An unusual presentation of a progressive zosteriform macular pigmented lesion.

Abstract

Dear Editor: Rower et al.1 defined progressive cribriform and zosteriform hyperpigmentation (PCZH) in 1978 as a disease that fulfils the following criteria: 1) cribriform pigmented macules that form a zosteriform distribution, 2) no history of skin disease or injury that would suggest postinflammatory hyperpigmentation, 3) an onset that arises well after birth, followed by gradual extension, 4) an onset that has no association with other skin diseases or internal abnormalities, and 5) characterized histologically by a mild increase in melanin pigment in the basal layer without nevus cells. In 1980, Simoes and Piva2 described the progressive zosteriform macular pigmented lesion (PZMPL) as a chronic pigmentary dermatosis with similar clinical findings to PCZH. Although PZMPL is not completely understood, it is thought to be a variant of PCZH. PZMPL is distinguishable from PCZH because it presents with pruritus as a prodromal symptom and is characterized clinically by its abrupt spreading and histologically by pigmentary incontinence. A 12-year-old boy presented with congenital brown pigmented skin lesions along Blaschko's lines on the right side of his trunk and upper extremities (Fig. 1). He complained of occasional mild itching. The lesions had recently extended to the left side across the midline. The histopathological findings showed increased levels of melanin pigment in the basal layer and focal pigmentary incontinence in the upper dermis (Fig. 2). Fig. 1 Linear macular pigmented lesion extending from right to left, across the midline of the trunk. Fig. 2 (A) Increased pigmentation in the basal layer and some melanophages in the upper dermis (H&E, ×400), (B) Immunohistochemical staining is positive for Fontana-Masson (×200). The etiology of PZMPL is unknown. It has been speculated that its pathogenesis might be the same as other diseases that develop along Blaschko's lines. Among the many inherited and some acquired skin conditions that develop along Blaschko's lines, sporadic cases like the present one are often explained as inherited mosaicism. Further studies of similar cases are necessary to determine the pathogenesis of the disease. PCZH arises after birth and follows the dermatomes. In terms of its hyperpigmentation and its asymptomatic nature, the case described in this report seems to align with the characteristics of PCZH, but the cribriform arrangement of small scattered macules is one particular characteristic of PCZH that differs from the extensive patches seen in the present case3. The similarities of PZMPL to the present case include the presence of extensive plaques along Blaschko's lines and macules that converged and became bigger. Simoes and Piva2 reported that PZMPL is accompanied by itching, and that the condition remains static for a certain period of time followed by an abrupt enlargement of the lesions, which is similar to the present case. The histological features, the extensive patches along Blaschko's lines, and the abrupt enlargement of the skin lesions suggested a diagnosis of PZMPL. Since the first case of PZMPL described by Simoes and Piva2 three more cases have been investigated, including the present one. Given that the diagnosis of PZMPL is not well established, we hope that this case report contributes towards elucidating a standard definition, the pathophysiology, and the progression of PZMPL. We recommend that dermatologists consider this disease when they encounter patients with chronic hyperpigmented dermatoses.