Fine needle aspiration of thoracic extramedullary hematopoiesis

Thoracic manifestations of extramedullary hematopoiesis (EMH) are well known clinically, radiologically and pathologically; it is generally confirmed histologically by open biopsy or postmortem examination. We report a case of EMH diagnosed by percutaneous fine needle aspiration (FNA) in a patient with long-standing, acquired, sideroblastic anemia. The aspirate was very cellular and composed of normal bone marrow elements with an erythroid to myeloid cell ratio of 3 to 1. Megakaryocytes were abundant but constituted less than 1% of the total cell population. This case illustrates that the diagnosis of EMH is possible by FNA and that thoracotomy for diagnostic purposes can be circumvented.