Positron emission tomography and leiomyomas: Clinicopathologic analysis of 3 cases of PET scan-positive leiomyomas and literature review

IntroductionStudies have suggested that PET scans can differentiate between leiomyomas and leiomyosarcomas. Our experience, however, shows that PET scan-positive smooth muscle tumors are not necessarily malignant.Case reportsThree patients with cancer underwent PET imaging. In all three, the most worrisome finding was a PET scan-positive uterine tumor. After surgical extirpation, all three uterine tumors were found to be benign smooth muscle neoplasms.DiscussionTo explore the potential reason these tumors were positive on PET imaging, we performed a detailed histopathologic and immunohistochemical study of all specimens. Pathologic evaluation revealed a leiomyoma, a cellular leiomyoma, and a stromomyoma. There was no association between an increased Ki67 (proliferative) index and positivity on PET imaging. Increased vascularity, however, appeared to be a feature common to the leiomyomas that were PET-positive.