Abstract
BACKGROUND Autoimmune myelofibrosis (AMF) is a rare clinicopathologic entity of bone marrow fibrosis that occurs in association with autoimmune disorders. Steroids are very effective for treatment of AMF and the disease has a good prognosis and should be distinguished from primary myelofibrosis. CASE REPORT A 49-year-old man with bleeding and petechial hemorrhage of the extremities presented to our institution. His platelet count was 1×10⁹/L. Bone marrow aspiration revealed a dry tap, and bone marrow biopsy confirmed small lymphocyte infiltration and increased reticular fibers, consistent with immune thrombocytopenia. Testing for mutations in JAK2, MPL, and CALR was negative. Because the patient had a history of Raynaud's phenomenon, he was suspected to have collagen disease. Anti-Sjögren's-syndrome-related antigen-A antibody testing, Schirmer's test, and fluorescein staining all came back positive, which led to a diagnosis of Sjögren's syndrome. Given the bone marrow findings, the patient also was diagnosed with AMF. Treatment with steroids resulted in an immediate improvement in his platelet count. CONCLUSIONS In the present case, treatment with steroids resulted in prompt improvement in platelet counts and subsequent marrow biopsy showed MF-0 reticulin fibrosis. Bone marrow fibrosis rarely is seen in association with autoimmune disease, and its significance and mechanism are still to be determined.