title: Histology in mixed germ cell tumors. Is there a favorite pairing?
abstract: OBJECTIVE
  Mixed germ cell tumors account for approximately 30% to 50% of testicular tumors. To our knowledge a systematic review with statistical analysis of the associations of histological subtypes in mixed germ cell tumors has not been done previously. It was our impression that such associations exist. Delineating concordant histological types may provide insight into the ontogeny of testicular tumors and also have important clinical implications.
  
  
  METHODS
  We retrospectively reviewed the testis cancer data base at our institution. The primary tumor of orchiectomy specimens was examined in 2589 patients. Of these patients mixed histology was noted in 1765 (68.2%). ORs were calculated for all possible combinations of teratoma, embryonal carcinoma, yolk sac tumor, choriocarcinoma and seminoma. In addition, we evaluated the association of various histological types with teratoma at post-chemotherapy retroperitoneal lymph node dissection.
  
  
  RESULTS
  Of 10 possible combinations of histological types in the primary tumor, positive correlations were noted in 4. The strongest correlation was found between teratoma and yolk sac tumor (OR 2.58, p <0.001). Teratoma or yolk sac tumor in the testis was associated with teratoma in the pathology specimen at post-chemotherapy retroperitoneal lymph node dissection.
  
  
  CONCLUSIONS
  The strongest associations of histological subtypes in mixed germ cell tumors were seen between yolk sac tumor and teratoma. Similar associations are seen in late relapse and in some cases of prepubertal tumors. Further study of these associations may prove valuable in understanding the biology and clinical behavior of germ cell tumors.
authors.affiliation: Department of Urology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Ashraf A
authors.initials: AA
authors.lastname: Mosharafa
authors.forename: Richard S
authors.initials: RS
authors.lastname: Foster
authors.forename: Bradley C
authors.initials: BC
authors.lastname: Leibovich
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Ulbright
authors.forename: Richard
authors.initials: R
authors.lastname: Bihrle
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Einhorn
authors.forename: John P
authors.initials: JP
authors.lastname: Donohue
mesh_terms: D018237:Germinoma / Q000473:pathology*; D006801:Humans; D008297:Male; D009378:Neoplasms, Multiple Primary / Q000473:pathology*; D012189:Retrospective Studies; D013736:Testicular Neoplasms / Q000473:pathology*