Malignant Melanoma Developing in an Area of Palmoplantar Keratoderma (Greither's Disease)

We report a case of malignant melanoma arising on the hyperkeratotic sole of a patient with palmoplantar keratoderma (PPK). Hyperkeratotic lesions were also seen on the dorsa of both hands and feet and the extensor aspects of elbows and knees. The patient's PPK appeared to have been transmitted by an autosomal dominant gene. Histologically, the hyperkeratotic lesions showed acanthosis, marked hyperkeratosis without parakeratosis, and hypergranulosis. All the findings corresponded to those of Greither's disease with malignant melanoma.     

Multiple basal cell carcinomas on phacomatosis pigmentokeratotica

We present a patient with phacomatosis pigmentokeratotica (PPK) who developed several basal cell carcinomas on epidermal nevus lesions in adult life. PPK shows an elevated incidence of development of malignant lesions both on the sebaceous or epidermal nevus component as well as on the nevus spilus one.     

The keratin 16 null phenotype is modestly impacted by genetic strain background in mice

The type I intermediate filament keratin 16 (K16) is constitutively expressed in ectoderm‐derived appendages and is inducibly expressed in the epidermis upon barrier‐compromising challenges. Dominantly acting missense alleles in KRT16 are causative for pachyonychia congenita (PC), a genodermatosis involving debilitating palmoplantar keratoderma (PPK), nail dystrophy, oral lesions and, frequently, alterations in glands and hair. C57Bl/6;Krt16^‐/‐ mice develop oral lesions early after birth and PC‐like PPK lesions as young adults. These PPK lesions have a marked dysregulation of skin barrier‐related genes and innate immunity effectors (eg danger‐associated molecular patterns) and are preceded by oxidative stress secondary to hypoactive Nrf2 signalling. These molecular features are present in PPK lesions of PC patients. Here, we report that all components of the C57Bl/6;Krt16^‐/‐ mouse phenotype occur as well in the FVB strain background, albeit less severely so, a significant observation in the light of variations in the clinical presentation of individuals harbouring disease‐causing mutations in the KRT16 gene.     

Palmoplantar keratoses and Bowen's disease in a Vietnam veteran: Could Agent Blue be implicated?

Agent Blue was an arsenical herbicide used extensively in the Vietnam War. Arsenic is one of the known causes of acquired palmoplantar keratoderma (PPK). The most common manifestation of arsenic exposure in susceptible individuals is bilateral palmoplantar hyperkeratosis. We report a 67‐year‐old man with no known prior exposure to arsenic in the USA or family history of PPK who developed multiple squamous cell carcinoma in situ (SCCIS) and palmoplantar hyperkeratotic lesions beginning 23 years after service in Vietnam. The SCCIS were located on the trunk and extremities in both sun‐exposed and non‐sun‐exposed sites and his palmoplantar lesions were diagnosed concurrently with his SCCIS. He has continued to develop SCCIS since his first visit to our clinic 25 years ago.     

Palmoplantar keratoderma and oral leucoplakia with cutaneous horn of the lips

The inherited palmoplantar keratodermas (PPK) may be associated with a wide variety of other ectodermal abnormalities. The coexistence of PPK and leucoplakia may indicate the increased risk of oesophageal carcinoma in adult life. Cutaneous horn may develop over benign, precancerous, as well as malignant lesions, and frequently may be associated with actinic keratoses and Bowen's disease. On the other hand, the relationship of cutaneous horn and leucoplakia has been the subject of only a single case report. We present a case of PPK and diffuse oral leucokeratosis associated with relapsing cutaneous horn of the lips.     

中国汉族人5家系40例点状掌跖角化病临床及遗传特点分析

目的了解中国汉族人点状掌跖角化病(punctate,palmop lantar keratoderm a)的临床表型和遗传学特点。方法对收集的1例点状掌跖角化病家系进行系统的临床表型和遗传学特点的分析,并将结果与国内报道的其他4例点状掌跖角化病家系进行对比分析。结果①点状掌跖角化病在家系中的传递符合常染色体显性遗传模式;②中国汉族人群中点状掌跖角化病的临床表型特征为点状角化丘疹不规则的分布于掌跖部;③发病年龄跨度较大,可从十几岁至五十岁左右;④大多数家系存在遗传早现现象(antic ipation);⑤同一家系中或不同家系之间患者的表现度(expressivity)可存在明显差异。结论点状掌跖角化病是一种具有高外显率的常染色体显性遗传性皮肤病,临床表型为点状角化丘疹不规则的分布于掌跖部,但不同患者表现度可存在明显差异。     

Diffuse and focal palmoplantar keratoderma can be caused by a keratin 6c mutation

The palmoplantar keratodermas (PPKs) are a large group of genodermatoses comprising nearly 60 genetically distinct diseases. They are characterized by hyperkeratosis on the palms and soles with or without extrapalmoplantar hyperkeratotic lesions. Focal PPK is one of the hallmarks of pachyonychia congenita, a rare autosomal dominant disorder resulting from mutations in the keratin genes KRT6A, KRT6B, KRT16 or KRT17. Recently, in-frame deletion mutations of KRT6C have been identified in three families with focal PPK with slight or no nail changes. We report here a novel KRT6C mutation identified in a Japanese family with PPK with phenotypic heterogeneity, presenting with not only focal but also diffuse hyperkeratosis. The proband had diffuse hyperkeratosis on the soles and small focal hyperkeratoses on the palms, while the two other affected individuals showed focal hyperkeratoses on the soles. All three patients were heterozygotes for c.1414G>A in KRT6C, predicted to result in p.Glu472Lys. These findings strongly suggest that screening of patients with nonepidermolytic diffuse PPK, in whom the pathogenic mutations are yet to be determined, might identify mutations in KRT6C.     

