Malignant mixed müllerian tumor of the ovary: imaging findings

We describe the imaging findings of malignant mixed müllerian tumor (MMMT) of the ovary, which have not previously been reported.

We experienced 13 cases of ovarian MMMT in eight patients. All patients underwent surgical resection and the MMMTs were confirmed pathologically. US (n = 8), CT (n = 8), and MRI (n = 1) examinations were performed before operation. Imaging features were analyzed retrospectively for bilaterality, tumor solidity (cystic or solid), size, and contrast enhancement of the tumor on CT and MRI. Presence of ascites and other evidence of peritoneal seeding, adjacent organ invasion, distant metastasis, and surgical staging were also evaluated.

There were bilateral ovarian MMMTs in five patients and unilateral MMMTs in three patients. Two of the MMMTs were multiseptated cystic, and 11 were mixed (solid and cystic). The diameter of the largest dimension was less than 5 cm in one case, 5-10 cm in two cases, and larger than 10 cm in 10 cases. Dense homogeneous contrast enhancement of the solid component was seen in 11 mixed masses. Ascites were found in all patients. Other evidence of peritoneal seeding and direct invasion into adjacent organ such as the uterus or sigmoid colon was seen in five patients each. Pleural metastasis was present in one patient. Surgical stages were FIGO classification IIIb and IV in one patient each, and IIIc in six patients.

Ovarian MMMTs usually present as aggressive, bilateral, large, solid and cystic tumors, combined with ascites, frequent peritoneal seeding, and adjacent organ invasion.