Autoimmune myelofibrosis: report of three cases and review of the literature.

Autoimmune myelofibrosis is a distinct clinicopathological entity, recognizing immunopathogenetic mechanisms and occurring isolately or in association with systemic and/or organ-specific autoimmune diseases. It results in chronic cytopenias, and is defined by a pattern including bone marrow, peripheral blood, serological and clinical features. It has to be distinguished from other disorders having myelofibrosis. Among these, the most relevant differential diagnosis is with chronic idiopathic myelofibrosis, particularly when disclosing autoimmune clinical and/or laboratory features as epiphenomenon related to a secondary immune-dysregulation. Here we report on 3 patients admitted because of chronic cytopenias. In all of them, the clinicopathological evaluation essentially demonstrated myelofibrosis, not clustered megakaryocytes, reactive lymphoid infiltration in marrow biopsies, absence of significant tear-drop poikilocytosis and leukoerythroblastosis on peripheral blood smears, normal-sized spleen, positive autoimmune serology. The resulting patterns met the diagnosis of autoimmune myelofibrosis occurring isolately in a patient and associated with Sjögren's syndrome or concomitant Sjögren's syndrome and Hashimoto's thyroiditis in the other two, respectively. Transient improvements in cytopenias and unmodified myelofibrosis were observed following corticosteroid treatment. It is noteworthy the lack of a specific therapy, being the underlying pathophisiology of myelofibrosis still unclear. In conclusion, increased awareness of the clinicopathological pattern identifying autoimmune myelofibrosis is recommended in order to improve basic and clinical knowledge of this emerging entity.