Practice Essentials
Stucco keratosis was first described by Kocsard and Ofner in 1965 and later by Willoughby and Soter in 1972. [1, 2]
Stucco keratosis is a keratotic papule that is usually found on the distal lower acral extremities of males. Stucco keratosis seems to appear with a higher frequency in males.
Usually, multiple lesions are found in stucco keratosis; in one study, between 7 and more than 100 lesions were noted on the patients. The lesion is asymptomatic, and patients usually do not complain of having the lesions. The name stucco keratosis is derived from the "stuck on" appearance of the lesions.
The lesions of stucco keratosis are benign growths similar to those of seborrheic keratosis. Clinically, stucco keratosis lesions may be mistaken as a melanoma.
No laboratory or imaging studies are required in stucco keratosis. If the diagnosis is in question, then a shave biopsy can be performed to confirm the diagnosis.
Stucco keratosis is a benign lesion that can be removed by curettage or cryotherapy.
Patients with stucco keratosis can be informed that the lesions are not cancerous. Because lesions are found in elderly patients, the patients can be taught the "ABCDEs" of melanoma. Patients with stucco keratosis should be advised to have a periodic skin examination.
Pathophysiology
Stucco keratosis appears to be produced by thickening of the epidermis. On microscopic examination, the epidermis is usually exophytic with a church spire–like appearance. The surface may be regularly distributed into folds with elongation of papillae. The stratum corneum is thickened.
Surface friction may contribute to the development of stucco keratosis lesions. The tumor grows outward and does not penetrate into the dermis. The lesions are usually found in elderly patients.
With a nested polymerase chain reaction technique, human papillomavirus types 9, 16, 23b, DL322, and 37 were detected in a 75-year-old nonimmunosuppressed man with very extensive stucco keratosis lesions. [3] This finding requires confirmation in other patients.
Various genetic mutations, including PIK3CA and FGFR3 have been reported in common seborrheic keratoses. [4] A 2010 study demonstrated that 3 of 5 stucco keratosis samples revealed a PIK3CA mutation, but not the FGFR3 mutation. [5] Further study will likely highlight the genetic background for stucco keratoses.
Epidemiology
The incidence of stucco keratosis is approximately 10% of the senior population in the United States. Stucco keratosis predominantly occurs in elderly men. Stucco keratosis is found in persons of all races. No reports have been noted on race as a factor in stucco keratosis.
The incidence of stucco keratosis is higher in males than in females. Elderly people are susceptible to stucco keratosis. The stucco keratosis lesions begin to appear around age 45 years.
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Stucco keratosis in a 70-year-old male veteran. A few scattered white plaques are on the lower extremity.
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Photomicrograph of characteristic church spires of stucco keratosis.
