Objective: To present a rare entity of difficult preoperative diagnosis.
Background: Primary malignant melanoma of the esophagus represents 0.1% of all malignant tumors in this organ. It has been described in association with esophageal melanocytosis and melanosis with a clinic behavior similar to other neoplasm in the esophagus, but is more aggressive and fatal. By endoscopy, it usually appears as a vegetant, non-obstructive lesion, with dark pigmentation in the melanotic variant, the sole evidence that suggests the diagnosis prior to microscopic examination. Clinical exclusion of metastasis melanoma as a possibility is obligatory.
Methods: We reviewed clinical, imagenologic, endoscopic, and anatomopathological aspects of an ulcerovegetant neoplasm on the esophago-gastric junction, surgically resected, in a 65 years-old man with progressive dysphagia, who was without tumoral relapse during 18 months after surgery.
Results: The tumoral mass was an anaplastic cell tumor with very scant melanic pigmentation and diffuses stain for HMB-45 antigen and S100 protein, considering it to be a primary malignant melanoma. The neighboring mucous membrane showed a typical Barrett's esophagus and melanocytic hyperplasia.
Conclusions: 1) Endoscopy may suggest the possibility of esophagus melanoma when there is a vegetate, non-obstructive, pigmented tumor. 2) Immunohistochemistry confirms the entity if HMB-45 antigen and S100 protein are detected in the tumoral cells, while the negative results for keratin and leukocytic common antigen (LCA) eliminate carcinoma and lymphoma as possible diagnoses. 3) In our case, the presence of Barrett's esophagus is exceptional, because it has not been described previously in the literature reviewed.