MRI features of ovarian metastases from appendiceal tumors and primary ovarian mucinous carcinoma: a comparative study

OBJECTIVE: To identify the MRI characteristics of ovarian metastases from appendiceal tumors (OMAT) and compare them with the features of primary ovarian mucinous carcinoma (POMC). MATERIALS AND METHODS: This retrospective study included 49 patients with histopathologically confirmed, MRI-detectable, and unruptured OMAT (14 patients with 18 lesions) or POMC (35 patients with 36 lesions) who underwent preoperative MRI. Clinical and MRI findings of the two groups were reviewed and compared. RESULTS: OMATs were smaller than POMCs (median diameter, 129 vs. 182 mm, p < 0.01). Lesion configurations differed between OMATs and POMCs, with the following distributions: purely solid (11% vs. 0%), solid with cystic components (17% vs. 0%), cystic with mural nodules (11% vs. 61%), and purely cystic (61% vs. 39%) (p < 0.01). Among cystic lesions, faint septa (94% vs. 31%, p < 0.01) were more frequent in OMATs than in POMCs, whereas T1-hyperintense cysts (25% vs. 81%, p < 0.01) and a stained-glass appearance (25% vs. 72%, p < 0.01) were less frequent in OMATs than in POMCs. Peritoneal dissemination (71% vs. 11%, p < 0.01) and abnormal ascites (93% vs. 11%, p < 0.01) were also more frequent in OMATs than in POMCs. CONCLUSION: OMATs tended to present as smaller, purely cystic lesions with faint septa, whereas POMCs were characterized by larger cystic lesions with T1-hyperintense cysts and a stained-glass appearance.