Anterior mediastinal epithelioid hemangioendothelioma associated with myelolipoma and extramedullary hematopoiesis mimicking a mature teratoma: A radiologic-pathologic correlation

Abstract

Epithelioid hemangioendothelioma (EHE) is an ultra-rare vascular neoplasm with variable biologic behavior. Mediastinal EHE is particularly uncommon and may mimic more prevalent prevascular mediastinal tumors. We report a 52-year-old man with a 10.5 × 8.9 × 9.6 cm mixed-density left upper anterior mediastinal mass containing macroscopic fat, soft-tissue components, and coarse calcification. FDG PET/CT demonstrated mild-to-moderate uptake (SUVmax 4.8) without nodal or distant metastatic disease, and the imaging appearance favored mature teratoma. Resection demonstrated a 9.5 cm conventional EHE intimately associated with a myelolipomatous component containing extensive extramedullary hematopoiesis and metaplastic ossification. The neoplastic cells expressed endothelial markers, and RNA fusion analysis detected WWTR1::CAMTA1. Surgical margins were negative, early postoperative and abdominopelvic imaging showed no residual or metastatic disease, and multidisciplinary review recommended surveillance without adjuvant therapy. Although similar EHE–myelolipoma/extramedullary hematopoiesis associations have been reported, this case emphasizes the multimodality imaging mimic of mature teratoma and provides direct radiologic-pathologic correlation of the fat-containing, solid, and ossified components.