Extensive Acanthosis Nigricans due to rectal carcinoma (3 of 7)

Suspicion for malignancy-associated acantosis nigricans
should arise when it occurs when resent onset in a
non-obese patient who does not have diabetes.

Acanthosis nigricans presents as a smooth, thickened, and
dark appearance to the skin in body fold areas, most often
in the axilla and around the neck If extensive, it may lead
to a striking appearance, with thickening of the palms and
soles and oral lesions of hyperkeratosis. Acrochordons (or
skin tags) may also occur in affected sites. This clinical
presentation is most often seen without malignant disease
in obese patients, in certain insulin-resistant diabetes
syndromes, as a familial trait, and with certain medications.