Magnetic resonance imaging and quantitative analysis of contents of epidermoid and dermoid cysts.

The intracapsular cholesterol, protein, and calcium contents of epidermoid and dermoid cysts from seven patients were compared with the signal intensities on T1-weighted spin-echo magnetic resonance (MR) images. All specimens had a paste-like consistency when resected. Epidermoid and dermoid cysts demonstrated a wide range of cholesterol and calcium contents, and epidermoid cysts were not always rich in cholesterol. Five patients had cysts with lower signal intensity than white matter, which contained more than 18.3 mg/g wet weight of protein. One of these patients had the highest cholesterol content of all seven patients (22.25 mg/g wet weight) and another had the highest calcium content (0.75 mg/g wet weight). Two patients had cysts with higher signal intensity than white matter, with protein contents of lower than 4.3 mg/g wet weight. High protein content (> 18.3 mg/g wet weight) may decrease signal intensity on T1-weighted MR images, while low protein content (< 4.3 mg/g wet weight) may increase signal intensity in epidermoid and dermoid cysts with high viscosity (paste-like consistency) contents.