A 45-year-old obese patient presents with these lesions over her neck. What is your diagnosis?

Ans. A. Acanthosis nigricansAcanthosis nigricans is a common condition characterized by velvety, hyperpigmented plaques on the skin.Sites affected: Neck and axillaeMost common association: ObesityPathogenesis:Association of acanthosis nigricans with multiple disorders characterized by insulin resistance suggests that hyperinsulinemia plays a key role in the development of acanthosis nigricans. Elevated levels of insulin may stimulate keratinocyte and dermal fibroblast proliferation via interaction with IGFR1 (Insulin-like growth factor receptor-1), resulting in the plaque-like lesions that typify the disorder