|Year : 2015 | Volume
| Issue : 1 | Page : 32-35
Pigmentary mosaicism with left hemihypertrophy and syndactyly: Case report with review of literature
Sahana M Srinivas1, Madhuri Maganthi2, GN Sanjeev3, Jayalaxmi S Aihole4
1 Department of Pediatric Dermatology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
2 Department of Genetics, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
3 Department of Pediatrics, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
4 Department of Pediatric Surgery, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
|Date of Web Publication||16-Jan-2015|
Sahana M Srinivas
Department of Pediatric Dermatology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka
Source of Support: None, Conflict of Interest: None
Pigmentary mosaicism is a spectrum of disorders characterized by dyspigmentation along the lines of blaschko and other patterns such as phylloid, checkerboard and patchy pigmentation without midline separation. This group of disorders may be associated with or without systemic abnormalities. Pigmentary mosaicism includes hypomelanoses of Ito, linear and whorled nevoid hypermelanosis, phylloid hypo- and hypermelanosis and pigmentary mosaicism of both hypopigmented and hyperpigmented type. We describe a case of pigmentary mosaicism with constellation of multiple extracutaneous abnormalities.
Keywords: Constipation, hemihypertrophy, pigment mosaicism, syndactyly
|How to cite this article:|
Srinivas SM, Maganthi M, Sanjeev G N, Aihole JS. Pigmentary mosaicism with left hemihypertrophy and syndactyly: Case report with review of literature. Indian J Paediatr Dermatol 2015;16:32-5
|How to cite this URL:|
Srinivas SM, Maganthi M, Sanjeev G N, Aihole JS. Pigmentary mosaicism with left hemihypertrophy and syndactyly: Case report with review of literature. Indian J Paediatr Dermatol [serial online] 2015 [cited 2020 Oct 20];16:32-5. Available from: https://www.ijpd.in/text.asp?2015/16/1/32/149427
| Introduction|| |
Pigment mosaicism is a term used for all pigment anomalies caused by chromosomal mosaicism. It is characterized by hypo-or hyperpigmented lesions along the Lines of Blaschko More Details, phylloid, checker board pattern and patchy pigmentation without midline separation. It is an umbrella term that includes conditions hypomelanoses of ito (HI), linear and whorled nevoid hypermelanosis (LWNH), phylloid hypo- and hypermelanosis and pigmentary mosaicism of hypopigmented and hyperpigmented type.  We describe a case of hyperpigmentation along the lines of blaschko associated with left hemihypertrophy and syndactyly with gastrointestinal disturbances and review the literature of pigment mosaicism.
| Case report|| |
A 6-year-old male child presented to our department for evaluation of hyperpigmented skin lesions on trunk and extremities from birth. He was a post term child, born out of third degree consanguineous marriage. Natal and post natal history was normal. There was no history of blisters at birth. The child had history of constipation from past 1 year. There was no history suggestive of neurological or other systemic involvement. Family history was noncontributory. General physical examination showed normal vitals. Child had low set ears, hypertelorism, and hemihypertrophy of left side of the body [Figure 1]. Cutaneous examination showed streaks of hypopigmentation and hyperpigmentation present along the lines of blaschko on the neck, flexor and extensor aspect of both upper and lower limbs [Figure 2] [Figure 3] [Figure 4]. There was syndactyly of 3 rd and 4 th finger of left hand and partial syndactyly of 2 nd and 3 rd toe of both feet [Figure 5]. Teeth showed irregular spacing. Systemic examination was normal.
Hematological and serum chemistry profile was normal. Thyroid function test showed normal T3, T4 and increased thyroid stimulating hormone (9.25 mIu/ml, normal range: 0.34-5.6 mIu/ml) that required long-term follow-up. Computed tomography scan of brain, ultrasound abdomen and two-dimensional echo was normal. Parents did not give consent for skin biopsy for fibroblast culture. Karyotyping from peripheral blood was normal. On the basis of clinical findings, a diagnosis of pigment mosaicism with skeletal abnormalities (left hemihypertrophy, syndactyly, facial dysmorphism) with gastrointestinal abnormalities (constipation) was made.
|Figure 2: Hyperpigmentation present along the lines of blaschko on the neck|
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|Figure 3: Streaks of hyperpigmentation and hypopigmentation along the blaschko lines on flexor aspect of both upper arms and forearms|
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|Figure 4: Closer view showing hyperpigmentation streaks along blaschkoid lines|
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| Discussion|| |
Mosaicism refers to the occurrence in an individual of two or more cell population that are karyotypically or genotypically different and yet are derived from a single zygote.  An association of pigmentary anomalies and chromosomal mosaicism has been reported since 1960.  In 1951 Ito reported the first case of hypomelanoses and this was initially referred as incontinentia pigmenti achromians. The term HI was later introduced by Jelinek et al.  Both hypopigmented and hyperpigmented streaks are seen in patients with HI and LWNH. Happle R simplified the nomenclature and proposed the term pigmentary mosaicism to include these different phenotypes. 
