[Cutaneous metastases of internal cancers]

Cutaneous metastases from internal tumours are relatively rare, appearing in ca. 4.5 percent of the cases, but their recognition is important; indeed, even though they usually appear during a known neoplastic disease, they may be the presenting sign of a hitherto unknown tumour. They may also constitute the first manifestation of relapse of a tumour considered to be in complete remission. Cutaneous metastases generally manifest as solitary or multiple nodules devoid of specific clinical features, over the head, chest and abdominal wall. They are mainly due to cancers of mammary origin in women, or of pulmonary, renal and gastrointestinal origin in men. Any histological type may be encountered, with a predominance of adenocarcinomas. The histological aspect often does not allow recognition of the primary site, which can be identified in selected cases by immunohistochemical studies. Although long survivals have exceptionally been observed after the development of cutaneous metastases, their occurrence usually has an ominous prognostic significance and considerably reduces the chances for an efficient treatment.