Macroscopic hematuria in patient with myelofibrosis caused by extramedullary hematopoiesis of bladder.

Extramedullary hematopoiesis (EMH) is a physiologic process in fetal life. However, after birth, its occurrence is abnormal, and it develops when hematopoiesis in the bone marrow is disturbed, such as occurs in many hematologic disorders. EMH can become symptomatic, depending on its extent and location. We describe the case of a 67-year-old man with postpolycythemic myelofibrosis who presented clinically with macroscopic hematuria due to EMH in the bladder. EMH in the bladder is extremely rare but illustrates the importance of an adequate pathologic assessment of transurethral resection chips, especially in patients with underlying disease.