Clinical and histopathologic study of benign lichenoid keratosis on the face.

Benign lichenoid keratosis is a cutaneous entity that consists of a nonpruritic papule or slightly indurated plaque that is histologically characterized by a band-like inflammatory infiltrate with interface involvement. The purpose of this study was to investigate the clinical and histopathologic features of benign lichenoid keratosis localized on the face. Fourteen benign lichenoid keratosis patients diagnosed clinically and histopathologically in our clinic during the 10-year period from 2002 to 2012 were studied. Thirteen female and 1 male patients were included. The mean age at diagnosis was 46.5 years. The color of most of the lesions was brown (10 cases, 71%). The cheek was the most commonly involved area (10 cases, 71%). All of the lesions were single. There were 9 (64%) flat lesion cases and 5 (36%) raised lesion cases. Most patients denied having any symptoms; 3 had mild pruritus. The histopathological findings indicated that all the cases exhibited lichenoid inflammatory infiltrate obscuring the dermal-epidermal junction and vacuolar alteration of basal cell layer. The lesions showed focal parakeratosis (79%), melanophages (79%), hyperkeratosis (71%), and necrotic keratinocytes (71%). Solar elastosis (50%) and acanthosis (43%) were also seen frequently. Diagnosis of benign lichenoid keratosis should be made by a combination of clinical manifestations and histopathological findings. In particular, benign lichenoid keratosis should be considered if a middle-aged patient presents a solitary asymptomatic brown lesion on the face. We think benign lichenoid keratosis may be a specific disorder rather than the inflammatory stage of regressing solar lentigines, large cell acanthoma or reticulated seborrheic keratosis.