Cotyledonoid dissecting leiomyoma is a rare benign uterine tumor whose gross and radiological appearance may raise the possibility of a malignancy. The authors summarize herein the clinical, radiological, and pathological features of the 41 previously reported cases. The patients typically presented with menorrhagia or symptoms that were ultimately relatable to the presence of a pelvic mass. The median patient age was 46 years (range 23-73). The average tumor size was 15.4 cm (range 4-41); most were exophytic, multinodular, occasionally cystic masses with a congested, spleen or placenta-like color, protruding over the uterine serosa and, variably, the broad ligaments and adjacent organs. In most cases, the exophytic component was contiguous with the intramural dissecting leiomyomatous components. Histological features suggestive of malignancy, such as cytological atypia, necrosis, or increased mitotic activity were absent. Intravascular growth, as assessed histologically, was present in 20% of reported cases, and this finding is apparently devoid of clinical significance based on limited data. Reported information on radiological features is limited. However, these lesions are typically isointense to myometrium on T1-weighted MRI and are in general less heterogeneous on T2 and postcontrast-imaging than sarcomatous lesions. The tumor may display extension to but not frank invasion of surrounding organs. Ultrasound features are nonspecific. Follow-up information was available in 25 (61%) of 41 reported patients: none experienced a tumor recurrence or metastases during the follow-up period, which ranged from 1 month to 41 years. This affirms the benign nature of this tumor, its alarming gross appearance and growth patterns notwithstanding.
