A 37-year-old male presented to the dermatology clinic with complaints of pigmentation in the axillae and groin for the past 15 years which was increasing gradually and was occasionally itchy. On close examination, it showed bilateral reticular pigmentation of axilla (Fig. 22.1), lower abdomen and upper part of thighs (Fig. 22.2). Lentigo-like and comedo-like lesions were also present over these areas. He denied any history of drug intake, intolerance to heat, decreased sweating, skin atrophy or involvement of extremities. There is history of similar lesions in his father.

Based on the case description and the photograph what is your diagnosis?