Keratoacanthoma Figure 1

Figure 1: Self resolving keratocanthoma in 2-year-old male rat.
Case history and photos.


Male hairless rat 2 years old. History of skin problems including small abscesses and cysts.

Clinical Signs

Growth on the rat’s left cheek began as a red bump that quickly enlarged to a hard raised black mass.


Initial diagnosis was a cornified cyst. Pathology revealed that the growth was actually a Keratoacanthoma.


The vet prescribed an antibiotic ointment to prevent infection and help soften the tissue.


The keratocanthoma eventually fell off leaving a small hole in the cheek that healed well. To date there have been no more incidents of KA.


Male hairless rat with keratoacanthoma on left cheek


Photos 1 and 2 showing a benign keratoacanthoma


Photo 3: Shows spontaneous healing.


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