By Gary M. White, MD
Photograph courtesy of Dr. Kaess.
Malignant acanthosis nigricans (MAN) is a paraneoplastic condition in which acanthosis nigricans (AN) is precipitated by an internal cancer.
The typical velvety thickening of the skin occurs. In contrast to the classic (and much more common) AN, MAN is often more severe and affects skin in unusual places. In 277 cases reviewed in one study, the condition was associated with gastric carcinomas in 55.5% and other intra-abdominal carcinomas in 17.7%. Tripe palms is a variant where velvety thickening is seen on the palms. Verrucous or velvety thickening of the lips may occur (An. Bras. Dermatol. vol.86 no.3 Rio de Janeiro May/June 2011).
The malignancy should be found and treated.