E2555. Far From the Marrow: A Primer on Extramedullary Hematopoiesis
  1. Gerardo Torres; University of Puerto Rico
  2. Valerie Vargas; University of Puerto Rico
  3. Maria Tonkopiy; San Juan Bautista School of Medicine
  4. Sylvia Eliza; University of Puerto Rico
  5. Eugenio Marcano; University of Puerto Rico
Extramedullary hematopoiesis (EMH) is the production of blood cell lineage outside the bone marrow. Tissues commonly involved include the liver, spleen, lymph nodes, and, less frequently, within the central nervous system (CNS). EMH is an incidental finding in patients with myeloproliferative diseases, anemias, and other hematologic conditions. Imaging of patients with preexisting hematologic conditions warrants knowledge and accurate identification of possible EMH findings as most masses produced by EMH do not typically cause symptoms. However, EMH masses within the CNS may present with neurologic symptoms secondary to mass effect upon nearby structures. Image-based diagnosis is crucial in preventing invasive biopsy with high risk of complications. The purpose of this educational exhibit is to properly identify and confidently diagnose extramedullary hematopoiesis to avoid unnecessary additional imaging/interventions and help guide adequate management.

Educational Goals / Teaching Points
Review normal hematopoiesis and discuss the causes and pathophysiology of extramedullary hematopoiesis. List common (and uncommon) sites where extramedullary hematopoiesis may occur. Describe radiological findings and show case examples of extramedullary hematopoiesis.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
In this educational exhibit we will discuss normal physiologic hematopoiesis as well as abnormal pathological hematopoiesis in the setting of systemic disease. Using different imaging modalities including CT, MRI, and PET, we will demonstrate the imaging characteristics of extramedullary hematopoiesis in common and uncommon locations including intracranial and intrathoracic, among others.

This educational exhibit showcases extramedullary hematopoiesis, its pathophysiology and possible locations throughout the body. We present key imaging findings as well as teach important patient medical history and presentation for better identification and diagnosis of extramedullary hematopoiesis. After viewing our educational exhibit, the reader should be able to efficiently recognize and include extramedullary hematopoiesis as a differential diagnosis in the appropriate clinical setting.