Basal Cell Carcinoma

A low-grade malignant proliferation of epidermal cells that recapitulates the basal cell layer of the normal epidermis or the adnexa. These neoplasms show no differentiation to any of the adnexal structures and may have epidermal contiguity which may be multifocal.

Histology:

Clear Cell
•Clear-cell type is uncommon.
•Architecture is that of a solid basal cell carcinoma
•Cells are large and polygonal
•Cells have a clear or finely granular cytoplasm
•Nuclei are ovoid and uniform, nucleoli small
•Number of mitosis found may be quite variable.

Infiltrative
•May have an association with the overlying epidermis
•Cords of primitive basaloid cells extend into the dermis and occasionally the subcutis
•Tumor cells have small, hyperchromatic nuclei with scant cytoplasm
•Mitotic figures may be numerous
•Often an extensive proliferation of stromal fibroblasts
•Tumor shows no adnexal differentiation which allows it to be differentiated from sebaceous epithelioma and infiltrative and malignant trichoepithelioma

Prognosis:
•Good following wide excision, may recur but metastasis not reported

Breeds at Increased Risk
Breed	Odds Ratio	95% Confidence Limit	Probability
Ragdoll	9.0	1.21 - 66.33	0.009

Sex Distribution (N=184)

Sex Status
Percent

Male
(46.4%)

43.5%

intact
(13.9%)

12.0

neutered
(32.5%)

31.5

Female
(53.6%)

56.5%

intact
(18.4%)

21.7

neutered
(35.2%)

34.8

(normal sex distribution)

Anatomic Location (N=174)

Site
Percent

Head 23.6

Neck 20.7

Forelimb 15.5

Hindlimb 14.9

Abdomen 8.6

Thorax 6.9

Back 3.4

Multiple 2.9

Tail 2.3

Perineum 1.2