Intracranial Hematopoiesis in Beta Thalassemia: A Case Series

Abstract

Extramedullary hematopoiesis (EMH) is a normal response to failure of hematopoiesis at its normal site i.e., bone marrow. It is a manifestation of many congenital hemolytic anemias and marrow failure secondary to myelodysplastic syndromes. Usually, extramedullary myeloid proliferation occurs in liver, spleen and lymph nodes. However, there are many unusual sites where EMH can occur. The authors report two cases of intracranial extramedullary hematopoiesis in beta thalassemia. In one of these patients, epidural soft tissue was detected along frontal and parietal convexities causing compression of brain parenchyma leading to raised intracranial tension and sagging of brain stem, corpus callosum and herniation of cerebellar tonsils. The other case had a similar but unilateral epidural soft tissue. Expansion of diploic spaces of skull was seen in both these cases. As myeloid proliferation is slow, it presents with subtle symptoms of headache and gradually progressive lower limb weakness. A high index of clinical suspicion coupled with imaging findings is the only way to confirm the diagnosis.

Neuroimaging Findings in Pediatric Patients with Thalassemia Major

“…We found ischemic foci in the cerebral white matter in 3 of our patients. In recent studies, thromboembolic events were reported with a rate of 0.9–29% in thalassemia patients [ 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. These ischemic foci that we saw in our patients were minimal areas due to microemboli.…”

“…Dural thickening due to extramedullary hematopoiesis is extremely rare. Studies of dural thickening resulting from intracranial extramedullary hematopoiesis in children with thalassemia are generally at the level of case reports [ 18 , 19 ]. In our study, we detected dural thickening in 1 patient.…”

Cerebral intraparenchymal extramedullary hematopoiesis in polycythemia vera

“…Extramedullary hematopoiesis (EMH) is a compensatory physiological response of the organism to the failure of hematopoiesis at the bone marrow, which occurs commonly in patients with chronic hemolytic anemia or diseases with ineffective erythropoiesis [3]. Usually, extramedullary production of blood precursor cells occurs in the spleen, liver, or lymph nodes.…”

“…However, cases with EMH in the adrenals, thymus, pleura, skin, gastrointestinal tract, and paranasal sinuses have been described [4]. Intracranial EMH is extremely rare, and only cases involving the dura mater have been described [3]. To the best of our knowledge, no cases of intracranial intraparenchymal EMH have been described.…”

“…Common sites of EMH are the liver, spleen, and lymph nodes. To date, cases of intracranial EMH have been described only in the form of extra-axial, epidural, or subdural, mass-like lesions [3]. The majority of the published cases were asymptomatic, presenting with symptoms only in cases of elevated intracranial pressure due to a tumor-like mass [5].…”