Hematological neoplasms / lesions
Granulocytic sarcoma

Author: Hanni Gulwani, M.D. (see Authors page)

Revised: 20 June 2018, last major update December 2012

Copyright: (c) 2003-2018,, Inc.

PubMed Search: Granulocytic sarcoma mediastinum

Cite this page: Gulwani, H. Granulocytic sarcoma. website. Accessed July 19th, 2018.
  • Also called extramedullary myelogenous leukemia, chloroma
  • Usually 35 years old or younger or 65 years+
Clinical features
  • May be associated with myeloproliferative disease, acute myelogenous leukemia
  • Touch preps are helpful for diagnosis - show Auer rods with Romanowsky stain
Prognostic factors
  • Poor prognosis; usually evolves to acute myelogenous leukemia
Case reports
Gross description
  • Bulky anterior intrathoracic mass, green on cut section (hence "chloroma"), often centered in thymus
  • Fleshy, multilobated, poorly delineated, unencapsulated with hemorrhage and necrosis
  • May directly extend to thoracic structures
Microscopic (histologic) description
  • Sheets of large, monomorphic, polyhedral cells with irregular nuclear contours, vesicular chromatin, variable nucleoli
  • Mature and immature eosinophils
Electron microscopy description
  • Primary granules often present