Symmetrical acrokeratoderma: A peculiar entity in China? Clinicopathologic and immunopathologic study of 34 new cases

Symmetrical Acrokeratoderma: A Case Report and Literature Review

The current study explores a case of symmetrical acrokeratoderma, and related literature is reviewed. A 27-year-old male presented with brownish-black plaques distributed symmetrically on the dorsum of the hands and feet for 3 years, and white maceration of the lesions was observed after immersion in water. The patient was diagnosed with symmetrical acrokeratoderma, and Hirudoid ointment was topically administered twice a day for a month. The symptoms were partially alleviated, and the patient is currently under follow-up observation.

Symmetrical acral keratoderma revisited: proposal for a new term, 'pigmented carpotarsal hyperkeratosis'

First reported from Taiwan mistakenly as acral acanthosis nigricans in 1991, pigmented carpotarsal hyperkeratosis or hyperkeratosis nigricans carpi et tarsi displays a peculiar distribution of velvety brown-grey hyperpigmented plaques symmetrically on the flexural side of the wrists and ankles and on the dorsal sides of the hands and feet. A marked epidermal hyperkeratosis with typically mild acanthosis and papillomatosis is observed in histology. Whitish maceration upon perspiration or water exposure, with exacerbation in summer but remission in winter, is common. The association with obesity, endocrine disorders, atopic dermatitis, ichthyosis or malignancy is unknown. Familial occurrence and hereditary patterns are ill-defined. There is preliminary evidence indicating a pathogenic role of missense mutation in the transcription factor 4 gene. Treatment is empirical, with good outcome with topical retinoids and keratolytic agents. Recurrence is common, and long-term prognosis is unclear. To be distinguished are acral acanthosis nigricans, palmoplantar keratoderma of the Nagashima type, palmoplantar keratoderma of the Bothnian type and aquagenic palmoplantar keratoderma. Most reported cases are from Southern China and are predominantly observed in men between the ages of 20 and 40 years. The currently used term 'symmetrical acral keratoderma' is non-specific and misleading and may lead to global unawareness, underreporting or misdiagnosis of this phenomenon. Further genetic and molecular studies are required to clarify its pathogenesis and relation to palmoplantar keratoderma.

Exome sequencing identifies a TCF4 mutation in a Chinese pedigree with symmetrical acral keratoderma

BACKGROUND

Symmetrical acral keratoderma (SAK) is a rare skin disorder and its pathogenesis and inheritability are unknown.

OBJECTIVES

To investigate the inheritance and pathogenesis of SAK.

METHODS

Four SAK cases occurred in a four-generation Chinese family. Exome sequencing identified SNPs with potential SAK-related mutations, and a potentially responsible gene transcription factor 4 (TCF4) was identified. TCF4 was then sequenced in all 11 family members, and pedigree analysis was performed. Histopathology and immunohistochemistry evaluated TCF4 expression in skin lesions. The gene mutation was investigated in human keratinocytes for keratin-related protein expression.

RESULTS

A novel heterozygous missense mutation, c.85C>A (p.Pro29Thr) was found in TCF4. The mutation showed autosomal dominant inheritance and perfectly cosegregated with the SAK phenotype in all family members. In skin lesions, TCF4 was present in the cytoplasm and membranes of the basal layer, the stratum spinosum and the stratum granulosum of the epidermis. The mutant TCF4 induced overexpression of differentiation markers including KRT1, KRT14, loricrin and involucrin.

CONCLUSIONS

A SAK-related gene mutation in TCF4 may function through transcriptional regulation of keratin.

Immunohistochemical evaluation of epidermal proliferation, differentiation and melanocytic density in symmetrical acrokeratoderma

BACKGROUND

Symmetrical acrokeratoderma (SAK) is characterized by brown to black hyperkeratotic patches on acral regions. Although epidermal hyperkeratosis and acanthosis are consistent pathological changes, the nature of epidermal hyperplasia is unknown.

AIM

To evaluate epidermal proliferation and differentiation and melanocytic density in skin lesions of SAK.

