Clinical, radiological, histological and immunohistochemical methods were used to define the nature of multiple rapidly growing hepatic nodules in 2 young patients with Budd-Chiari syndrome due to myeloproliferative diseases. In one patient, the arterial hyperperfusion of large nodules was demonstrated by dynamic computed tomography and angiography. The explanted livers of these patients showed multiple well-demarcated nodules up to 3 cm in diameter on the background of liver cirrhosis resulting from chronic hepatic congestion. Histologically, these nodules covered a spectrum ranging from adenoma-like lesions to nodules resembling focal nodular hyperplasia. They consisted of essentially normal hepatocytes, and variably contained fibrous septa including neoductules and large, mostly dysmorphic arteries. Sometimes, they were located close to still patent or recanalized veins. These rapidly growing hepatic nodules are best defined as macroregenerative nodules. The knowledge of this entity may help the physician to avoid misinterpretation of such nodules as carcinomas.