Need for Re-Classifying the Rare Condition of Ectopic Hamartomatous Thymoma Based on Tumor Analysis

Abstract

Ectopic hamartomatous thymoma is a rare neoplasm with classic anatomical location and characteristic histological and immunohistochemical features. Awareness of ectopic hamartomatous thymoma is essential to accurately diagnose these lesions which clinically mimics lipoma. Based on the morphologic and immunophenotypic features, the authors stress the need to discontinue the existing term of ectopic hamartomatous thymoma and replacing it with suitable nomenclature that aptly denotes its phenotype and possible histogenesis. The authors propose a new terminology “Triphasic Epithelial Myoepithelial Mesenchymal Branchial Anlage Tumor” as it encompasses three important constituents of the lesion (epithelial, myoepithelial, and mesenchymal) and its possible histogenesis in relation to branchial remnants.