|Year : 2021 | Volume
| Issue : 2 | Page : 141-144
Neha Sud1, Resham Vasani2
1 Consultant Dermatologist, Manav Sewa Sangh, Mumbai, Maharashtra, India
2 Bhojani Clinic, Mumbai, Maharashtra, India
|Date of Submission||21-Apr-2020|
|Date of Decision||29-Apr-2020|
|Date of Acceptance||03-May-2020|
|Date of Web Publication||31-Mar-2021|
Bhojani Clinic, Earth Classic, Babasaheb Ambedkar Road, Matunga, Mumbai - 400 019, Maharashtra
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Sud N, Vasani R. Mongolian spots. Indian J Paediatr Dermatol 2021;22:141-4
| What is Dermal Melanocytosis?|| |
It is a group of conditions characterized by the presence of melanocytes in the dermis. They represent the arrest in the migration of the melanocytes from the neural crest to the basal layer of the epidermis during fetal life and share a common embryonal pathogenesis. Melanoblasts, parent cells of melanocytes, arise from the neural crest. Melanocytes then migrate via the dermis to the basal layer of the epidermis by the 11th–14th week of gestation. Inability of melanocytes to completely migrate to the epidermis by the 20th week of gestation and failure of the clearance of dermal melanocytes (DMs) by macrophages results in DM.
| What Conditions Are Included under Dermal Melanocytosis?|| |
Conditions included under this heading are Mongolian spot, nevus of Ota, nevus of Ito, and DM hamartoma.
| What Are Mongolian Spots?|| |
Mongolian spots (MSs) present at birth or in the first few weeks of life as varying shades of blue-green, gray, or blue-black, uniform, noninfiltrated, nonblanching discoloration resembling a bruise seen most commonly in the lumbosacral region (80%)., The lesions can be single or multiple, round, or oval ill-defined patches.
MSs are seen more commonly in newborns of Asian and African descent.
They were described in Mongolians by a German professor, Edwin Baelz, who named them as MSs. On an average, the prevalence of MS is around 10% in White infants, 50% in Hispanics, and 90%–100% in Asians and Africans.
| What is the Natural Evolution of Mongolian Spot?|| |
MS lesions evolve through two stages:
- Stage of evolution: DOPA positive
- Stage of regression: DOPA negative.
MSs presenting at birth tend to regress spontaneously in the first 2 years of life and are mostly not found after early childhood. There may be an initial period of increase in depth in infancy.
A prospective study by Gupta and Thappa showed that nearly 40% of the lesions in 1524 patients they followed up cleared by 1 year of age.
Regressing lesions show a progressive loss of the protective sheath around the DMs, seen on electron microscopy. This destruction normally starts in fetal life but may be delayed in persistent patches. Genetic factors, dysregulated melanocyte proliferation, local excess of growth factors, and close proximity of DMs to surrounding blood vessels are postulated as other contributing factors.
| What Are the Atypical Presentations of Mongolian Spot?|| |
- Aberrant MS: Lesions present on areas other than classically described, as on the upper back, face, legs, and chest. The lesions can be more than one and have a tendency to persist
- Extensive MS: Lesions in a widespread or generalized distribution
- Persistent MS: Lesions persisting beyond childhood into adult life. Extrasacral, dark, large (>10 cm), multiple, and widespread MSs tend to be more persistent,
- Progressive MS: Lesions increasing in number, with new areas involved beyond early months of life
- Acquired MS: Lesions may be first apparent in later years of life, considered to be the result of activation of dormant DMs
- Superimposed MS: A darker pigmented MS superimposed on another MS. This may be the result of two different waves of melanocyte migration or arrest of melanocytes at two dermal levels during migration
- Speckled MS: Mottled or dotted gray-blue macules of different hues can be seen.,
| Name the Phenomena Described with Mongolian Spot?|| |
Local hindrance phenomenon
The local geography of a region hinders the transfer of the melanocytes therein. Hence, MS does not involve the perianal area. A similar phenomenon is noted with nevus of Ota where it does not extend beyond the nasolabial fold.
Longer wavelength visible light penetrates deeper into the skin than shorter wavelengths (blue), which get scattered and dispersed at a superficial level. Therefore, the color variations, blue to gray, of the otherwise black dermal melanin in MS. The depth, number, and melanin content of the melanocytes determine the color.
