Nodular regenerative hyperplasia of the liver in a case of myelofibrosis with extramedullary hematopoiesis and secondary portal venous hypertension.

Nodular regenerative hyperplasia of the liver was identified at autopsy in a patient with myelofibrosis with extramedulary hematopoiesis, an association not previously reported. Portal venous hypertension, documented during the patient's terminal hospitalization, was ascribed, in part, to a high rate of blood flow through the enlarged spleen. Possible mechanisms accounting for the development of nodular regenerative hyperplasia of the liver, and evidence provided by this case pertinent to these mechanisms, are discussed.