Shining Light on Rarity: Mucoepidermoid Carcinoma of the Esophagus with Absence of MAML2 Gene Rearrangement.

Primary mucoepidermoid carcinoma of the esophagus is a rare condition characterized by a combination of squamous and mucin-secreting glandular malignant cells. Its clinical recognition is often challenging, pre-operative diagnosis is difficult, and there is a lack of standardized treatment protocols. Here, we present the clinicopathological characteristics of a previously underreported esophageal malignancy found in the distal esophagus of a 58-year-old woman. The initial endoscopic biopsy posed diagnostic challenges due to its small size and inadequate representation of glandular differentiation components making a final diagnosis of poorly differentiated squamous cell carcinoma. Recognizing the resectability of the tumor prompted surgical removal, revealing islands of squamous cells along with intermediate cells and mucin pools. Additionally, MECs in majority of the cases show MAML2 gene rearrangement; contrarily, the present case showed negative results. Enhanced clinicopathological awareness of esophageal MEC facilitated a definitive diagnosis and better patient management. It is imperative to increase awareness and globally document cases of esophageal MEC to enhance understanding, diagnosis, and management guidelines for this malignancy in this anatomical location.