Cystic Intramuscular Myxoma

CT and ultrasound examination of a soft tissue mass in a 43-year-old woman revealed a large, cystic lesion. At surgery, a myxoma was found deep to a large cyst. Although myxomas have been reported frequently to contain one to 5 mm cysts, none has previously been reported associated with a large cyst that concealed the solid tumor. Large intramuscular cysts are rare; a cystic appearance on CT or ultrasound examination of an intramuscular mass should suggest a possible underlying solid lesion.