Two cases of late onset Ota's naevus

Pruritic acquired nevus of Ota

Nevus of Ota is a unilateral, asymptomatic cutaneous and mucosal hyperpigmentation of the face that is congenital or may appear during childhood. We present a case of symptomatic acquired nevus of Ota in an adult, associated with intense pruritus, not described in the literature so far. A 32-year-old woman presented with brownish mottled macules which appeared on her face progressively over 8 days, following the distribution of the first and second divisions of the left trigeminal nerve and partially covering the iris and sclera of the left eye. She reported an intense pruritus in this area. We performed a biopsy on the left forehead, which confirmed the diagnosis of nevus of Ota. Specific stains and immunohistochemistry revealed increased numbers of mast cells. Ophthalmological tests showed acute acquired melanocytosis of the left iris and sclera. The origin of the nevus is still unclear. Several hypotheses suggest a reactivation of melanocytes during their migration from the neural crest. The pruritus reported in our patient may be explained by the increased quantity of mast cells observed in the lesion and/or neuronal stimulation of the ophthalmic and maxillary divisions of the fifth cranial nerve.

Late-onset Ito?s nevus: An uncommon acquired dermal melanocytosis

Dermal melanocytoses comprise a variety of congenital and acquired conditions characterized by a sparse population of intradermal dendritic, variably pigmented, spindle-shaped melanocytes. While Mongolian spot, Ota's and Ito's nevi are usually present at birth or appear around puberty; acquired dermal melanocytoses that appear in adult life are extremely rare. They include the facial lesions of acquired bilateral nevus of Ota-like macules, also named Hori's nevus, and the acquired unilateral nevus of Ota, also known as Sun's nevus. Uncommon extrafacial examples of acquired dermal melanocytoses include lesions involving upper extremities, wrist, back, lower extremities and dorsal aspects of the hands and feet. They are more prevalent among Asian women. In general, dermal melanocytoses are rare lesions in Caucasian patients and acquired variants are exceedingly uncommon. We report a rare example of acquired Ito's nevus that appeared in a Caucasian elderly woman and review the literature about acquired dermal melanocytoses.