title: Solitary actinic porokeratosis.
abstract: An 83-year-old man experienced abrupt onset of a solitary lesion of porokeratosis on his bald, actinically damaged scalp. The features in this case are unusual and represent another point in the broad spectrum of lesions characterized by the cornoid lamella of porokeratosis.
mesh_terms: D000368:Aged; D006801:Humans; D007642:Keratosis / Q000209:etiology / Q000473:pathology*; D008297:Male; D012536:Scalp Dermatoses / Q000209:etiology / Q000473:pathology*; D012867:Skin / Q000473:pathology*; D013472:Sunlight