Primary duodenal malignant melanoma: A case report

Abstract

Background: Melanoma is a neoplasm derived commonly from melanocytic cells of skin. Although coetaneous presentation of malignant melanoma is easily recognizable, the presentation of melanoma in other organs is so confusing. In particular, when it metastasizes to other organs, many bizarre figures and unusual organs may be involved. In this report, we present a case of primary duodenal malignant melanoma.

Case presentation: A 68-year-old man presented with a history of iron deficiency anemia. The upper gastrointestinal endoscopy showed a prominent papilla of duodenum along with an ulcerative lesion adjacent to second part of duodenum. Histopathologic evaluation showed a high-grade malignant neoplasm involving the bowel wall which was labeled for S100 protein and markers of melanocytic differentiation; Melan-A indicating the definitive diagnosis of malignant melanoma of the second portion of duodenal mucosa.

Conclusions: In patients with a history of iron deficiency anemia, any GI symptom should be evaluated carefully. However, the diagnosis of primary GI melanomas in patients without any history of melanoma is possible. Full medical investigations are recommended in these patients with primary mucosal lesions.

Keywords: Duodenum; Gastrointestinal tract; Melanoma.

Figure 1

IHC; a-d: CK, LCA, CD117, and CD34 were negative. e and f: S100 protein and Melan-A were positive. The tumor cells labeled for S100 protein and markers of melanocytic differentiation; Melan-A. As staining for CK, LCA, CD117, and CD34 were negative, the diagnosis of carcinoma, lymphoma and gastrointestinal stromal tumor were ruled out (red arrows showing the tumoral cells)

Figure 2

Histopathologic evaluation with H&E staining; a high-grade malignant neoplasm involving the bowel wall. Tumor was composed of sheets of loosely cohesive pleomorphic cells with prominent nucleoli and eosinophilic cytoplasm (red oval shape represents region occupied by tumor cells where the red arrow showing the tumoral cell).

Figure 3

Abdominopelvic computed tomography (CT) scan with intravenous contrast; Abdominopelvic computed tomography (CT) scan with intravenous contrast revealed multiple abnormalities. CT scan exhibited an ovaloid mass in the gallbladder with washout in delayed phase that was suggestive of a tumoral lesion. There were two small nodules in the right adrenal and a heterogeneous hypodense mass (diameter: 3.2 cm) in the left adrenal. In the proximal (and to a lesser extent in distal) loops of the small intestine, a heterogeneous increase in thickness was also observed. Moreover, there were several mesenteric lymphadenopathies along the superior mesenteric artery (figure 3)