A 55-year-old woman complains to her physician that the skin of her armpits and groin "keeps getting darker and darker." Physical examination demonstrates velvety brown and way skin in the axilla and groin. Biopsy of these lesions shows a variably hyperplastic epidermis with many sharp peaks and valleys. Aside from cosmetic considerations, which of the following is the primary medical significance of these lesions?

The lesions are acanthosis nigricans, which looks somewhat like a mole or wa, but is actually due to epidermal hyperplasia. Acanthosis nigricans can be seen in obesity, diabetes, and in patients with underlying cancers, often adenocarcinomas of the chest or abdomen. The lesions are not characteristic of immunosuppression and are not easily superinfected. They are also neither malignant nor premalignant. Ref: Suurmond D. (2009). Section 5. Miscellaneous Epidermal Disorders. In D. Suurmond (Ed), Fitzpatrick's Color Atlas & Synopsis of Clinical Dermatology, 6e.