Proliferative actinic keratosis.
BACKGROUND
Solar/actinic keratoses (AKS) are premalignant lesions, usually less than 1 cm in diameter, that appear on chronically sun-damaged skin.


METHODS
We describe four patients with a form of AK that enlarged and recurred despite standard treatment. Histologic examination revealed a single and multilayered sheet of anaplastic cells along the undersurface of the epidermis extending down hair follicles and present over a large area.


RESULTS
Three of the patients developed either a squamous cell carcinoma (SCC) or basal cell carcinoma (BCC) within the area encompassed by the AK.


CONCLUSIONS
These cases represent an insidious, proliferative form of AK with an increased tendency to develop into skin cancer.
Department of Dermatology, Baylor College of Medicine, Houston, Texas 77030.
L H
LH
Goldberg
A K
AK
Joseph
J A
JA
Tschen
D000368:Aged; D002280:Basal Cell Carcinoma / Q000473:pathology*; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D005260:Female; D006801:Humans; D007642:Keratosis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011230:Precancerous Conditions / Q000473:pathology*; D012008:Recurrence; D012867:Skin / Q000473:pathology; D012878:Skin Neoplasms / Q000473:pathology*