What skin condition is characterized by hyperpigmentation found in body folds?

Acanthosis nigricans is characterized by hyperpigmentation that typically occurs in body folds, such as the neck, armpits, and groin. This skin condition is often associated with insulin resistance and can be an indicator of metabolic syndrome or type 2 diabetes. The affected areas become darker and thicker, presenting a velvety texture that distinguishes it from other skin conditions.

In contrast, other options do not primarily feature hyperpigmentation in body folds. Freiberg disease pertains to a condition affecting the foot, specifically the second metatarsal, and does not involve cutaneous changes like hyperpigmentation. Psoriasis is a chronic autoimmune condition marked by red, scaly patches on the skin, and eczema (or atopic dermatitis) leads to itchy, inflamed skin, often without the specific hyperpigmentation associated with acanthosis nigricans. Thus, the defining feature of hyperpigmentation in body folds makes acanthosis nigricans the correct choice.