Stucco keratoses. A clinico-pathological study.

Stucco keratoses are benign acquired papular warty lesions which usually occur on the distal parts of the lower limbs of elderly men. Their nature and pathogenesis are uncertain. Eight patients with multiple stucco keratoses who presented to the Cardiff Dermatology Department over an 18-month period were studied in an attempt to characterize these lesions. All subjects were male, with ages ranging from 50 to 72 years. Their lesions were most numerous over the fronts of the lower legs, but were also evident over other areas of the limbs. Most patients had a history of prolonged solar exposure, but the relationship of this to the development of the lesions was uncertain. Histologically there were no dysplastic changes and a characteristic regular 'church spire' type retention hyperkeratosis without marked acanthosis was evident. Lack of a marked increase in the epidermal cell population size is reflected in the normal in vitro tritiated thymidine autoradiographic labelling indices (7.81 +/- 1.67%, normal range 5 to 9%). Ultrastructurally no viral particles were evident and a normal pattern of epidermal differentiation with hypergranulosis was present. Two of the patients with myriads of lesions who were treated for 2 months with etretinate showed a dramatic clinical improvement which, however, lasted for 6 months only.