Nevus of Ito in Adult
It shares clinical and histopathologic features, aside from location, with other dermal melanocytoses including nevus of Ota (trigeminal distribution), congenital dermal melanocytosis (formerly known as a Mongolian spot in the lumbosacral distribution), and dermal melanocyte hamartoma. Dermal melanocytoses are caused by an increased number of dermal dendritic melanocytes and can be congenital or acquired. All dermal melanocytoses are more often seen in patients of Asian or African descent, and nevus of Ito, in particular, is more common among females.
Unlike the more common congenital dermal melanocytosis, nevus of Ito lesions do not spontaneously regress and may darken or grow in size with puberty. These changes are thought to be secondary to ultraviolet radiation and hormonal influences. Patients have noted sensory changes in the area of the nevus of Ito. Extremely rarely, melanoma arising in a nevus of Ito has been reported.
D22.9 – Melanocytic nevi, unspecified
48543002 – Nevus of Ito
- Blue-gray spots seen in congenital dermal melanocytosis typically overlie the buttocks or lumbosacral area.
- Nevus of Ota is characteristically in the trigeminal distribution of the face.
- Dermal melanocyte hamartoma is extremely rare but can present in a generalized or dermatomal pattern on the extremities or a segmental pattern on the face, neck or trunk. Histopathologically, pigment is often more superficial than other dermal melanocytoses.
- Blue nevus may have similar blue to gray pigmentation but is a smaller, well-demarcated macule or papule.
- Drug-induced pigmentation can either be diffuse or photodistributed.
- Ecchymoses will have a history of trauma and can have more varied coloration.
- Arteriovenous malformations can range from blue to red, and pulsations may be heard on Doppler.
- Becker nevus can be found in a similar distribution but is often tan or brown with coarse hair arising during adolescence.
- Lentigines (solar, simplex) or giant café au lait macules typically impart a tan to brown hue.
- Nevus spilus presents with a tan to brown background patch with darker speckled pigmentation within.
- Melanoma can manifest with disseminated melanosis, but pigmentation will usually be less well-demarcated and will present later in life.