title: Testicular and epididymal appendages in the cynomolgus macaque (Macaca fascicularis).
abstract: BACKGROUND
  Vestigial remnants of the mesonephric duct and paramesonephric duct are well-known developmental abnormalities of the human testis and epididymis.
  
  
  RESULTS
  During routine macroscopic and histological examination of four cynomolgus macaques, three different forms of testicular and epididymal appendages were observed, namely a unilateral appendix testis, a bilateral appendix epididymidis, and several vasa aberrantia. By histological and immunohistochemical examinations it could be demonstrated that both the appendix testis and the appendix epididymidis consisted of a central fibromuscular core and a pseudostratified columnar epithelium at the outer surface. The vasa aberrantia were attached to the connective tissue sheaths of the epididymis/testis and were represented by small duct-like or cystic structures internally lined with a simple cuboidal to columnar, partly ciliated epithelium.
  
  
  CONCLUSIONS
  Awareness of these rudimental tissues in non-human primates is necessary to determine actual incidence rates in non-human primate species used in toxicological research and avoids misdiagnosing during routine necropsy and histological examinations.
authors.affiliation: Covance Laboratories GmbH, Department of Pathology, Münster, Germany. martina.zoeller@covance.com
authors.forename: M
authors.initials: M
authors.lastname: Zöller
authors.forename: S
authors.initials: S
authors.lastname: Friderichs-Gromoll
authors.forename: J
authors.initials: J
authors.lastname: Kaspareit
mesh_terms: D000818:Animals; D004822:Epididymis / Q000002:abnormalities*; D006801:Humans; D008252:Macaca fascicularis / Q000002:abnormalities*; D008297:Male; D013737:Testis / Q000002:abnormalities*