Hepatic sinusoidal fibrosis in agnogenic myeloid metaplasia.

Autopsy studies in two patients who had agnogenic myeloid metaplasia of long duration revealed significant extramedullary hematopoiesis in the liver associated with significant hepatic perisinusoidal/sinusoidal fibrosis. Fibrosis was nonzonal and irregularly distributed throughout the livers. Early changes were found in areas with normal parenchymal architecture and showed significant thickening of collagen fibers surrounding the liver cell plates. In areas with extensive fibrosis, coarse collagen fibers filled the sinusoidal space and resulted in the loss of hepatocytes, but nodular regeneration was absent. Hepatic perisinusoidal/sinusoidal fibrosis in livers with extensive extramedullary hematopoiesis may be more common than previously recognized.