Discussion
This patient had thalassemia intermedia with splenectomy done in childhood. He required frequent blood transfusion and had iron overload, but refused iron chelation all along. The masses were due to extramedullary hematopoiesis (EMH). The extramedullary haematopoiesis even developed into intraspinal extension at T2 to T8 and L5 to S2 levels with compression of the thecal sac. Radiotherapy was required.
Extramedullary hematopoiesis refers to hematopoiesis outside of the medulla of the bone. EMH is a response to erythropoiesis failure in the bone marrow. More commonly observed areas of EMH include the paraspinal regions of the thorax, liver, and spleen. It has also been reported in other locations including the adrenal gland, bowel, dura mater, and breast, even the perirenal/ pelvicaliceal areas and the endometrium, etc. It was found that patients with hemoglobinopathies are more likely to have EMH in paraosseous locations, whereas patients with myeloproliferative disorders are more likely to have extraosseous masses.
Intrathoracic extnamedullany hematopoiesis is characterised by nonpulsatile, well circumscribed, often lobulated paraspinous masses without evidence of bony erosion. The masses usually cause no symptoms but can cause pleural effusion or hemothorax. Just as in our patient, we have performed extensive workup but could not find a cause of the effusion otherwise. This patient died of sepsis of other cause eventually.
Thalassemia intermedia is a term used to define a group of patients with β thalassemia in whom the clinical severity of the disease is somewhere between the mild symptoms of the β thalassemia trait and the severe manifestations of β thalassemia major. The diagnosis continues to be a clinical one regardless of the genotype involved.
Figure. CT thorax showing paraspinal masses and EMH from multiple pleural based nodules around ribs. Pleural effusions are seen (L>R).
Further reference
1. Edson Marchiori; Dante Luiz Escuissato; Klaus Loureiro Irion; Gláucia Zanetti; Rosana Souza Rodrigues; Gustavo de Souza Portes Meirelles; Bruno Hochhegger. Extramedullary hematopoiesis: findings on computed tomography scans of the chest in 6 patients. J. bras. pneumol. vol.34 no.10 São Paulo Oct. 2008 (Link here)
2. Hassan M Yaish, MD. Thalassemia Intermedia. eMedicine here