Distinguishing autoimmune myelofibrosis from primary myelofibrosis

Bone marrow fibrosis (BMF) is a histologic finding in a wide range of diseases, including malignancies, endocrine disorders, autoimmune diseases, and infections. Autoimmune myelofibrosis (AIMF) is an uncommon etiology of BMF; it can be secondary to a defined autoimmune disease, or it can be primary in the absence of a clinically diagnosed autoimmune disease but the presence of serologic evidence of autoantibodies. Distinguishing between primary myelofibrosis (PMF) and non-neoplastic AIMF is of the utmost importance because the prognosis and therapeutic options are different. This distinction, however, can be complicated by overlapping findings in the 2 disease entities. Here, using the case of a patient with BMF in the setting of idiopathic thrombocytopenic purpura and autoimmune hemolytic anemia, we present a systematic approach to distinguishing between PMF and AIMF.