|Year : 2021 | Volume
| Issue : 3 | Page : 176-178
Pigmentary mosaicism and extracutaneous defects: a case report of a rare form of twin spotting
Mohamed H.M El-Komy, Eman A EL-Nabarawy, Heba A Abdelkader, Mona R.E Abdel-Halim, Randa S EL-Aguizy
Department of Dermatology, Faculty of Medicine, Cairo University, Cairo, Egypt
|Date of Submission||21-Mar-2020|
|Date of Decision||20-Jul-2020|
|Date of Acceptance||25-Jun-2021|
|Date of Web Publication||24-Nov-2021|
Heba A Abdelkader
Dermatology Department, Kasr Al Aini Hospital, Cairo University, Kasr Al Aini Street, Cairo 11562
Source of Support: None, Conflict of Interest: None
Progressive cribriform and zosteriform hyperpigmentation (PCZH) is an uncommon disorder of pigmentation that is believed to be a result of pigmentary mosaicism. In this report, we describe a child with congenital nevus depigmentosus and low intelligence who later developed PCZH by the age of 5 years.
Keywords: Nevus depigmentosus, pigmentary mosaicism, progressive cribriform and zosteriform hyperpigmentation, segmental pigmentation disorders
|How to cite this article:|
El-Komy MH, EL-Nabarawy EA, Abdelkader HA, Abdel-Halim MR, EL-Aguizy RS. Pigmentary mosaicism and extracutaneous defects: a case report of a rare form of twin spotting. Pigment Int 2021;8:176-8
|How to cite this URL:|
El-Komy MH, EL-Nabarawy EA, Abdelkader HA, Abdel-Halim MR, EL-Aguizy RS. Pigmentary mosaicism and extracutaneous defects: a case report of a rare form of twin spotting. Pigment Int [serial online] 2021 [cited 2022 Jul 1];8:176-8. Available from: https://www.pigmentinternational.com/text.asp?2021/8/3/176/330884
- Pigmentary mosaicism is a collective term for a spectrum of segmental pigmentation disorders.
- Extracutaneous associations should be investigated in cases with combined hyper/hypopigmentation.
| Introduction|| |
Pigmentary mosaicism or pigmentary dysplasia with genetic mosaicism is a collective term for the wide spectrum of segmental pigmentation disorders described in the literature., Extracutaneous associations with these disorders are rarely reported.,,
| Case history|| |
A 5-year-old boy presented with progressively increasing pigmented macules and patches that started 6 months earlier with no history of preceding inflammation or drug intake. Cutaneous examination revealed whorls and streaks of cribriform, brown pigmentation along Lines of Blaschko More Details, affecting the right side of the back and abdomen and the right lower limb [Figure 1]A. Also, there was a hypopigmented patch on the right shoulder that was present since birth, of stationary course [Figure 1]B. There was a history of seizures starting at 3 months of age. No family history of similar conditions was detected.
|Figure 1 (A) Whorls and streaks of cribriform, brown pigmentation along lines of Blaschko affecting the right side of the arm, chest, and abdomen. (B) Hypopigmented patch on the right shoulder of the patient.|
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Developmental assessment showed mental retardation in the form of delayed language development and low intelligence. Echocardiography was normal.
Punch biopsies for histopathology from both lesions were obtained. Hyperpigmented lesions revealed increased basal pigmentation with normal melanocytes (no nevus nests) associated with sparse superficial perivascular lymphohistiocytic infiltrate and melanophages [Figure 2]a, b. The hypopigmented lesion showed patchy reduced to lost basal pigmentation with normal melanocytes (S100 stain) [Figure 2]c, d. Based on clinicopathological correlation, a diagnosis of progressive cribriform and zosteriform hyperpigmentation (PCZH) associated with nevus depigmentosus (ND) was made.
|Figure 2 Photomicrograph showing (a) Pigmented basal layer, sparse superficial perivascular infiltrate with melanophages, and absent nests of melanocytes (hematoxylin and eosin [H&E], original magnification ×100). (b) Melanophages in the dermal infiltrate and pigmented basal cell layer (H&E, original magnification ×400). (c) Patchy reduction in basal pigmentation (H&E, original magnification ×100). (d) Intact melanocytes along the basal cell layer (S100, original magnification ×100).|
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| Discussion|| |
In 1978, Rower et al., proposed a number of criteria for the diagnosis of PCZH, including uniformly tan cribriform macular pigmentation in a zosteriform distribution; starting well after birth with no history of trauma or inflammation; mild increase in melanin pigment in the basal cell layer and complete absence of nevus cells histopathologically; and absence of other associated cutaneous or internal abnormalities.
Di Lernia suggested that PCZH is a part of the spectrum of linear and whorled nevoid hypermelanosis (LWNH) as there was no difference between the two disorders clinically and histopathologically apart from age of onset. They also proposed the terms “Diffuse LWNH” for previous reported cases of LWNH and “Localized-form” for PCZH.
The ND is a rare congenital pigmentary disorder that may rarely have systemic associations. It had been proposed that ND is a form of cutaneous mosaicism wherein an altered clone of melanocyte has a decreased ability to synthesize melanin and transport to keratinocytes.
Taking into consideration, the observations made by Taibjee et al., that of Ito hypomelanosis (HI) and LWNH represent pigmentary mosaicism. This appears also true for localized and segmental forms of pigmentary disorders as PCZH and localized ND observed in our patient.
The frequency of extracutaneous findings in association with segmental pigmentary disorders is reported to be low in multiple reviews.,,
A review of literature for pigmentary mosaicism was conducted by Kromann and his colleagues in 2018. They found a combination of hyperpigmentation and hypopigmentation in 7% of a total of 651 published patients. Extracutaneous involvement among such cases is exceedingly high, where 40 of the 48 cases previously described of coexistent hyper- and hypopigmentation were associated with extracutaneous manifestations. Developmental delay and seizures were reported in 54% and 37% of patients with extracutaneous manifestations, respectively. They recommend using the term pigmentary mosaicism instead of the multiple confusing terms described in literature, for example, LWNH, HI, incontinentia pigmenti achromians, ND, achromic nevus, and segmental pigmentation disorder. Happle et al. proposed the term “Cutis tricolor” for patients with coexisting hyper- and hypopigmented skin. They explained those findings by the genetic mechanism of twin spotting. For a gene locus controlling skin pigmentation, there are two alleles balancing each other leading to intermediate pigment production. When a somatic recombination event occurs during early embryo development, the result will be two daughter cells homozygous for either allele which are the stem cells for the pigmentary twin spots.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]