title: Pyothorax-associated lymphoma: imaging findings.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the radiologic features of pyothorax-associated lymphoma on CT scans and chest radiographs.
  
  
  METHODS
  Radiographs and CT scans of 21 patients with biopsy-proven pyothorax-associated lymphoma (17 men, four women; median age, 71 years; range 52-77 years) were retrospectively identified. Two readers in consensus analyzed the morphologic imaging features of pyothorax-associated lymphoma and determined their relation to the preexisting chronic empyema cavity. In 13 cases, gallium scans were available and were reviewed.
  
  
  RESULTS
  Sixteen patients had a history of artificial pneumothorax therapy for tuberculosis. Pyothorax-associated lymphoma was visualized mainly (71.4% of cases) as extrapulmonary pleural masses on chest radiographs. The CT features included a lenticular (60%) or crescentic (20%) soft-tissue mass located eccentrically at the margin of a coexistent empyema cavity, which was present in all cases. Masses of pyothorax-associated lymphoma were commonly located in the lateral costal pleura (50%) or at the costophrenic angle (30%). The tumor matrix often appeared heterogeneous and contained areas of necrosis (60%). Direct invasion of the chest wall, ribs, lung parenchyma, and abdomen was found in 75%, 50%, 25%, and 25% of patients. Gallium scans, when available, showed marked uptake in 10 of 13 patients (76.9%).
  
  
  CONCLUSIONS
  In patients who have undergone artificial pneumothorax therapy for tuberculosis more than 20 years in the past, a pleural soft-tissue mass adjacent to the margin of a coexistent empyema cavity suggests the presence of pyothorax-associated lymphoma. Knowledge of the typical radiologic findings and locations of pyothorax-associated lymphoma help in the diagnosis of this rare pathologic entity.
authors.affiliation: Department of Radiology, Stanford University School of Medicine, 300 Pasteur Dr., Rm. S-072, Stanford, CA 94305, USA. takueda-rad@umin.ac.jp
authors.forename: Takuya
authors.initials: T
authors.lastname: Ueda
authors.forename: Christe
authors.initials: C
authors.lastname: Andreas
authors.forename: Jun
authors.initials: J
authors.lastname: Itami
authors.forename: Kunihisa
authors.initials: K
authors.lastname: Miyakawa
authors.forename: Hajime
authors.initials: H
authors.lastname: Fujimoto
authors.forename: Hisao
authors.initials: H
authors.lastname: Ito
authors.forename: Justus E
authors.initials: JE
authors.lastname: Roos
mesh_terms: D000368:Aged; D001706:Biopsy; D003937:Diagnosis, Differential; D004654:Empyema, Tuberculous / Q000150:complications* / Q000000981:diagnostic imaging; D005260:Female; D005710:Gallium Radioisotopes; D006801:Humans; D007564:Japan; D008223:Lymphoma / Q000000981:diagnostic imaging* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011031:Pneumothorax, Artificial / Q000009:adverse effects*; D013902:Radiography, Thoracic; D012189:Retrospective Studies; D014055:Tomography, Emission-Computed; D014057:Tomography, X-Ray Computed; D014396:Tuberculosis, Pleural / Q000150:complications; D051598:Whole Body Imaging
chemical_list: D005710:Gallium Radioisotopes