Intravenous leiomyomatosis of the uterus

Intravenous leiomyomatosis is a rare uterine tumor defined as an intraluminal growth of benign smooth muscle cells in either venous or lymphatic vessels outside the confines of, or even in absence of leiomyomas. We report a case of intravenous leiomyomatosis of the uterus managed at our institution.

The patient, a 47-year-old woman; gravida 2 para 2, presented without complaints for a routine gynecological examination. An irregular-shaped enlarged uterus with a nodular pelvic mass extending into the broad ligament was found Laparotomy revealed a large retroperitoneal, moderately firm tumor which demonstrated fingerlike projections into the pelvic veins. Due to great blood loss, surgery had to be discontinued with substantial residual disease and our patient was set on a regimen of the GnRH analogue Leuprolide, which was applied over 5 months. This led to a reduction of the tumor which facilitated successful surgery. The primary tumor as well as the residual disease were classified as a leiomyoma with intravenous extension consisting of uniform, spindle-shaped smooth muscle cells in a whorled arrangement. Mitotic activity was low and pleomorphism was missing. Areas with degenerative changes were found, as well as prominent vascularity. At the right parametrium, the lumina of the dilated veins were filled with tumor. Immunhistochemically, the intravascular parts of the tumor revealed a positive staining reaction for vimentin, desmin and alpha-smooth muscle actin. The tumor also reacted for antibodies against estrogen- and progesterone-receptors.

Knowledge about this rare uterine tumor is important for adequate treatment and exact differential diagnosis. Though intravenous leiomyomatosis imitates a malignant neoplasm regarding its pattern of growth and extension, it must be differentiated histologically from malignant tumors to prevent overtreatment. Since intravenous leiomyomatosis demonstrates a tendency to recur, long-term follow-up of the patient is recommended.