title: Granulocytic Sarcoma in the Head and Neck: CT and MR Imaging Findings.
abstract: OBJECTIVE
  To evaluate characteristic computed tomography (CT) and magnetic resonance (MR) imaging findings of granulocytic sarcomas of the head and neck.
  
  
  METHODS
  The CT (n=11) and MR (n=1) images obtained from 11 patients (7 males and 4 females; mean age, 23.5 yr; age range, 1 to 69 yr) with histologically-proven granulocytic sarcomas of the head and neck were retrospectively reviewed. Histological confirmation was done by bone marrow biopsy in 9 patients, and/or local biopsy in 4 patients. The imaging findings were analyzed with particular attention to location, size, shape, margin, bone destruction, internal architecture, pattern and degree of enhancement, and multiplicity of the lesions.
  
  
  RESULTS
  The masses were most commonly located in the orbital cavity (n=8); other locations included lymph nodes (n=5) and palatine/pharyngeal/lingual tonsils (n=3). The mass sizes varied from a mean diameter of 1.3 to 5.8 cm (average, 2.6 cm). Multiple lesions were found in 6 patients. The shapes of the tumors were ovoid in 12 patients and irregular in 4 patients. Most lesions had poorly-defined margins (13/16) and invaded adjacent bony structures (5/16). On the pre-contrast CT images, the masses were iso- (5/8) or low-density (3/8) in comparison with muscle. The MRI, which was obtained in one patient in this study, showed that the mass was iso-signal intensity on T1-weighted images and iso-signal intensity on T2-weighted images compared to the gray matter of the brain. On the post-contrast CT images, there was homogenesous (n=12) or heterogeneous (n=4) enhancement, with mild (n=10), moderate (n=4), and marked (n=2) enhancement in the solid portions of the lesions.
  
  
  CONCLUSIONS
  Although rare, granulocytic sarcomas arise in various locations in the head and neck area (most commonly in the orbit) in the form of well-demarcated, and mildly- and homogenously-enhancing masses with adjacent bony invasion.
authors: Department of Radiology, College of Medicine, Inha University, Incheon, Korea.
authors: Bong Wan
authors: BW
authors: Noh
authors: Sun-Won
authors: SW
authors: Park
authors: Jung-Eun
authors: JE
authors: Chun
authors: Ji Hye
authors: JH
authors: Kim
authors: Hyung Jin
authors: HJ
authors: Kim
authors: Myung Kwan
authors: MK
authors: Lim