmented or amelanotic. Treatment for cutaneous melanoma metastases is palliative surgery.2629_A Figure 1. Melanoma in Gastric Body2629_B Figure 2. Melanoma in Duodenum2629_C Figure 3. Histopathological evaluation confirmed metastatic melanoma (Duodenum, H&E stain). Immunohistochemistry stains demonstrated wild-type for BRAF, PIK3CA and NRAS. The cells were 40% positive for PD-1.