title: Imaging features of primary and metastatic alveolar soft part sarcoma: single institute experience in 25 patients.
abstract: OBJECTIVE
  To describe imaging features of primary and metastatic alveolar soft part sarcoma (ASPS).
  
  
  METHODS
  In this institutional review board-approved and Health Insurance Portability and Accountability Act-compliant retrospective study, 25 patients (14 males; mean age, 25 years; range, 18-40 years) with pathologically proven ASPS seen at our institute between 1995 and 2013 were included. Imaging of primary tumours in 5 patients and follow-up imaging in 25 patients were reviewed by 2 radiologists in consensus. Clinical information was obtained from electronic medical records.
  
  
  RESULTS
  The most common sites for the primary tumour were extremities (17/25, 68%) and torso (6/25, 24%). Primary tumours (n = 5) were well circumscribed, compared with skeletal muscle, were isodense on CT, hyperintense on T1 and T2 weighted images with intense post-contrast enhancement, prominent feeders on CT and flow voids on MRI. Metastases developed in 23/25 (92%) patients, 18 at presentation. The most common sites of metastases were the lungs (100%), lymph nodes (74%), bones (57%) and brain (43%). Visceral and nodal metastases were hypervascular. At the time of reporting the results, 15 patients have died, 6 are alive and 4 were lost to follow-up. Median survival was 74 months for those without brain metastases (n = 8) and 60 months for those with brain metastases (n = 7). Median survival was shorter for patients with metastases at presentation.
  
  
  CONCLUSIONS
  ASPS most commonly involves the lower extremities of young adults, is hypervascular on imaging, often metastasizes at presentation, frequently to lung, nodes, bones and brain, and has an indolent course despite metastases. Brain metastases and high tumour burden (number of metastatic sites) at presentation decreased survival in our study.
  
  
  CONCLUSIONS
  ASPS has an unusual pattern of metastases to the brain and nodes in addition to lung and bones. It has an indolent course despite metastases.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: S
authors.initials: S
authors.lastname: Sood
authors.forename: A D
authors.initials: AD
authors.lastname: Baheti
authors.forename: A B
authors.initials: AB
authors.lastname: Shinagare
authors.forename: J P
authors.initials: JP
authors.lastname: Jagannathan
authors.forename: J L
authors.initials: JL
authors.lastname: Hornick
authors.forename: N H
authors.initials: NH
authors.lastname: Ramaiya
authors.forename: S H
authors.initials: SH
authors.lastname: Tirumani
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000175:diagnosis / Q000556:secondary; D001932:Brain Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000401:mortality / Q000556:secondary; D003131:Combined Modality Therapy; D003952:Diagnostic Imaging; D005121:Extremities; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis / Q000556:secondary; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000556:secondary; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D018234:Sarcoma, Alveolar Soft Part / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000556:secondary / Q000601:surgery; D014057:Tomography, X-Ray Computed; D014481:United States; D055815:Young Adult