LEIOMYOMATOSIS WITH VASCULAR INVASION - A UNIFIED PATHOGENESIS REGARDING LEIOMYOMA WITH VASCULAR MICROINVASION, BENIGN METASTASIZING LEIOMYOMA AND INTRAVENOUS LEIOMYOMATOSIS

Three uterine leiomyomas with vascular invasion (LWVI), two of which w ere associated with pulmonary leiomyomatous nodules, and a case of int ravenous leiomyomatosis (IVL) invading the vena cava and extending to the right atrium, are described. Despite their histological benignity, these lesions have a strong tendency to metastasize and are closely r elated to the so-called benign metastasizing leiomyoma (BML). From a c linical point of view, the pulmonary nodules of LWVI are stable or slo wIy-growing. The IVL was a ''worm-like'' tumour that presented as a ca rdiac mass. On the basis of their histological and immunohistological features, a unified histogenetic view of LWVI, IVL and BML of the uter us is proposed. LWVI and BML may be the same pathological entity and m icroscopic vascular invasion may represent the metastatic mechanism of BML. Alternatively, LWVI may be the initial stage of TVL. In rare ins tances, IVL may be associated with distant parenchymal (pulmonary) met astases. LWVI seems to be the precursor of both BML and IVL.