Extramedullary hematopoiesis affects about 15% of the patients treated for thalassemia intermedia. Usually seen in adulthood, the most common location is the paraspinal region. Diagnosis and treatment of extramedullary hematopoiesis located in the pelvis of a young 15-year-old girl is discussed. The young age of the patient and the uncommon site of the mass first lead to the diagnosis of an ovarian dermoid cyst. Because of the clinical history and the typical feature on computed tomography scan, extramedullary hematopoiesis was concluded. A specific treatment based on blood transfusion and hydroxyurea was first proposed but remained inefficient. Surgical excision was thus successfully performed. Whereas surgery is limited to spinal cord compression in paraspinal extramedullary hematopoiesis, this observation argues for surgical treatment in symptomatic intraabdominal extramedullary hematopoiesis when medical treatment fails.