The pathogenesis of pigmentary mosaicism is mainly somatic with post zygotic mutation and has been explained by various hypotheses. These include co-migration of genetically different cell populations, functional X-chromosome mosaicism, spreading of X inactivation to autosomes in balanced X autosomal translocations, partial activation or silencing of pigmentary genes by transposons, genetic imprinting and phenotypic reversion. Taibjee et al., in his review has supported the hypothesis that chromosomal abnormalities found in pigmentary mosaicism specifically disrupt expression or function of pigmentary genes. , The genes implicated in pigmentary mosaicism are the P gene with cytogenetic abnormalities involving 15q and p63 gene associated with split hand-foot deformity.  Familial occurrence has been seen in some cases. 
Mosaicism involving the melanocytes shows a particular diversity of cutaneous pattern. The type of pattern depends on the type of cell that is affected and its trajectory of migration and proliferation during embryogenesis. Cutaneous pigmentation presents as hypo-or hyperpigmentation at birth or soon after, along the lines of blaschko (type 1), checker board pattern (type 2), phylloid pattern (type 3), and patchy pattern without midline separation (type 4).  The most common type is along the lines of blaschko presenting as linear steaks or whorls, narrow bands or broad bands. Phylloid pattern is composed of leaf like pattern resembling asymmetrical leaves of begonia, pear shaped areas or areas showing a peculiar oblong configuration. Phylloid pattern has been associated with mosaic trisomy 13, mosaic tetrasomy 5p.  This pattern does not overlap with blaschko's lines. Other skin manifestations seen are cafe-au-lait macules, aplasia cutis, hypohidrosis and accessory nipples.  Hair and nail changes include sparse hair, localized and generalized hypertrichosis and color variations (pepper and salt coloring), ridging of nails, hypoplasia and anonychia. ,
Pigmentary mosaicism has been associated with extracutaneous features. Most common association is neurological deficits like epilepsy, learning difficulties, spasticity, hypotonia, and microcephaly and musculoskeletal features facial dysmorphism, asymmetry of limbs, short stature, syndactyly and kyphoscoliosis. Association of pigmentary anomalies with extracutaneous features are listed in [Table 1]. ,, Pigmentary mosaicism should be differentiated from incontinentia pigmenti, nevus depigmentosus and goltz syndrome. Some consider segmental forms of nevus depigmentosus to be former fruste of pigment mosaicism.
|Table 1: Pigmentary mosaicism associated with extracutaneous abnormalities[9-11] |
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Any child presenting with hypo-or hyperpigmentation or both along the mosaic patterns with systemic abnormalities should be considered under the term pigment mosaicism and investigated for cytogenetic mosaicism. Investigations include karyotyping and skin biopsy for fibroblast culture. Some studies have demonstrated cytogenetic abnormalities in keratinocyte and melanocytes cultures.  Management of pigment mosaicism is multidisciplinary and mainly depends on the underlying systemic abnormalities.
Though we were not able to do fibroblast culture in our case, child had normal karyotyping. Clinically, the child had all the features of pigmentary mosaicism along with multiple extracutaneous abnormalities. All children with pigmentary mosaicism should be investigated in detail for associated systemic features and followed-up regularly, which will help in early management and prevent morbidities.
| References|| |
Happle R. Mosaicism in human skin. Understanding the patterns and mechanisms. Arch Dermatol 1993;129:1460-70.
Ferrier P, Stalder G, Bamatter F, Ferrier S, Buehler E, Klein D. Congenital asymmetry associated with diploid-triploid mosaicism and large satellites. Lancet 1964;1:80-2.
Jelinek JE, Bart RS, Schiff SM. Hypomelanosis of Ito ("incontinentia pigmenti achromians"). Report of three cases and review of the literature. Arch Dermatol 1973;107:596-601.
Taibjee SM, Bennett DC, Moss C. Abnormal pigmentation in hypomelanosis of Ito and pigmentary mosaicism: The role of pigmentary genes. Br J Dermatol 2004;151:269-82.
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Taibjee SM, Hall D, Balderson D, Larkins S, Stubbs T, Moss C. Keratinocyte cytogenetics in 10 patients with pigmentary mosaicism: Identification of one case of trisomy 20 mosaicism confined to keratinocytes. Clin Exp Dermatol 2009;34:823-9.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]