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| Fig. 37.5 Sister Mary Joseph nodule. Metastatic lesion of colon cancer to the umbilicus. |
The skin may be involved with GI tract malignancy in several ways. First, the skin may be a site of metastasis from a primary GI tract cancer. This happens most frequently with adenocarcinoma of the colon (Fig. 37-5). Secondly, the skin and GI tract may be both affected by a genetic disease, such as the pancreatic cancer syndrome associated with multiple atypical nevi and melanoma (chromosme 9p21,
CDKN2A). There is also a large group of paraneoplastic dermatoses, that is, a skin condition associated with an underlying malignancy (indirect involvement). Examples include “malignant” acanthosis nigricans, superficial migratory thrombophlebitis, and glucagonoma syndrome. In a few instances, such as excess glucagon secretion in the glucagonoma syndrome, the link between the skin and gut is clear. In other cases (such as acanthosis nigricans), the skin condition may occur in many individuals without cancer, so a thorough evaluation of the patient is necessary.
Thiers BH, Sahn RE, Callen JP:
Cutaneous manifestations of internal malignancy, CA Cancer J Clin 59(2):73–98, 2009.
