Basosquamous Carcinoma

Supported by the Savannah and Barry French Poodle Memorial Fund
University of Pennsylvania School of Veterinary Medicine
Last Modified: August 21, 2005

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Michael H. Goldschmidt, MSc, BVMS, MRCVS, Diplomate ACVP Professor and Head, Laboratory of Pathology and Toxicology Chief, Surgical Pathology Department of Pathobiology
Frances S. Shofer, PhD, Adjunct Associate Professor of Epidemiology and Biostatistics

Definition: A low-grade malignancy composed of basal cells with foci of squamous or follicular infundibular differentiation.


Sex N Percent
Female 81 20% (21%)
Female Spayed 161 39% (33%)
Male 92 23% (25%)
Male Castrated 74 18% (21%)
(Normal Population %)  

Breeds at
Increased Risk
N Probability OR 95%
Confidence Interval
Saint Bernard 6 0.0003 6.9 3.1 15.5
Old English Sheepdog 6 0.0157 3.1 1.4 6.9
Samoyed 5 0.0456 2.6 1.1 6.3
Scottish Terrier 7 0.0305 2.4 1.1 5.1
Golden Retriever 62 <0.0001 2.3 1.8 3.0
English Springer Spaniel 14 0.0080 2.2 1.3 3.7
Cocker Spaniel 27 0.0405 1.5 1.0 2.2

Breeds at
Decreased Risk
N Probability OR 95%
Confidence Interval
Boxer 4 0.0168 0.3 0.1 0.9
Rottweiler 2 0.0109 0.2 0.1 0.9

Site Percent
Head 24.3%
Hindlimb 17.2%
Forelimb 13.0%
Neck 11.4%
Back 9.8%
Thorax 9.8%
Abdomen 8.7%
Tail 2.4%
Multiple Sites 2.1%
Perineum 1.3%

OncoLink Veterinary Cancers

Clinical Presentation/Physical Exam Findings

  • an exophytic (growing outward from the skin) growth, freely movable over the subcutaneous tissue
  • seen less often on the head and neck than trichoblastomas
  • more are seen on other body sites

Tumor Pathology

Gross Findings

  • extensions into the deep dermis and subcutaneous tissue
  • cut surface of the tumor may be white or pigmented

Microscopic Findings

  • multilobulated mass occupies and infiltrates the dermis 
  • may have association with the epidermis
  • at the periphery of the lobules are the basaloid cells
  • in the center of the lobules, cells show abrupt keratinization
  • keratinized cells display atypia
  • numerous mitotic figures may be observed
  • melanin may be present in the peripheral basaloid cells

Clinical Behavior

Basosquamous carcinomas may recur at the site of excision. Metastasis has not been reported with basosquamous carcinomas.


  • Goldschmidt, M.H., & Hendrick, M.J. (2002). Tumors of the skin and soft tissue. In D.J. Meuten (Ed.), Tumors in domestic animals 4 th ed (pp. 45-119). Iowa: Iowa State Press
  • Goldschmidt, M.H., & Shofer, F.S. (1998). Skin tumors of the dog and cat. Woburn, MA: Butterworth-Heinemann
  • Gross, T.L., Ihrke, P.J., & Walder, E.J. (1992). Veterinary dermatopathology: A macroscopic and microscopic evaluation of canine and feline skin disease. (pp. 327-485). St. Louis, Missouri: Mosby Year Book
  • World Health Organization (1998). Histological classification of epithelial and melanocytic tumors of the skin of domestic animals (2 nd series, vol 3). Washington, DC: Armed Forces Institute of Pathology
  • Yager, J.A. & Wilcock, B.P. (1994). Color atlas and text of surgical pathology of the dog and cat. Ontario, Canada: Mosby Year Book


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