"Acanthosis nigricans is a cutaneous disorder characterised by symmetric hyperpigmented velvety plaques on the neck, axillae, antecubital and popliteal fossae, inframammary, and groin areas. It is associated with acquired lipodystrophy."
"The benign form of acanthosis nigricans is associated with insulin resistance and diabetes. The malignant form is associated with adenocarcinomas (e.g. the stomach, ovary, kidney, bladder, bile duct, pancreas)."