Cases of primary malignant melanoma and melanocytosis of the esophagus observed by magnifying endoscopy: Application to differential diagnosis: case series

Abstract

Rationale: Primary malignant melanoma of the esophagus (PMME) is a rare disease with an extremely poor prognosis. In contrast, melanocytosis is a benign condition defined as melanocytic proliferation with melanin deposition. PMME is often accompanied by melanocytosis, but differentiating between them is difficult because of their similar appearance.

Patient concerns: Here, we reported 3 PMME cases, 2 with melanocytosis.

Diagnoses: Magnifying endoscopy revealed characteristic non-uniform pigmented spots along deformed intrapapillary capillary loops (IPCLs) in PMME, while melanocytosis showed fine granule-like or linearly arranged spots and intact IPCLs.

Interventions: The patients underwent endoscopic or surgical resection of each lesion.

Outcomes: Histologically, magnified images reflected melanocyte growth. For cases 1 and 2, the patients remained disease-free for 61 and 15 months after endoscopic resection, respectively. In case 3, liver metastases developed two months after surgery, and the patient died from liver failure after six months.

Lessons: This is the first report describing differences in magnified views of the 2 diseases, which aids a differential diagnosis.

Figure 1

PMME in case 1. (A) Endoscopy showing a flat, heterogeneously hyperpigmented mucosal patch with an obscure boundary. (B) Magnified image with white light revealing irregular, black, and nonuniform granule-like spots. (C) Granule-like spots were scattered along deformed IPCLs (arrow) or replaced them as shown by magnifying endoscopy with NBI. (D) Hematoxylin–eosin stain of an endoscopic submucosal dissection. Atypical melanocytes grew along the basal layer of epithelium and IPCLs, and showed junctional activity (arrow) (×50). (E) IPCLs (arrow) deformed by invading melanocytes (arrowhead) (×200). IPCL = intrapapillary capillary loop, NBI = narrow band imaging, PMME = primary malignant melanoma of the esophagus.

Figure 2

Melanocytosis of the esophagus in case 1. (A) Endoscopy revealed a view similar to PMME. (B) Magnifying endoscopy with white light revealed scattered or linearly arranged fine spots. (C) Magnifying endoscopy with NBI revealed faint, but intact IPCLs (arrow). (D) Hematoxylin–eosin stain of an endoscopic submucosal dissection. Spindle-shaped melanocytes grew along the basal layer of epithelium and IPCLs without junctional activity (×50). (E) IPCLs (arrow) surrounded by non-invading melanocytes (arrowhead) (×200). IPCL = intrapapillary capillary loop, NBI = narrow band imaging, PMME = primary malignant melanoma of the esophagus.

Figure 3

Schematic illustration of pathological structures and pathological/endoscopic findings of melanocytosis and primary malignant melanoma of the esophagus (PMME).