ABSTRACT
Extramedullary hematopoiesis is an important side effect of intermediate thalassemia. It is usually observed in paravertebral and other soft tissues as a compressive mass and rarely in intracranial, but it has not been roported in sphenoidal sinus in literature until now. In this article a 21-year old patient with intermediate thalassemia and sphenoidal mass has been reported. The patient underwent splenectomy and cholecystectomy simultaneously, for the billiary stones. After splenectomy his erythroblast increasesd progressively in peripheral blood, and one year later he was treated, because of acute sinusitis. Imaging studies and biopsy revealed the hematopoietic mass in sphenoidal sinus. The patient did not respond to surgical and medical treatments; therefore, he was referred for the hcmatopoietic stem cell transplantation. Ectopic hematopoiesis is a rare event in thalassemia, but it can appear in such important areas such as paravertebral and intracranial, which causes severe side effects. Therefore, immediate diagnosis and treatment in high risk patients can prevent these effects