Case for diagnosis
Female patient, 42 years-old, without any noticeable personal or familial history, has\npresented, for the last four years, keratotic papules, some crusted, in a reddish-brown\ncoloration, linearly distributed along the left mammary region (). The patient presents similar lesions following the\nBlaschko lines from the left flank to the hypogastrium and also on the pretibial area of\nthe left leg (). These are pruriginous\nlesions that are exacerbated by the heat. There are no alterations to the palmar-plantar\nregions, mucosae or nails.\nThe histologic examination of an inter-mammary papule shows hyperkeratosis with areas of\nparakeratosis, acanthosis and suprabasal acantholysis associated to corps ronds and\ngrains, besides a superficial inflammatory perivascular infiltrate formed by lymphocytes\n().