AbstractIntroduction: Bone marrow fibrosis is a common morphological finding in trephine biopsies. It can be of various grades and severity in various lesions. The reticulin and collagen fibers are identified by using reticulin and trichrome stains. There is a wide variety of benign and malignant disorders that are associated with bone marrow fibrosis. Materials and Methods: This retrospective study was done in the department of Pathology, Sri Ramachandra Medical college and Research Institute, Chennai- a tertiary care center. All bone marrow biopsies received in our department from June 2013 to May 2015 were analyzed. All cases with increased marrow fibrosis were included. Clinicopathologic analysis of patients identified with marrow fibrosis was done. Their clinical examination findings, hematological picture and histomorpholgical findings were analyzed. Reticulin and Massons trichrome stains were done to grade the fibrosis and collegenosis. Results: 18 patients were identified with bone marrow fibrosis in the 2 year period. The patients ranged from 14 years to 70 years of age. M:F ratio was 4:5.Among them 9 of them presented with complaints of weakness and fatiguability. They had cytopenias, and splenomegaly. The peripheral smear had leucoerythroblastic picture in 5 of these patients. They were suspected to have Primary Myelofibrosis and were advised JAK2V617F mutational analysis and BCR-ABL gene analysis.JAK2V617F was positive in 4 of them.3 of the patients were on chemotherapy. One was diagnosed with acute lymphoid leukemia, other with non hodgkins lymphoma and the other with acute myeloid leukemia. Bone marrow fibrosis was seen in a patients in autoimmune disorders including, autoimmune hemolytic anemia, pernicious anemia, and in patients with anti-nuclear antibody positivity and hypertrophic psoriasis. The H andE sections of bone marrow in 2 cases of CML were cellular having increased myelopoeisis with eosionophilia. The marrow of MDS patients had dyspoeitic features.

Keywords: Bone marrow fibrosis, Primary myelofibrosis, secondary myelofibrosis, Reticulin silver stain, Trichrome stain.