Acanthosis nigricans and bile duct malignancy.

A case of acanthosis nigricans associated with a metastatic adenocarcinoma is presented. To our knowledge this is the first one reported in the literature. The primary tumour is unknown, but it is presumably a cholangiocarcinoma. The skin changes preceded the detection of malignancy by 2 years, during which the skin lesions progressed though the patient was still in good health. If malignant acanthosis nigricans is suspected and the underlying malignancy cannot be found at the initial screening, repeated screenings are necessary because of the time factor.