METHODS

Expression of keratin 10 (K10), K14, K16, involucrin, filaggrin, Ki-67, and Melan-A was detected by immunohistochemistry in eight patients with SAK, seven patients with ichthyosis vulgaris (IV) and six healthy controls (HCs).

RESULTS

Expression of K14, K16, involucrin and filaggrin was upregulated in patients with SAK compared with patients with IV and the HCs (P < 0.01-0.05), but K10 expression was similar for the three groups (P > 0.05). Numbers of Ki-67+ and Melan-A+ cells were higher in patients with SAK than in patients with IV and the HCs (P < 0.05).

CONCLUSIONS

These results demonstrate that excessive keratinocyte proliferation and abnormal differentiation contribute to epidermal hyperplasia, while melanocytic proliferation is responsible for the pigmented lesions in SAK.

Symmetrical acrokeratoderma: a case series in Indian patients

Abstract

Symmetrical acrokeratoderma is a recently described dermatosis in young adult males of Chinese descent. In this report, we describe a series of five cases of symmetrical acrokeratoderma from India. All 5 patients had asymptomatic, brownish-black plaques distributed symmetrically over dorsum of hand and feet with variable involvement of wrist, flexural surface of forearm, elbow, ankles, shin and knee joint. Palms and soles were characteristically spared. Typically whitish maceration of the lesions was seen after immersing in water. The disease showed exacerbation in hot and humid climate with spontaneous resolution in winter. Histopathological examination showed basket weave hyperkeratosis, irregular acanthosis and mild peri-vascular lymphomononuclear infiltrate. Loosening of the stratum corneum was seen in post-immersion biopsy specimens. Acitretin appeared to provide symptomatic improvement in the short term without any long-term effect on the natural disease course. The genetic and environmental factors involved in disease causation needs to be elucidated in future.

Trial registration

The study was not registered in a trial registry since it was a retrospective analysis of the clinical records and not an interventional/observational study.

New described dermatological disorders

Many advances in dermatology have been made in recent years. In the present review article, newly described disorders from the last six years are presented in detail. We divided these reports into different sections, including syndromes, autoinflammatory diseases, tumors, and unclassified disease. Syndromes included are “circumferential skin creases Kunze type” and “unusual type of pachyonychia congenita or a new syndrome”; autoinflammatory diseases include “chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) syndrome,” “pyoderma gangrenosum, acne, and hidradenitis suppurativa (PASH) syndrome,” and “pyogenic arthritis, pyoderma gangrenosum, acne, and hidradenitis suppurativa (PAPASH) syndrome”; tumors include “acquired reactive digital fibroma,” “onychocytic matricoma and onychocytic carcinoma,” “infundibulocystic nail bed squamous cell carcinoma,” and “acral histiocytic nodules”; unclassified disorders include “saurian papulosis,” “symmetrical acrokeratoderma,” “confetti-like macular atrophy,” and “skin spicules,” “erythema papulosa semicircularis recidivans.”

Ultrastructural study of symmetrical acral keratoderma

BACKGROUND

Symmetrical acral keratoderma is characterized by symmetrical brown hyperkeratotic patches on the acral extremities. However, no studies about its electron microscopic examination have been documented.

OBJECTIVE

Our study was performed to further characterize the histopathology of symmetrical acral keratoderma.

METHODS

A biopsy was taken from brown hyperkeratotic patches on the wrists. Investigative studies included light and electron microscopy.

RESULTS

Light microscopy showed epidermal basket-weave hyperkeratosis and acanthosis. Ultrastructurally, the epidermis was thickened by acanthosis and compact stratum corneum. The horny cell layers were remarkably thicker in clinical affected skin than in adjacent clinically unaffected and healthy skin. The keratin filaments were remarkably clumped or aggregated and irregularly distributed in the horny, spinous, granular and basal cell layers. The tonofilaments formed tight clumps or aggregated at the perinuclear cytoplasm.

CONCLUSION

The main ultrastructural features of symmetrical acral keratoderma were epidermal hyperkeratosis and abnormalities of the keratin filaments and tonofilaments.