Intrathoracic extramedullary hematopoiesis mimicking intrathoracic tumors: A case report

Abstract

Extramedullary hematopoiesis (EMH) is a rare disease that is characterized by the presence of hemopoietic tissue outside the bone marrow. The masses that form are usually microscopic and asymptomatic, but occasionally lead to tumor-like masses. A 56-year-old male who initially presented to the First Affiliated Hospital, School of Medicine, Zhejiang University (Hangzhou, China) with upper abdominal pain and jaundice was found to have paravertebral masses in the thorax. Histopathological examination of a computed tomography-guided needle aspiration biopsy of the masses revealed EMH. The current study presents this unusual case, in which EMH was diagnosed by chance in a patient with hereditary spherocytosis. As the intrathoracic EMH was asymptomatic, the patient was discharged with the proviso of regular follow-up examinations. The patient exhibited improved blood cell counts following a splenectomy to reduce the hemolysis and stabilize the thoracic masses. The thoracic masses have been closely followed for one and a half years. A correct diagnosis can thus aid in avoiding unnecessary surgical intervention, particularly in an asymptomatic patient.

Keywords: extramedullary hematopoiesis; hemolytic anemia; hereditary spherocytosis; tumor-like masses.

Figure 1

Unenhanced thoracic computed tomography (CT) scan showing (A) multiple well-marginated bilateral solid masses, without calcification, located at the paravertebral region, and (B) lesions showing uneven enhancement during the arterial phase. The necks of the ribs were extremely thin.

Figure 2

Microscopic examination of a biopsy showing extensive extramedullary hemopoiesis (EMH) with strong erythroid hyperplasia (stain, hematoxylin and eosin; magnification, ×400).