[Cutaneous metastases in digestive cancers (author's transl)].

Cutaneous metastases are seldom encountered in digestive cancers. The mechanism of their formation explains their low rate. The metastases spread mainly by the lymphatic system (especially in diffuse, spotty or pseudo-elephantiasic forms and in regional forms), however numerous lymph node filters found through out the lymphatic system limit the progression of neoplasic cells. On the contrary, metastases most often spread by retrograde involvement due to blocking of the lymphatic system. As for hematogenous metastases (generalized nodular forms or aberrant localizations), they are observed even less frequently than lymphatic ones; metastatic embolisms may effectively become blocked in capillaries, especially in the lungs and the liver, which constitutes a double barrier before the skin may be involved.