Congenital Dermal Melanocytosis (Mongolian Spot)

Updated: May 23, 2016
  • Author: Abdul-Ghani Kibbi, MD; Chief Editor: Dirk M Elston, MD  more...
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Overview

Background

Mongolian spot refers to a macular blue-gray pigmentation usually on the sacral area of healthy infants. Mongolian spot is usually present at birth or appears within the first weeks of life. Mongolian spot typically disappears spontaneously within 4 years but can persist for life.

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Pathophysiology

Mongolian spot is a congenital, developmental condition exclusively involving the skin. [1] Mongolian spot results from entrapment of melanocytes in the dermis during their migration from the neural crest into the epidermis. This migration is regulated by exogenous peptide growth factors that work by the activation of tyrosine kinase receptors. It is postulated that accumulated metabolites such as GM1 and heparan sulfate bind to this tyrosine kinase receptor and lead to severe neurologic manifestations and aberrant neural crest migration.

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Epidemiology

Frequency

United States

More than 90% of Native Americans, 80% of Asians, and 70% of Hispanics have Mongolian spots; less than 10% of whites have Mongolian spots. A recent study on the prevalence of birthmarks and transient skin lesions in 1000 Spanish newborns conducted at a neonatal clinic has revealed a proportion of 0.189 for Mongolian spots, with a confidence interval of 0.164-0.213. [2]

More recently, a prospective clinical study of cutaneous findings in newborns in the United States has shown an overall incidence of 14% for dermal melanocytosis over the sacrum and buttocks. When these patients were analyzed according to ethnicity, the incidence was 29% in Asians, followed by others (unspecified ethnicity), Hispanics, African Americans, and whites. [3]

International

The prevalence of Mongolian spots varies among different ethnic groups. This condition is most common among Asians. Mongolian spot has also been reported in 80% of East African children, in 46% of Hispanic children, and in 1-9% of white children. [4]

The incidence of Mongolian spot was not significantly associated with sex, gestational age, mother's age group, or delivery type at 2 hospitals in Iran. However, in one of the hospitals in which this observational study was done, mongolian spots were shown to be significantly associated with a high birth weight (≥2500 g). [5]

In cross-sectional study on 203 healthy neonates in a Brazilian public hospital, a greater incidence was found in nonwhite, black, and Asian babies. [6]

A case-controlled study conducted in Turkey on 50 patients with Down syndrome showed that Mongolian spot was among the most common mucocutaneous disorders; it was seen in 22% of patients and in 6% of healthy controls with a P -value of 0.018. [7]

Race

Mongolian spots are observed in more than 90% of infants of the Mongoloid race (ie, East Asians, Indonesians, Polynesians, Micronesians, Amerindians, Eskimos).

Sex

No sex predilection is reported for Mongolian spot.

Age

Mongolian spot is usually present at birth, but it can also appear within the first weeks of the neonatal period.

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Prognosis

Mongolian spots usually fade in the first year of life, but, at times, they may persist indefinitely. However, melanocytes may persist in the dermis when examined histologically. [8] Aberrant Mongolian spots located in areas distal from the lumbosacral region may persist, unlike the typically located ones, which have a tendency to resolve. [9]

Gupta and Thappa followed 1524 infants with Mongolian spots and found that 42% of these lesions disappeared completely by age 1 year. They demonstrated that large sizes (>10 cm), extrasacral location, dark-colored lesions, and multiple patches are more likely to persist beyond 1 year. The authors also postulated that infants with Mongolian spots persisting beyond age 1 year might be at increased risk for inborn errors of metabolism. [10]

Mongolian spot is not associated with mortality or morbidity. However, three cases of congenital aplasia cutis were reported by Japanese authors in concomitance with dermal melanocytosis, but not with the typical distribution of the Mongolian spot, in two males and one female. [11, 12]

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