Unveiling a Rare Cause of Dysphagia.

Introduction: Malignant melanoma of the esophagus is an uncommon cause of dysphagia and accounts for only 0.1-0.2% of esophageal neoplasms. Diagnosis is based on esophagogastroduodenoscopy (EGD) with biopsies and immunohistochemical analysis, the latter being crucial in the amelanocytic variant. Gastrointestinal melanomas are more invasive and comprise poorer prognosis than cutaneous melanomas. Case Presentation: The authors present the case of a 70-year-old woman admitted to the emergency department for progressive dysphagia with 2 months of evolution. EGD revealed the presence of an extensive, eccentric lesion, occupying approximately half of the luminal circumference at the level of the distal esophagus with circumferential involvement of the esophagogastric junction and cardia. Thoracoabdominopelvic computed tomography and positron emission tomography showed signs of advanced disease. The initial endoscopic biopsies were inconclusive, and EGD was repeated with multiple biopsies directed at the most infiltrative areas, whose histopathological analysis with immunohistochemistry revealed neoplastic cells with marked nuclear positivity for SOX10 and cytoplasmic positivity for vimentin, Melan-A, and HMB45 with absence of melanin pigment, findings suggestive of esophagocardiac amelanocytic malignant melanoma. In a multidisciplinary team meeting, the neoplasm was deemed unresectable, and the proposal was for esophageal stent placement and palliative hormone therapy. Discussion: Primary amelanocytic malignant melanoma is an exceptionally rare neoplasm and an extremely uncommon cause of dysphagia. In this context, we present a compelling case study that underscores the rarity of this histological type, the importance of directing biopsies to the most suspicious areas of the lesion to increase diagnostic yield, the need for a high clinical suspicion, and the atypical endoscopic presentation associated with the amelanocytic subtype.