Computed tomography and magnetic resonance imaging findings in cases of dermoid cyst coexisting with surface epithelial tumors in the same ovary.

Objective: The purpose of this work was to describe the computed tomography (CT) and magnetic resonance imaging (MRI) findings in cases of dermoid cysts coexisting with surface epithelial tumors in the same ovary. Methods: The pathologic reports of 141 dermoid cysts, 97 mucinous and 35 serous tumors were reviewed. The CT and/or MR images in the cases with a dermoid cyst and a surface epithelial tumor coexisting in the same ovary were analyzed. Results: Eleven cases of mucinous tumors (6 benign, 3 low-grade, and 2 malignant) coexisted with dermoid cysts. Mucinous tumors were found in coexistence with 11.3% of dermoid cysts, and dermoid cysts were found in coexistence with 7.8% of mucinous tumors. In 10 cases, 3 radiologic patterns were observed: small fatty foci in the septa of the cystic tumor, an adjacent fat-containing component and a septated cystic component, and a dermoid cyst with no detectable mucinous tumor component. No histopathologically specific differences were observed between these groups. Small amounts of mucinous components were difficult to detect, but small fatty foci were easily detected. In 1 case, mucinous carcinoma formed a mass lesion in the wall of the dermoid cyst. Conclusions: The coexistence of these two neoplasms was not rare. If a dermoid cyst accompanies a multiseptated cyst and if the multiseptal cyst contains fatty foci, these two components may be associated. Recognizing the potential for the coexistence of these two neoplasms in the same ovary is essential for making a correct diagnosis.