Malignant acanthosis nigricans can accompany, precede or follow the onset of internal malignancy. Most cases are associated with an adenocarcinoma, most commonly of the stomach, but also the lung and breast. Other types of internal malignancies have been noted as well. It is more common in males but also can be found in females. Tripe palms, as pictured above, is palmar acanthosis nigricans. Here's a trick: if a nonobese male over the age of 40 develops acanthosis nigricans, particularly on the palms where there are thickened, velvety palms and pronounced dermoglyphs, then work him up!!! Although it is not pathognomonic, up to 95% of tripe palm patients have an associated with internal malignancy.