FOREIGN-BODY GIANT-CELL REACTION ASSOCIATED WITH EPIDERMOID TUMOR - CT AND MR FINDINGS

A patient with a known epidermoid tumor presented with a new large rin g-enhancing mass adjacent to the cyst. Histopathology showed foreign b ody giant cell reaction adjacent to the epidermoid cyst. The CT and MR imaging appearances are described. The neuroimaging findings are iden tical to malignant degeneration to squamous cell carcinoma.