title: Primary thyroid lymphoma: CT findings.
abstract: BACKGROUND
  To evaluate the computed tomographic (CT) findings of primary thyroid lymphoma.
  
  
  METHODS
  The clinicopathological data and CT images of nine patients with primary thyroid lymphoma were retrospectively reviewed. The CT appearances were classified into three types: type 1, a solitary nodule surrounded by normal thyroid tissue; type 2, multiple nodules in the thyroid, and type 3, a homogeneously enlarged both thyroid glands with a reduced attenuation with or without peripheral thin hyperattenuating thyroid tissue.
  
  
  RESULTS
  All patients had a rapidly enlarging thyroid mass and coexistent Hashimoto's thyroiditis. One patient showed type 1 pattern, three type 2, and five type 3. Six patients had homogeneous tumor isoattenuating to surrounding muscles. The tumors had a strong tendency to compress normal remnant thyroid and the surrounding structure without invasion.
  
  
  CONCLUSIONS
  Primary thyroid lymphoma should be included in the differential diagnosis when old female had a homogeneous thyroidal mass isoattenuating to muscles, which does not invade surrounding structures.
authors.affiliation: Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Clinical Research Institute, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul 110-744, South Korea.
authors.forename: Hyo-Cheol
authors.initials: HC
authors.lastname: Kim
authors.forename: Moon Hee
authors.initials: MH
authors.lastname: Han
authors.forename: Keon Ha
authors.initials: KH
authors.lastname: Kim
authors.forename: Hwan Jun
authors.initials: HJ
authors.lastname: Jae
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Lee
authors.forename: Sam Soo
authors.initials: SS
authors.lastname: Kim
authors.forename: Kwang Hyun
authors.initials: KH
authors.lastname: Kim
authors.forename: Kee-Hyun
authors.initials: KH
authors.lastname: Chang
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D016393:Lymphoma, B-Cell / Q000150:complications / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000150:complications / Q000000981:diagnostic imaging*; D013967:Thyroiditis, Autoimmune / Q000150:complications; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography