Uterine smooth-muscle tumors with unusual growth patterns: Imaging with pathologic correlation

OBJECTIVE. This essay illustrates the salient features of variant smooth-muscle tumors on multiple imaging techniques with correlative pathology. We describe how recognition of these features allows the radiologist to distinguish a uterine leiomyoma variant from the classic fibroid or a leiomyosarcoma. Finally, we highlight the role of the radiologist in triaging these patients to surgical versus medical management and in surgical planning. CONCLUSION. Parasitic leiomyoma, intravenous leiomyomatosis, disseminated peritoneal leiomyomatosis, and benign metastasizing leiomyoma show key features on multiple imaging techniques that correlate with pathology findings. In the appropriate clinical setting, the radiologist should include these unusual lesions in the broader differential diagnosis of smooth-muscle tumors and, in certain cases, aid in surgical planning.