Causative factors involved in the pathogenity of the keratoacanthoma are solar radiation, X and PUVA rays, chemical carcinogens, trauma, smoking, genetic factors, infectious and immunological (immunosuppression) factors.
The typical course of a keratoacanthoma is characterized by the rapid growth phase (1-2 months), the stage of tranquility where the development of the severe damage stops (1-2 months) and the stage of spontaneous regression during which the damage gradually reduces in size (2-7 months). One out of five cases does not follow the aforementioned growth pattern. The damage may continue increasing in size; it may also develop an aggressive attitude as an invasive squamous cell carcinoma.
So the reasonable question is: what is the necessity of treatment if there is a spontaneous regression? Therapeutic intervention is necessary for many reasons. Firstly, the aesthetic result after the treatment is more acceptable than the deformed scar of the spontaneous regression. Secondly, the surgical operation of the removal is combined with tissue histological examination for the confirmation of the diagnosis. Thirdly, since the aggressiveness of the lesion cannot be foreseen, treatment speeds up the healing, decreases the time that it remains as an abnormal damage and prevents any destruction of important structures of the face. Fourthly, without treatment, close, long-term observation is required, without being able to rule out the possibility of a malignant change or a metastasis.
Total surgical removal is the usual way of treatment. This method provides suitable material for biopsy and offers a definitive treatment with a good aesthetic result. With the appropriate diagnostic and therapeutic approach an excellent prediction is ensured.