Internuclear Bridging of Erythroid Precursors in the Peripheral Blood Smear of a Patient with Primary Myelofibrosis

©Copyright 2017 by Turkish Society of Hematology Turkish Journal of Hematology, Published by Galenos Publishing House An 84-year-old male diagnosed with primary myelofibrosis based on WHO grade 2-3 fibrosis (Figure 1) and the presence of the JAK2-V617F mutation was treated with supportive care. During 2 years of follow-up, his hemoglobin level was maintained at approximately 6.5 mmol/L and platelet count declined from 128x109/L at presentation to 50x109/L. White blood cells did not exceed 12.0x109/L, while the fraction of blast cells increased to 10%. Elevated levels of teardrop cells were observed and the nucleated red blood cell count gradually increased from non-detectable to 2.4x1012/L. Recent peripheral blood smears showed biand tri-nucleated red blood cells, and even more notably, erythroid precursors with internuclear chromatin and cytoplasmic bridging (Figures 2 and 3). In concurrence with laboratory findings, physical examination revealed progressive splenomegaly (8 cm palpable below the rib margin) and weight loss. Erythroid precursors with internuclear bridging in a blood smear is a rare morphological finding and is considered a diagnostic morphologic feature in patients with congenital dyserythropoietic anemia type I and a morphological manifestation of dyserythropoiesis in