A rare case of progressive cribriform and zosteriform hyperpigmentation

Dear Editor,

Progressive cribriform and zosteriform hyperpigmentation (PCZH) is an asymptomatic mosaic pigmentary anomaly that manifests as linear hyperpigmentation disorder along the Blaschkoid lines with sharp midline cut off. Blaschko's lines are invisible lines representing pathway of ectodermal cell migration and proliferation during fetal development. Many inherited and acquired dermatoses manifests along these lines giving a specific visual pattern to these lines depending upon the area of distribution. We present a rare case of PCZH in a linear pattern in a young adult.

A 28-year-old male patient presented to the dermatology outpatient department with complains of dark colored lesions on right shoulder of 6-year duration. They were insidious in onset and gradually progressive over the last 6 years, with fresh lesions appearing on the anterior aspect of shoulder 1 month back.

The lesions were not associated with any itching, pain, or burning sensation. There was no history of any erythematous or fluid filled lesion prior to the onset of lesion nor was there any antecedent trauma or exposure to drug or irritants. Family history was noncontributory.

Dermatological examination revealed multiple, polysized, well defined, cribriform, and linear hyperpigmented macules over the right shoulder distributed in linear fashion extending from anterior aspect of the shoulder to the posterior aspect (Fig. 1, Fig. 2). No abnormalities were detected on hair, nail, palms, soles, scalp, genital, and mucosal examination.

Fig. 1.

Multiple, polysized, well-defined, cribriform, hyperpigmented macules on shoulder distributed in linear pattern.

Fig. 2.

Multiple, polysized, well-defined, cribriform, hyperpigmented macules on posterior aspect of shoulder distributed in linear pattern.

The basic hematological, biochemical, and urinary investigations were within normal limits. Histopathological examination of the lesional skin revealed increase in basal layer pigmentation (Fig. 3). No nevus cells or melanophages, dermal infiltrate, or pigment incontinence could be visualized (Fig. 4). Histomorphological features were suggestive of PCZH in the background of the appropriate clinical context. The patient was counseled about disorder.

Fig. 3.

Histopathological examination showing increase in basal layer melanization (red arrows) and absence of nevus cells and melanophages (hematoxylin and eosin stain; 400× magnification).

Fig. 4.

Absence of dermal infiltrate or pigmentary incontinence (hematoxylin and eosin stain; 100× magnification).

PCZH was first reported by Rower et al, in 1978 in five patients with pigmentary dermatoses and suggested five diagnostic criteria for this clinicopathologically distinctive pigmentary dermatoses [Table 1].¹

Table 1.

Diagnostic criteria for progressive cribriform and zosteriform hyperpigmentation.

SNo.	Five diagnostic criteria
1.	Uniformly tan cribriform macular pigmentation in a zosteriform distribution
2.	Increase in basal layer melanin along with complete absence of nevus cells on histopathological examination
3.	Absence of history of rash, injury or inflammation to suggest post- inflammatory hyperpigmentation
4.	Onset well after birth with gradual extension
5.	Lack of other associate cutaneous or internal abnormalities

PCZH is a rare asymptomatic pigmentary disorder with unknown incidence and no sex predilection. It appears later in life usually during or after adolescence.^2,3 Trunk is reported to be the most preferential site involved. Clinically, it appears as multiple cribriform hyperpigmented macules in linear or zosteriform pattern along the line of Blaschko. It is usually localized. There is no effective treatment reported so far. Topical therapy like retinoid, emollient, various chemical peels have been tried but no effective results have been observed.²

The exact etiopathogenesis of PCZH remains unknown. Although one school of thought consider somatic mosaicism developing during embryogenesis as the possible etiology yet another concept by Happle postulates clonal migration and proliferation of embryonic melanoblasts along the line of Blaschko, manifesting in a characteristic peculiar cutaneous pattern.^4,5 A few cases of PCZH have been reported to be associated with chromosomal anomaly mainly mosaic trisomy of 7, 14, 18, 20, 48, and X-chromosome mosaicism.⁶

There are certain clinical differential diagnoses that should be kept in mind that manifest as segmental pigmentary dermatoses along the lines of Blaschko [Table 2].^3,6,7 The closest differential linear and whorled nevoid hypermelanosis (LWNH) was first described by Kalter et al in 1988.⁷ It bears almost similar clinical resemblance as PCZH with certain minor differences [Table 3]. LWNH is sporadic and usually spares the mucous membrane, eyes, palms and soles.

Table 2.

Differential diagnosis of progressive cribriform and zosteriform hyperpigmentation.

Ser No.	Segmental pigmentary dermatoses
1.	Linear and whorled nevoid hypermelanosis
2.	Epidermal Nevi (early stage)
3.	Incontientia Pigmenti (third stage)
4.	Focal Dermal Hypoplasia (Goltz syndrome)
5.	X linked reticulate pigmentary anomaly
6.	X linked dominant variant of chondrodysplasia punctate
7.	Café –au-lait macules (McCune-Albright syndrome_
8.	Becker's nevus (non-hypertrichotic variant)
9.	Linear lichen planus
10.	Linear fixed drug eruption

Table 3.

Difference between LWNH and PCZH.

Ser No.	Linear and whorled nevoid hypermelanosis	Progressive cribriform and zosteriform hyperpigmentation
1.	Appears at birth or within first few weeks of birth.2,7 Spreads & stabilizes during the first 2 years of life.	Late onset (during or after adolescence)
2.	Diffuse pattern of hyperpigmented macular lesions in form of streaks and swirls along the Blaschko's line	Localized
3.	Associated with various neurological/cardio vascular/musculoskeletal congenital anomalies8,9	Usually not associated

Many terms like “zebra-like hyperpigmentation in whorls and streaks,” “reticulate zosteriform hyperpigmentation,” “zosteriform lentiginous nevus,” and “reticulate hyperpigmentation of Lijima”, have been used to describe other similar segmental hyperpigmented dermatoses bearing similar clinicopathological findings.¹⁰ Thus, many authors are of the opinion that these possibly are similar dermatoses representing the spectrum of PCZH-LWNH.

Choi et al in their study suggested that PCZH may be considered to be late onset variant of LWNH.² Di Lerni et al also suggested that PCZH should be considered as a part of spectrum of LWNH.¹¹

To the best of our knowledge, there are only a handful of case reports of PCZH in English literature and a few clinicopathological studies till date. It is still considered as a rare pigmentary disorder as it remains primarily under reported probably because of the absence of any associated anomalies and absence of any effective therapy or probably it is misdiagnosed because of its clinical resemblance to other segmental pigmentary dermatoses. Another likely reason for limited number of case report in literature is reporting the cases under different terminology as discussed above.

Thus, in view of perplexity arising due to the surfeit of terminology for these pigmentary disorders bearing similar clinicopathological profile, the authors strongly suggest that there is a need to use a common nomenclature for the spectrum of these pigmentary anomalies to delineate the prevailing confusion.

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The authors have none to declare.