Equis ISSN 2398-2977

Penis: squamous cell carcinoma

Synonym(s): Penile tumor

Contributor(s): Prof Derek Knottenbelt, Joyce Parlevliet, Anna Hollis

Introduction

  • Squamous papillomas, squamous cell carcinomas, melanomas and sarcoids are the most common tumors of the penis Penis: neoplasia seen in the horse.
  • The penile tumor is mostly seen in geldings and is more common in the aged gelding.
  • Benign and malignant forms occur. The former are more common in older geldings while the latter is more common in geldings under 12-13 years of age.
  • Cause: precarcinomatous changes caused by smegma. 
  • Signs: clinically two forms can be recognized:
    • Proliferative lesion.
    • Ulcerative/destructive lesion.  
  • Mixed forms may also occur.
  • The early precancerous stage can often be recognized, particularly in geldings with non-pigmented penile skin.  
  • Spread to involve or primary involvement of the preputial skin is a serious sign that is usually accompanied by high malignancy, both locally and systemically.
  • Malignant forms may metastasize to local lymph nodes (inguinal/iliac) or to organs remote from these, however enlargement of lymph nodes because of may be also a result of secondary infections.
  • Metastasis to lumbar vertebral bodies, lungs, liver and spleen have been reported.
  • Diagnosis: examination of sheath/penis/prepuce, biopsy, rectal examination, bacteriology. 
  • Treatmentregular washing, surgical extirpation of affected skin/penile amputation, cryonecrosis of focal lesions, reefing of preputial reflection, resection of circumferential segment of internal preputial lamina or phallectomy.
  • Prognosis: guarded.
Print off the Owner factsheet on Cancer in horses to give to your clients.

Pathogenesis

Etiology

  • Precarcinomatous changes caused by smegma. 
  • Continued contact with smegma on the non-pigmented skin are suggested as the combined circumstances that predispose to the condition.
  • It is not known which component of smegma is the most likely material.

Predisposing factors

General

  • Age and gelding status are the most important predisposing factors.
  • Non-pigmented preputial skin.

Timecourse

  • Usually slow development of lesions for precarcinomatous stages.

Diagnosis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Prevention

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • van den Top J G B, Ensink J M & Barneveld A (2011) Penile and preputial squamous cell carcinoma in the horse and proposal of a classification system. Equine Vet Educ 23 (12), 636-648 VetMedResource.
  • van den Top J G B, de Heer N, Klein W R & Ensink J M (2008) Penile and preputial tumours in the horse: A retrospective study of 114 affected horses. Equine Vet J 40 (6), 528-532 PubMed.
  • van den Top J G B, de Heer N, Klein W R & Ensink J M (2008) Penile and preputial squamous cell carcinoma in the horse: A retrospective study of treatment of 77 affected horses. Equine Vet J 40 (6), 533-537 PubMed.
  • May K A, Kuebelbeck K L & Johnson C M (2008) Urinary bladder rupture secondary to penile and preputial squamous cell carcinoma in a gelding. Equine Vet Educ 20 (3), 135-139 VetMedResource.
  • Mair T S (2004) Management of squamous cell carcinoma of the penis. Equine Vet Educ 16 (1), 18-19 VetMedResource.
  • Archer D C & Edwards G B (2004) En bloc resection of the penis in five geldings. Equine Vet Educ 16 (1), 12-19 VetMedResource.
  • Stephenson R (2003) Management of squamous cell carcinoma of the penis in an aged pony. Vet Rec 152, 333-334.
  • Paterson S (1997) Treatment of superficial ulcerative squamous cell carcinoma in three horses with topical 5-fluorouracil. Vet Rec 141, 626-628 PubMed.
  • Harrison L D & May. Penile carcinoma with secondary metastasis to the lumbar vertebrae. Vet Rec.
  • Noack P (1956) Die Geschwülste der oberen Atmungswege bei den Haussäugetieren (Teile I, II). Wiss Z. Humboldt-Univ 6, 293-314 & 373-391.

Other sources of information

  • Pascoe R R & Knottenbelt D (1999) Neoplastic conditions. In: Manual of Equine Dermatology. W B Saunders, UK. pp 244-252.
  • Mckinnon A O & Voss J L (1993) Equine Reproduction. Lea & Febiger, USA.


ADDED