Testis and epididymis
Nonneoplastic testicular lesions
Anorchia / monorchidism / testicular regression

Author: Sean Williamson, M.D. (see Authors page)

Revised: 6 April 2017, last major update December 2012

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Anorchia [title] OR monorchidism [title] OR testicular regression [title]

Table of Contents
Definition / general
Cite this page: Anorchia / monorchidism / testicular regression. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/testisanorchia.html. Accessed October 16th, 2018.
Definition / general
  • Absence of one (monorchidism) or both testes
  • If phenotypically normal male and vas deferens is present, indicates a testicular regression syndrome caused by infection, trauma, torsion or prenatal hormone induced atrophy due to overproduction of androgens
  • A regressed testis is indicated by presence of a nodule of fibrosis, hemosiderin deposition, calcification or Leydig cells, in association with epididymis or proximal vas deferens
  • Presence of fat and connective tissue only does not rule out an intra-abdominal testis