Extramedullary hematopoiesis in hemoglobin E/β-thalassemia

Extramedullary hematopoiesis in hemoglobin E/β-thalassemia
Author: Pritish Chandra Patra; Priyanka Samal
Category: Red Cell: Disorders of Iron Metabolism and Heme Synthesis > Hemochromatosis > x linked (and other) hereditary sideroblastic anmia > Conditions of ineffective erythropoiesis > Hemoglobin E/β-Thalassemia
Published Date: 08/24/2020

A 25 year old male, a known case of non transfusion dependent hemoglobin E/β-thalassemia, five years post splenectomy with history of portal vein thrombosis presented to emergency department complaining of breathlessness since 2 days. The complete hemogram was as follows; Hb: 5.6 gm/dl, total leukocyte count: 25750/cumm, platelet: 391000/cumm, neutrophils: 54%, lymphocytes: 40%, monocytes: 4%, eosinophils: 2% and 130 nucleated RBCs per 100 WBCs. On examination liver was enlarged 4 cm below right costal margin.

Radiograph of thorax done in the emergency as shown in figure demonstrates expanded sternal ends of almost all ribs (more prominent on right side) with widening of paravertebral region, suggestive of extramedullary hematopoiesis. On further evaluation no evidence of pulmonary embolism was found. He improved after transfusion of packed red cells.

Ineffective erythropoiesis in NTDT patients leads to expansion of the haematopoietic tissue besides liver and spleen, mostly in the form of masses termed extramedullary haematopoietic pseudotumours. The prevalence of extramedullary haematopoietic pseudotumours is higher in NTDT (~20%) than regularly-transfused β-thalassaemia major patients (<1%) and is mainly reported in β-thalassaemia intermedia and hemoglobin E/β-thalassemia patients. Among the various organs affected, paravertebral involvement has the potential to cause neural element compression but expansile ribs have hardly any direct clinical consequence.