[Acanthosis nigricans maligna--a gastrointestinal neoplasie. A review (author's transl)].

Acanthosis nigricans maligna (a. n. m.) is a well known paraneoplastic syndrome of the skin in 90 p. c. associated with tumours of the gastrointestinal tract (mostly gastric carcinomas) in contrast to pseudoacanthosis. Metastases are detected at the time of first diagnosis usually. Therefore, the a. n. m. may be the first sign of the tumour but does not represent an early symptom. The a. n. m. typically disappears with eradication of the responsible tumour and may reappear on its recurrence or metastasizing. In all cases an intensive search for gastrointestinal cancers is absolutely necessary. The etiopathology of the a. n. m. is still under advisement and the current state of knowledge is discussed in detail.