Dermatology Online Journal

Striate palmoplantar keratoderma (Brunauer-Fohs-Siemens syndrome)
Jennifer Bragg MD, Carina Rizzo MD, Stephanie Mengden MD
Dermatology Online Journal 14 (5): 26

Department of Dermatology, New York University

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Abstract

A 64-year-old man presented with focal hyperkeratotic plaques on the fingers, palms, and soles. Histopathologic and electron microscopic results were consistent with striate palmoplantar keratoderma. Treatment with topical keratolytics was unsuccessful. Striate palmoplantar keratoderma or Brunauer-Fohs-Siemens syndrome is an autosomal dominant condition that presents with linear hyperkeratosis on the palms and fingers and focal plaques on the plantar aspects of the feet. Histopathologic features include hyperkeratosis, hypergranulosis, and acanthosis with no epidermolysis. Electron microscopic examination shows diminished desmosomes, clumped keratin filaments, and enlarged keratohyalin granules. The syndrome has been linked to mutations in desmoglein 1, desmoplakin, and keratin 1. Treatment may include keratolytics, oral retinoids, and surgical debridement.

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Clinical synopsis

The patient presented to the New York Campus of the Veterans Affairs New York Harbor Healthcare System for treatment of painful lesions on his palms and soles, which first developed when he joined the United States Army as a teenager and have progressively worsened since that time. No family members have similar lesions. The patient has no known cardiac disease. Treatment has included topical urea, lactic acid, and salicylic acid as well as surgical debridement by a podiatrist, but the patient reports minimal improvement with any of these modalities.

Physical Examination

Hyperkeratotic plaques were present over the plantar aspects of the heels without extension onto the dorsal aspects of the feet. Small, round, well-demarcated plaques were noted on the anterior portions of the plantar aspects of the feet. Linear bands of hyperkeratosis were present on the volar third and fifth fingers bilaterally, and a punctate hyperkeratotic papule was noted along one palmar crease on the left. No nail or hair abnormalities were present.

Figure 1	Figure 2

Figure 3

A complete blood count, basic metabolic panel, and liver function tests were normal

Histopathology

There is marked orthohyperkeratosis and mild focal parakeratosis of the cornified layer. There is prominent hypergranulosis within a papillated and acanthotic epidermis.

Comment

The inherited palmoplantar keratodermas are characterized by epidermal thickening of the palms and soles that can be classified as diffuse, punctate, or local. These disorders can be further categorized into simple, complex, and syndromic forms and epidermolytic or nonepidermolytic variants [1]. Striate palmoplantar keratoderma (PPK), which also is known as Brunauer-Fohs-Siemens syndrome, is considered a simple, focal nonepidermolytic PPK. It is an autosomal dominant condition due to haploinsufficiency; one active allele instead of two results in decreased production of the involved protein [2].

Striate PPK usually presents in early childhood with areas of hyperkeratosis on the plantar aspect of the feet with no transgrediens. Linear, hyperkeratotic plaques on the volar fingers and palms may develop later and are often exacerbated by manual labor. Hyperkeratotic plaques also may be observed on the elbows and knees. Single case reports have documented an association with brachyphalangia [3]; pili torti, hypohidrosis, hypodontia, and hypoacusis [4]; left ventricular dilated cardiomyopathy and woolly hair [5]; acral malignant melanoma [6]; and hypotrichosis, acro-osteolysis, and periodontitis [7].

Histopathologic features are characterized by hyperkeratosis, hypergranulosis, and acanthosis with no epidermolysis. Granular and filamentous material that represents clumped keratin filaments also may be observed. Electron microscopic examination shows desmosomes that are decreased in number and/or size, keratin filament aggregates, and enlarged malformed keratohyalin granules [8].

The pathogenesis has been linked to mutations in the genes for desmoglein 1 (type I striate PPK), desmoplakin (type II striate PPK), and keratin 1 [2, 9, 10, 11]. Desmoglein 1 and desmoplakin are components of the desmosome. Desmoglein 1 is a member of the cadherin family of transmembrane proteins that link desmosomal plaques in adjacent cells. Desmoplakin is a member of the plakin family of intracellular proteins that link the membrane cadherins to the keratin intermediate filaments in the cytoplasm. Keratin 1 is a type II basic keratin usually found in association with keratin 10 in the suprabasal layer. Additional desmosomal components and keratins are altered in striate PPK, which suggests that one abnormality in the desmosomal and intermediate filament network impacts the entire system. These observations suggest that a structural disruption of desmosomes may affect their signaling role in the regulation of epidermal proliferation and differentiation [12].

Treatment for keratodermas is only moderately successful and is based on anecdotal evidence. Options include topical keratolytics, surgical debridement, and oral retinoids. Treatment with bath PUVA photochemotherapy has also been reported [13].

References

1. Hatsell S, Kelsell D. The diffuse palmoplantar keratodermas. Acta Dermatovenereol APA 2000;9:47

2. Whittock NV, et al. Frameshift mutation in the V2 domain of keratin 1 causes the striate form of palmoplantar keratoderma. J Invest Dermatol 2002;118:838

3. Tursen U, et al. Concordance of striate palmoplantar keratoderma and brachyphalangia in monozygous twins. J Eur Acad Dermatol Venereol 2006;20:1343

4. Egelund E, Frentz G. A case of hyperkeratosis palmoplantaris striata combined with pili torti, hypohidrosis, hypodontia and hypoacusis. Acta Otolaryngol 1982;94:571

5. Norgett EE, et al. Early death from cardiomyopathy in a family with autosomal dominant striate palmoplantar keratoderma and woolly hair associated with a novel insertion mutation in desmoplakin. J Invest Dermatol 2006;126:1651

6. Rubegni P, et al. Acral malignant melanoma and striated palmoplantar keratoderma (Brunauer-Fohs-Siemens syndrome): a fortuitous association? Derm Surg 2004;30:1539

7. Van Steensel MAM, et al. New syndrome of hypotrichosis, striate palmoplantar keratoderma, acro-osteolysis and periodontitis not due to mutations in cathepsin C. Br J Dermatol 2002;147:575

8. Fartasch M, et al. Abnormalities of keratinocyte maturation and differentiation in keratosis palmoplantaris striata. Am J Dermatopathol 1990;12:275

9. Hennies HC, et al. Localization of a locus for the striated form of palmoplantar keratoderma to chromosome 18q near the desmosomal cadherin gene cluster. Hum Mol Genet 1995;4:1015

10. Fickman L, et al. N-terminal deletion in a desmosomal cadherin causes the autosomal dominant skin disease striate palmoplantar keratoderma. Hum Mol Genet 1999;8:971

11. Armstrong DK, et al. Haploinsufficiency of desmoplakin causes a striate subtype of palmoplantar keratoderma. Hum Mol Genet 1999;8:143

12. Wan H, et al. Striate palmoplantar keratoderma arising from desmoplakin and desmoglein 1 mutations is associated with contrasting perturbations of desmosomes and the keratin filament network. Br J Dermatol 2004;150:878

13. Kaskel, P, et al. PUVA-bath photochemotherapy for congenital palmoplantar keratoderma in an 11-year-old girl. Br J Dermatol 2000;143: 464

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