title: MRI features of skeletal muscle lymphoma.
abstract: OBJECTIVE
  The purpose of this study was to assess the MRI findings of skeletal muscle lymphoma.
  
  
  METHODS
  MR images of pathologically proven lymphoma of skeletal muscle in 20 patients were retrospectively reviewed for the presence or absence of individual imaging findings. Nine patients had primary muscle lymphoma, and 11 patients had muscle metastasis from systemic lymphoma.
  
  
  RESULTS
  The initial manifestation of skeletal muscle lymphoma was a muscle mass in 15 patients (75%) and abnormal muscle signal intensity in five patients (25%). Muscle enlargement was found in all cases. Long segmental involvement with orientation of the tumor along muscle fascicles was found in 15 patients (75%). Seventeen patients (85%) had traversing vessels within involved muscles. All of the tumors had equal to slightly increased signal intensity compared with normal muscle on T1-weighted images and intermediate signal intensity compared with fat on T2-weighted images. Among the 19 patients who underwent contrast-enhanced imaging, skeletal muscle lymphoma exhibited diffuse homogeneous enhancement in 13 patients (68%), predominantly peripheral thick bandlike enhancement in four patients (21%), and marginal septal enhancement in two patients (11%). Thick irregular enhancement of both deep and superficial fascia was found in 16 patients (84%), and one patient (5%) had deep enhancement only. Subcutaneous stranding was found in 16 patients (80%) and skin thickening in four patients (20%).
  
  
  CONCLUSIONS
  Skeletal muscle lymphoma has distinctive MRI features that help differentiate it from other soft-tissue tumors and tumorlike lesions.
authors.affiliation: Department of Radiology, Seoul St. Mary's Hospital School of Medicine, The Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-701, South Korea.
authors.forename: Chang Woo
authors.initials: CW
authors.lastname: Chun
authors.forename: Won-Hee
authors.initials: WH
authors.lastname: Jee
authors.forename: Hye Jung
authors.initials: HJ
authors.lastname: Park
authors.forename: Yeo Joo
authors.initials: YJ
authors.lastname: Kim
authors.forename: Jeong-Mi
authors.initials: JM
authors.lastname: Park
authors.forename: Sang-Hoon
authors.initials: SH
authors.lastname: Lee
authors.forename: Sung-Hwan
authors.initials: SH
authors.lastname: Park
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008223:Lymphoma / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019042:Muscle Neoplasms / Q000473:pathology* / Q000556:secondary; D018482:Muscle, Skeletal / Q000473:pathology*; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA