Acanthosis nigricans is a cutaneous disorder characterized by symmetric hyperpigmented velvety plaques on the neck, axillae, antecubital and popliteal fossae, inframammary, and groin areas. It is associated with acquired lipodystrophy.
Pathology
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).
Histopathology of acanthosis nigricans shows papillomatosis and hyperkeratosis of skin.
Treatment and prognosis
The malignant form can regress after treatment of the cancer while the therapy of choice for the benign form is debatable but weight loss is considered first line.