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Testis & paratestis

Nonneoplastic lesions

Orchitis

Author: Sean R. Williamson, M.D.

Last author update: 1 December 2012

Last staff update: 18 July 2023

Copyright: 2002-2023, PathologyOutlines.com, Inc.

PubMed Search: Orchitis testis

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Cite this page: Williamson S. Orchitis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/testisorchitis.html. Accessed October 2nd, 2023.

AIDS

Associated with markedly reduced spermatogenesis, arrested maturation, germ cell aplasia, tubular hyalinization / thickening of basement membranes, interstitial inflammation and fibrosis, reduction in Leydig cells, Sertoli cell only pattern (J Pathol 1991;163:47, Urology 1999;53:203, Mod Pathol 1989;2:233, Hum Pathol 1989;20:210)
Often other infections in testis or epididymis (Candida, CMV, Histoplasma, mycobacteria, toxoplasmosis)
Testicular atrophy related findings do not appear to be immune mediated (Hum Pathol 1989;20:572)
Testis is an uncommon location for Kaposi sarcoma in AIDS patients

Brucellosis

Zoonotic infection acquired from sheep, camels, cattle, dogs, goats, reindeer, swine via skin / mucous membrane contact or contaminated animal products
Affects testis and epididymis (epididymo-orchitis) in 2 - 20% of cases, causing scrotal pain, swelling, fever
Often diagnosed by laboratory studies
Case report: 32 year old man with painless testicular mass-brucellosis (Int J Urol 2004;11:683)
Micro description: granulomatous or testicular abscess
Treatment: antibiotics; orchiectomy if resembles a neoplasm or refractory to therapy
Additional references: Urol Int 2009;82:158, BMC Res Notes 2011;4:286, Clin Infect Dis 2001;33:2017

Gonorrhea

Usually spreads from posterior urethra to prostate, seminal vesicles and epididymis
Testis involved only if untreated

Granulomatous orchitis

Rare; usually men 40 - 59 years with sudden onset of tender testicular mass, variable fever
May be a response to acid fast products of disintegrated sperm, postinfectious or due to trauma or sarcoidosis
Resembles pyogenic epididymo-orchitis
Benign, although granulomatous inflammation may be associated with seminoma
Recommend cultures to rule out infectious process (brucellosis, leprosy, sarcoidosis, syphilis, TB)
Granulomatous ischemic lesion
- Usually affects head of epididymis
- May be due to ischemia with secondary granulomatous reaction and scarring
Gross description
- Solid, unilateral nodular enlargement of testis; resembles lymphoma
Microscopic (histologic) description
- Lymphocytes and plasma cells infiltrate interstitium and surround seminiferous tubules
- Giant cells and histiocytes that resemble (but are not) actual granulomas
- Granulomatous ischemic lesion
  - Zone of necrosis involving efferent ducts and interstitial connective tissue, with adjacent lymphocytes and macrophages
  - Macrophages form large clusters with cholesterol crystals and foreign body type giant cells in duct lumen
  - Also intratubular epithelial regeneration and proliferation of small ducts showing epithelial regeneration and numerous spermatozoa in their lumen
  - Associated with ceroid granuloma, spermatic granuloma and epidermoid metaplasia of the efferent ducts

Reference: Am J Surg Pathol 1997;21:951

Histoplasma capsulatum

Rarely presents as testicular mass
May resemble sperm granuloma (J Clin Pathol 1974;27:929)
Caseating granulomatous inflammation with giant cells
Small yeast forms (2 - 5 micrometers) are identifiable by silver stain (J Urol 2000;164:1652)

Leprosy

Does not occur in U.S.
Rarely presents with orchitis (Am J Clin Pathol 1980;73:712)
Testicular involvement thought to be facilitated by lower temperature of scrotum
3 phases of testicular involvement:
1. Vascular phase: blood vessels show perivascular lymphocytic inflammation and interstitium is filled with macrophages containing mycobacteria
2. Interstitial phase: endarteritis, Leydig cell clusters, interstitial fibrosis, histiocytes containing acid fast bacteria and reduced spermatogenesis
3. Obliterative phase: dense fibrosis, no detectable tubules, reduced vessels, rare acid fast bacteria; associated with gynecomastia and infertility

Mumps

Testicular infections rare in infected children (prepubertal) but occur in 15 - 40% of postpubertal men one week after parotiditis
Usually unilateral (bilateral in 15 - 30%); epididymitis is also common (85%) and often precedes orchitis
One - third of infected postpubertal men develop testicular atrophy, 2 - 10% become infertile
Incidence increasing, due to reduced use of vaccine (BJU Int 2010;105:1060)

Pyogenic epididymo-orchitis

Usually due to E. coli
Resembles granulomatous orchitis
Complications: venous thrombosis, septic testicular infarct

Syphilis

Testis usually involved first
Discrete gummas contribute to enlarged, irregular testis
Gummas: diffuse interstitial inflammation with edema, lymphocytes and plasma cells, with obliterative endarteritis and perivascular cuffing
Spirochetes usually identified in gummatous but not fibromatous stages

Tuberculosis