Indiana University School of Medicine Indianapolis, Indiana
Maria Khlebnikova, Glen A. Lehman, MD, Mark A. Gromski, MD; Indiana University School of Medicine, Indianapolis, IN
Introduction: Malignant melanoma is a potentially fatal skin neoplasm. Most of the gastrointestinal tract metastasis come from a primary skin lesion, although rare cases of primary duodenal melanomas have been reported. 50% of patients presenting with GI tract involvement also exhibit extra-intestinal manifestations of disease. The small intestine is the most commonly involved out of the GI organs, followed by the stomach and large intestine. The clinical presentation of metastatic melanoma to the small intestine often mimics symptoms of GI tumors or ulcerative lesions. Presenting symptoms may include intermittent coffee-ground emesis and severe iron deficiency anemia. Melena and abdominal pain have also been reported, as well as non-specific symptoms such as nausea, anorexia, fatigue, and weight loss. This is a unique case of an incidentally found duodenal melanoma for a patient who had a history of recent necrotizing pancreatitis.
Methods: A 42-year-old woman with a history of pancreas divisum presented for management of acute necrotizing pancreatitis. An ERCP performed for sphincterotomy of the minor papilla and stent placement revealed multiple 2-15 mm blue pigmented, slightly friable sessile and semi-pedunculated polyps on the descending and transverse duodenum (Figure 1 A,B). An H and E Stain of the duodenal polyp showed melanoma cells forming nests underneath benign mucosa (Figure 1C). The neoplastic cells were also reactive on Melan A stain (Figure 1D), S100 and SOX10 stains. On subsequent physical examination, a 2.3 x 2.8 mm thin plaque suspicious for the primary lesion was found on the left medial thigh, and skin biopsy showed dermal melanoma. Brain MRI was significant for four brain lesions. Chest CT showed multiple bilateral pulmonary nodules concerning for metastatic disease. The patient was diagnosed with stage IV BRAF+ melanoma. She had no prior symptoms related to the duodenal, brain, or pulmonary lesions, and reported no family history of skin cancer. She had a prolonged hospital course due to complications related to pancreatitis, including development of peri-pancreatic fluid collections, pericardial effusion and acute hypoxemic respiratory failure. She eventually recovered and was discharged to begin radiation treatments for metastatic melanoma. Discussion: In the unique case described here, metastatic melanoma was found incidentally from duodenal polyp resection. Prognosis is poor for patients with metastatic melanoma to the GI tract, with 5-year survival being 10-14%.
Figure 1: A & B: endoscopic images showing pigmented duodenal polyps. C: H&E stain, melanoma cells forming nests underneath benign mucosa. D: Melanoma cells staining with Melan A.
Disclosures: Maria Khlebnikova indicated no relevant financial relationships. Glen Lehman indicated no relevant financial relationships. Mark Gromski indicated no relevant financial relationships.