Intravenous leiomyomatosis of the uterus: A clinicopathologic analysis of 13 cases with an emphasis on histogenesis.

The object of this study is to investigate the prognosis and potential histologic origin of uterine intravenous leiomyomatosis (IVL). We retrospectively analyzed the clinicopathologic and immunohistochemical features of 13 cases of IVL from a single institute. The patients underwent hysterectomy (3 with bilateral salpingo-oophorectomy, and 8 with excision of the broad ligaments and/or parametrium). They survived with no evidence of disease for 6-90 months. Intravascular worm-like plugs were macroscopically identified in the myometrium in 10 of 13 cases (76.9%). Six patients (46.1%) had extra-uterine involvement. Histopathologically, the intravascular tumor foci were covered with endothelium. We found the presence of congested vessels in the tumor and the surrounding myometrium in 9 of 13 cases (69.2%). The concurrent entities included seven uterine leiomyomas, one leiomyoma with adenomyosis, one adenomyosis, and one pulmonary benign metastasizing leiomyoma. Estrogen receptor and desmin were positive in IVL, and negative in the vascular wall. We conclude that IVL confined to the uterus may have a favorable prognosis, and we believe IVL is likely to originate from contiguous leiomyoma or myometrium.