CUTANEOUS LESIONS ASSOCIATED WITH INTERNAL MALIGNANCY.

Internal malignant tumours may stimulate the formation of tumour antigens which, by means of an antigen-antibody mechanism, can cause pruritus, ichthyosis, erythroderma, acanthosis nigricans, dermatomyositis, erythema-urticarial and vesiculo-bullous skin eruptions.Tumours may also interfere with normal immunity responses and allow various localized skin eruptions such as herpes zoster and epidermophytoses to escape their normal boundaries and become generalized.Skin malignancies may also be a sign of decreased immunoallergic response and by their presence alert the physician to search for an internal malignancy, either one associated with the skin lesion, such as a lymphoma, or an unrelated tumour.