Cystic Fluorodeoxyglucose-Avid Thymic Hyperplasia with Lymphoepithelial Sialadenitis-like Features

Thymic hyperplasia with lymphoepithelial sialadenitis-like features (LESA-like TH) is a rare benign thymic lesion sometimes associated with autoimmune diseases or mucosa-associated lymphoid tissue lymphoma. A 47-year-old man was incidentally found to have 2 anterior mediastinal masses. Contrast-enhanced computed tomography (CT) showed irregularly walled cysts, and positron emission tomography-CT demonstrated partial fluorodeoxyglucose (FDG) uptake. A total thymectomy was performed, and histopathology confirmed LESA-like TH. This is the first report to document both imaging-visible multiplicity and FDG avidity in LESA-like TH, which broadens the recognized imaging spectrum of this rare thymic lesion.