[A case of surgically resected mediastinal mass histologically proven to be a mass-like tissue presenting extramedullary hematopoiesis accompanied by thalassemia].

We experienced with a case showing a mediastinal mass on chest X-ray accompanied by thalassemia. Preoperative diagnosis for this mass was a neulogenic tumor based on the findings of roentgenogram. Surgical resection of the mass was performed, and histology revealed that it was a mass-like tissue presenting extramedullary hematopoiesis. Generally speaking, any tissues functioning as extramedullary hematopoiesis should not be resected in patients with anemia or showing bone marrow suppression. And it is also said that 111In-chloride scintigram is highly diagnostic for patients with a tissue functioning as extramedullary hematopoiesis. We had not performed 111In-chloride scintigram for this case preoperatively and performed a resection of the mediastinal mass carelessly. Care should be taken not to perform surgical resection carelessly in cases with a mediastinal mass accompanied by anemia or bone marrow suppression.