Incidental granular parakeratosis associated with dermatomyositis.

A 43-year-old patient presented with a 4-month history of intermittently occurring symmetrical and slightly scaling erythematous plaques in his zygomatic regions. Because of polymyositis in the patient's history, the skin lesions were thought to be a manifestation of dermatomyositis. The skin biopsy revealed a sparse superficial perivascular infiltrate of lymphocytes, which was associated with telangiectases and both discrete vacuolar alteration and smudging of the dermal-epidermal junction. These findings were consonant with dermatomyositis. In addition to these features focal granular parakeratosis was present. The histopathologic presence of granular parakeratotic corneocytes above a zone of orthokeratosis and the absence of clinical features of granular parakeratosis indicate the granular parakeratosis is incidental.