ABSTRACT
The skin may reect many visceral diseases, malignancies included. Sometimes, the skin may even give a clue to the underlying neoplasm. The Swiss dermatologist Delacrétaz has dened the term “paraneoplasia”:
The paraneoplastic signs or syndromes may precede, appear parallel to, or follow the appearance of the internal malignancy. There are many classications of the paraneoplastic signs and syndromes, utilizing a variety of criteria. Some of them are based on the morphology of skin changes, while others are based on the frequency of the association of dermatosis/visceral malignancy. The paraneoplastic signs and syndromes may be divided into two groups: indirect associations and direct associations with parallel evolutions corresponding to the paraneoplastic syndrome. The pathogenesis of the development of paraneoplasias includes
• Peptides, mediators, and hormones released from the tumor
• Immunologic defense reactions induced by the tumor antigens and appearing after cross-reaction with the structures of the skin
• Deposits of immunocomplexes of tumor antigens and antibodies2
Metastases to the skin are more specic signs of internal cancer. Sister Mary Joseph nodule (Figure 26.1) may be considered more as metastases from an intraabdominal malignancy. Clinically, the Sister Mary Joseph nodule is an indurate nodule or plaque. The surface of the nodule is sometimes ulcerated with exudation of purulent or mucosal discharge. Occasionally, the lesions form a tumor. Sister Mary Joseph nodules are signs of an advanced intraabdominal malignancy. They appear as a sign of previously diagnosed neoplasia. The primary malignancy is localized in the gastrointestinal or genital tract, mainly as gastric adenocarcinoma, but also as adenocarcinoma of the ovary, colon, pancreas, prostate, or liver.4
