A healthy 32-year-old woman presented to the clinic with a 1-year history of progressive asymptomatic hyperpigmented macules on the lips and longitudinal hyperpigmentation of the left thumb extending to the cuticle. There was no relevant drug or positive family history or evidence of other pigmented lesions. On examination, there was linear, brownish, reticular pattern on both inner aspects of her lips and longitudinal melanonychia in the left thumb extending to the cuticle on the middle aspect of the nail.
Laboratory tests, Chest X-ray and abdominal ultrasound were normal. Colonoscopic findings were negative for any gastrointestinal pathology or tumorous formations associated with oral hyperpigmentations. Based on the endocrinologist's exam adrenal insufficiency was ruled out and histological examination of the lip lesions revealed non-specific changes such as acanthosis and…
