A young adult presents with a unilateral patch of slate-blue to brownish hyperpigmentation over the temple, cheek, and periorbital area following the ophthalmic and maxillary divisions of the trigeminal nerve. The ipsilateral sclera shows a bluish patch. Histology shows scattered spindle-shaped dendritic melanocytes in the upper dermis. What is the diagnosis?
- A Mongolian spot
- B Nevus of Ota ✓
- C Becker's naevus
- D Nevus of Ito
Correct answer: B. Nevus of Ota
Explanation
Nevus of Ota is a dermal melanocytosis presenting as unilateral blue-grey hyperpigmentation in the trigeminal V1 and V2 distribution, characteristically involving the sclera, with dendritic melanocytes scattered in the upper dermis. Nevus of Ito is identical histologically but occurs over the shoulder region supplied by the supraclavicular and lateral brachial cutaneous nerves. A Mongolian spot is congenital, lumbosacral, and fades in childhood without scleral involvement. Becker's naevus is a pigmented hairy plaque on the shoulder of adolescent males.
Reference: Fitzpatrick's Dermatology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.