Lichen nitidus of the palms: a case with peculiar histopathologic features.

Palmar involvement in lichen nitidus is infrequent. In such cases, the histopathologic findings of palmar lesions are usually identical to those of extrapalmar ones. We report on the case of a patient with multiple tiny papules located on the palms and elbows. A biopsy specimen from the elbow showed the typical features of lichen nitidus, but a biopsy from the palm disclosed an inflammatory infiltrate mostly disposed around the bases of rete ridges and composed of lymphocytes and histiocytes with some giant cells both in the dermis and in the epidermis. This location of the infiltrate is similar to that found in hypertrophic lichen planus, a combination of lichen planus and lichen simplex chronicus. We conclude that this histopathologic feature in palmar lichen nitidus could be the result of the superimposition of lichen nitidus on normal palmar skin, resulting in a picture resembling hypertrophic lichen planus.