ABSTRACT
Keratoacanthoma of the skin and well-differentiated squamous cell carcinoma are two cutaneous neoplasms that most often occur in sun-exposed sites of light-skinned persons. It is often difficult to distinguish these two from each other either clinically or histologically. The view that these two cutaneous neoplasms are part of the same disease entity is not new. We reviewed 150 patients with these two diseases in an effort to see whether any specific criteria for diagnosis and treatment could be achieved. It is our hypothesis that they are not separate diseases but within the spectrum of the same disease. Keratoacanthoma may be some sort of aborted malignancy or hyperplastic premalignant lesion within the squamous cell carcinoma spectrum. The incidence of metastases from squamous cell carcinoma of the skin may be as high as 3%. We do not have the courage to wait 3 months to see if a potentially invasive and metastatic neoplasm is indeed involutional. Incision biopsy may be wrought with significant histopathological inconsistencies. We believe that early, complete excision is the treatment of choice for all skin neoplasms thought to be keratoacanthoma.