| • | a cutaneous marker, most commonly of insulin resistance and less frequently of a malignancy |
| • | concerned when patient is >40, not obese, and with sudden onset |
| • | malignancy below diaphragm (GI tract/stomach) |
| • | pathogenesis (when not associated with malignancy) – insulin resistance leads to hyperinsulinemia, which favors increased binding of insulin to IGF (insulin-like growth factor) receptors |
| • | hyperinsulinemia may also trigger the ovarian hyperandrogenism that commonly coexists with acanthosis nigricans in women with severe insulin resistance |
| • | ddx: CARP, Dowling-Degos disease |
| • | treatment: obese patients can reverse the changes with weight loss |
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