Café au lait macules and melanocytic nevi when present within a MS may show a pale area surrounding them. This halo-like phenomenon results from the disappearance of the MS around the café au lait spots, revealing normal pigmented skin. Temel et al. suggested the term “phacomatosis pigmento-halo-pigmentalis” for the same.
| What Are the Dermoscopic Features of Mongolian Spot?|| |
An ill-defined grayish-green patch is seen on dermoscopy.
| What is the Histopathology Picture in Mongolian Spot?|| |
Lower half to two-thirds of the dermis shows spindle-shaped, elongated, and slender dendritic cells containing melanin granules. These dendritic cells can be seen around neurovascular bundles and in a ribbon-like pattern between the collagen fibers., Fibrosis and melanophages are absent.
Ultrastructurally, these melanocytes are invested by a parallel extracellular dermal sheath made up of granules and filaments. The persistence of this sheath has been postulated as one reason for long-standing MS.
Special stains: S-100, HMB-45, Melan-A/MART-1, tyrosinase, PNL2 Ag, and MITF.
| What Differentials Need to be Considered?|| |
Bruises secondary to child abuse or nonaccidental injury: Painful, shorter course with characteristic color evolution.
Other DMs: Characteristic location and persistent speckled pattern. Dermoscopy of nevus of Ota shows hypopigmented globules surrounded by a pigmented background. On histopathology (HPE), the DMs are more numerous and located more superficially in the dermis compared to MS.
Blue nevi: Generally acquired, dark blue-to-black macules to dome-shaped papules. Rarely congenital lesions have been reported.
| What Are the Clinical Pointers that Warrant Further Investigation in Mongolian Spot?|| |
Although there are no specific investigations to be done in the case of MS, some presentations warrant screening for inborn errors of metabolism (IEMs), vascular birthmarks, and spinal dysraphism.
They include cases with,
- Extensive MS
- Persistent lesions
- Progressive lesions
- Involvement of the anterior trunk
- Lesions having feathery indistinct borders.
| What Are the Common Associations of Mongolian Spot?|| |
The associations of Mongolian spot are enlisted in [Table 1].,,,,,,. Metabolite accumulation in IEMs results in stimulation of nerve growth factor (NGF) activity through Trk protein, a high-affinity tyrosine kinase-type receptor for NGF binding. These Trk receptors are present on nerve cells, keratinocytes, dermal fibroblasts, and melanocytes too. Defective mechanism involving the NGF or altered Trk receptor interaction has been postulated in the arrest of normal transdermal melanocyte migration in the dermis and activation of the melanin-synthesizing pathways of latent DMs. Hurler's syndrome and GM1 gangliosidosis [Figure 1]a, [Figure 1]b, [Figure 1]c, [Figure 1]d are the most common IEMs associated with MS.,,,
|Table 1: Common associations of Mongolian spots,,,,,|
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|Figure 1: (a-d) Aberrant, extensive, and mottled Mongolian spots with associated generalized telangiectasia in a case of GM1 gangliosidosis|
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Neurocristopathies are disorders characterized by abnormalities in neural crest migration, growth, and differentiation., Abnormal migration of melanocytes and angiogenic cells adversely affecting each other may result in phakomatosis pigmentovascularis. This term denotes the association of cutaneous vascular malformations, pigmentary abnormalities, and DM. MS may also occur as a marker of occult spinal dysraphism [Figure 2].,
|Figure 2: Mongolian spot associated with port wine stain and spinal dysraphism|
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| Is Any Active Intervention Required?|| |
Early recognition and timely intervention, with stem cell transplantation and enzyme replacement, can reduce chances of permanent organ damage in storage disorders like mucopolysaccharidoses associated with MS. In cases of MS associated with IEM, the diagnosis gives the family options not only for family planning but also for early palliative care decisions.
Otherwise, keeping in mind the majorly self-limiting course of this benign condition, no active intervention is required. Q-switch lasers (ruby, alexandrite, and neodymium-doped yttrium aluminum garnet) and intense pulsed light have been used in persistent lesions, with guarded results, especially in adults and sacral MS.,, Hence, laser treatment if initiated for persistent MS should be done before 20 years of age.
| Conclusion|| |
MSs have been known to be a benign cutaneous manifestation in the newborn period until our knowledge horizons widened with reports suggesting its association with lysosomal storage disorders and neurocristopathies. Hence, all cases of atypical MS should be followed up and screened for these underlying genetic conditions as timely interventions where available can avert major organ affliction and damage.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]