The cutaneous manifestations of gastrointestinal malignancy.

The skin is often the herald of an underlying systemic illness, and gastrointestinal malignancies can present in numerous ways in the skin. Paraneoplastic phenomenon, such as acanthosis nigricans and tripe palm, may be the first indicator of a gastrointestinal malignancy. In addition, gastrointestinal cancers can metastasize to the skin, as described in the well-known Sister Mary Joseph's nodule. Inflammatory systemic conditions such as dermatomyositis and multicentric reticulohistiocytosis can be associated with underlying malignancy. Finally, in numerous genetic syndromes with underlying malignancies, such as Muir-Torre, recognition of the skin signs leads to early diagnosis and screening.