Abnormal imaging presentations of extramedullary hematopoiesis in a 21-year old and 72-year old female.

Extramedullary hematopoiesis (EH) refers to hemopoiesis that occurs outside of the bone marrow and can be physiologic or pathologic in nature. Common sites of EH include the liver, spleen, and paravertebral soft tissues. Less commonly, EH can occur in the kidneys, pleura, paranasal sinuses, and various other organs. In this report, we describe two cases of EH with abnormal presentations on imaging. The first case discusses a 72-year-old female with a history of chronic myelogenous leukemia complicated by myelofibrosis. Outpatient computed tomography (CT) of the abdomen and pelvis obtained for symptoms of hematuria demonstrated infiltration of the pericalyceal system by ill-defined soft tissue attenuating material. A well-circumscribed hypoattenuating splenic mass and enlarged retroperitoneal lymph nodes were also identified. CT-guided biopsy of an enlarged left para-aortic lymph node was ultimately performed which demonstrated abundant EH. The second case involves a 21-year-old female with a history of sickle cell anemia who originally presented to the emergency department with worsening chest and back pain. A CT of the abdomen was ultimately obtained which revealed multiple hypoattenuating splenic masses, a focal hypoattenuating liver lesion, mild hepatomegaly, and prominent retroperitoneal lymph nodes. Subsequent MRI revealed innumerable well-circumscribed intrahepatic lesions that were not readily apparent on the previous CT which demonstrated increased signal intensity on T1- and T2-weighted images. Ultrasound-guided biopsy of one of the splenic masses was ultimately performed, which revealed abundant EH.