ANGIOMYOLIPOMA OF THE LIVER - A COLLECTIVE REVIEW

This review summarizes the clinical and pathological findings of 52 ca ses of hepatic angiomyolipoma to discern and establish the most pertin ent clinical and pathologic characteristics of the tumor. The disease was symptomatic in 60% of the patients. Abdominal pain or distress was the most common symptom, appearing in 37% of the patients, followed b y malaise and upper abdominal mass or hepatomegaly. Of the 52 patients , only three (5.8%) showed associated tuberous sclerosis. Antemortem d iagnosis of the tumor has been made with increasing frequency with the recent advent of computed tomography (CT) and ultrasound (US). The tu mor was usually visualized as a hyperechoic mass by US imaging and as a low density mass less than -20 Housefield units by CT, and was hyper vascular on angiography. The tumor was usually yellow to light tan, de pending on the amount of fat tissue. Histologically, the tumor was cha racterized by an admixture of mature fat cells, blood vessels, and smo oth muscle cells, with occasional foci of extramedullary hematopoiesis . The aumount of smooth muscle component varied and often exhibited hy percellularity, pleomorphism with occasional bizarre giant cells, and moderate mitotic activity. These features are considered conducive to an erroneous diagnosis of malignant tumor. However, since no malignant counterpart has been reported, it can easily be accurately differenti ated histologically, if one is aware of the entity and can identify th e three components of the tumor; blood vessels, smooth muscle cells, a nd fat. With regard to the histogenesis of angiomyolipoma, primitive m esenchymal cells around blood vessels may be the precursor cells.