Clinical misdiagnosis of squamous cell carcinoma in situ as seborrheic keratosis. A prospective study.
BACKGROUND
Seborrheic keratoses have on rare occasion been reported to undergo malignant transformation.


OBJECTIVE
Our purpose was to examine the incidence and distribution of squamous cell carcinomas (SCCs) in situ arising in clinically banal-appearing seborrheic keratoses.


METHODS
We prospectively selected such cases over a 6-month period of time from routinely accessioned specimens to a dermatopathology service.


RESULTS
We found 1.4% of clinically diagnosed seborrheic keratoses to be SCCs in situ. These lesions were more common in elderly persons and were more likely to occur on the head and neck, suggesting the role of cumulative sun damage in the transformation of such lesions.


CONCLUSIONS
Malignant transformation of seborrheic keratoses, although rare, appears to occur more frequently in the elderly on the head and neck. Because this change is not necessarily accompanied by clinically discernable changes, more careful scrutiny of such lesions may be of therapeutic rather than cosmetic significance in this population.
Department of Dermatology, University of Pennsylvania, Philadelphia.
J B
JB
Sloan
C
C
Jaworsky
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002278:Carcinoma in Situ / Q000175:diagnosis* / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000473:pathology; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D017492:Keratosis, Seborrheic / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000473:pathology