"Nagashima-type" keratosis as a novel entity in the palmoplantar keratoderma category

BACKGROUND: "Nagashima-type" keratosis is characterized by transgressive and nonprogressive palmoplantar keratoderma (PPK) with an autosomal recessive trait. Because its clinical manifestations are similar to but milder than those of mal de Meleda, it was originally described as a mild form of Meleda-type PPK. Since then, about 20 cases have been reported in the Japanese-language literature. However, to our knowledge, no cases have been reported from countries other than Japan, presumably because Nagashima-type PPK was not recognized as a distinct entity. It is essential to describe the characteristics of this disease in the English-language literature. OBSERVATIONS: A 17-year-old boy presented with transgressive, hyperhidrotic, erythematous, and hyperkeratotic lesions on his palms and soles that had developed when he was an infant and had progressed until 2 to 3 years earlier. His family history revealed no similar disorders. The symptoms and clinical course were typical for Nagashima-type PPK. A genetic study was performed to search for a mutation in the SLURP1 gene, which is responsible for mal de Meleda, but no mutations were detected in the exon or intron sites of SLURP1. Conclusion The results of the present genetic study suggest that Nagashima-type keratosis is a novel entity of PPK and is distinct from mal de Meleda.     

Abnormalities of keratinocyte maturation and differentiation in keratosis palmoplantaris striata. Immunohistochemical and ultrastructural study before and during etretinate therapy.

Keratoderma striatum (Brünauer-Fuhs type) with linear keratotic elevations on the palms and small islets (areata form) on the soles is a rare form of palmoplantar keratoderma (PPK). An immunohistochemical and ultrastructural study has been performed to characterize the altered keratinization and maturation patterns in this disease before and during complete clinical remission on therapy with etretinate. Anticytokeratin antibody KL1 showed no significant difference in reaction pattern either between healthy controls and PPK or following therapy. Earlier expression of both filaggrin and involucrin was found in PPK in comparison with the controls. During etretinate therapy the filaggrin pattern returned to normal, whereas the altered involucrin pattern was not influenced. Ultrastructural investigations before treatment revealed tightly packed tonofibrils (TF) and large masses of keratohyalin (KH) granules with abnormal configuration. During therapy the TF and KH granules were reduced in number and size. KH granules now showed frayed borders. Moreover, a transitional cell zone, focal parakeratosis with lipid droplets, and dyskeratotic cells became apparent. The normalization of filaggrin pattern accompanying the clinical remission of these lesions implies a role of this keratinocyte differentiation protein in the pathogenesis of these lesions. Since etretinate is assumed to act at a very late stage of epidermal differentiation, there was no influence on the altered expression of involucrin during etretinate therapy. Despite the clinical remission, fine structural abnormalities persisted, indicating that the deviations from the normal keratinocyte differentiation program in PKK occur very early.     

Hautveränderungen an Händen und Füßen

Background

Palmoplantar dermatoses are common. They can be both functionally debilitating and markedly stigmatize the patient because they are so visible. Dermatoses on the hands and feet often go along with palmoplantar hyperkeratosis. Such palmoplantar keratoses (PPK) can be classified into acquired (non-hereditary) and hereditary (monogenetic) PPK.

Objectives

A considerable proportion of PPK develop on the grounds of gene defects. As these diseases constitute a heterogeneous group of quite uncommon single entities, the treating physician must know when to entertain the diagnosis of a hereditary PPK and which causative genes should be considered.

Methods

We summarize the common causes of acquired and hereditary PPK based on a review of the latest literature.

Results

The most common causes of acquired PPK are inflammatory dermatoses like psoriasis, lichen planus, or hand and feet eczema. Also irritative-toxic (arsenic poisoning, polycyclic aromatic hydrocarbons) and infectious causes of PPK (human papilloma viruses, syphilis, scabies, tuberculosis, mycoses) are not uncommon. Genetically caused PPK may occur isolated, within syndromes or as a paraneoplastic marker. The clinical/histological classification discerns diffuse, focal, or punctuate forms of PPK with and without epidermolysis. A new classification based on the causative gene defect is starting to replace the traditional clinical classification.

Conclusions

Knowledge about the large, but heterogeneous group of hereditary PPK is important to adequately counsel and treat patients and their families.     

Papillon-Lefèvre syndrome and malignant melanoma. A high incidence of melanoma development in Japanese palmoplantar keratoderma patients

Papillon-Lefèvre syndrome (PLS) is a rare autosomal-recessive genodermatosis characterized by palmoplantar hyperkeratosis and severe early-onset periodontitis. The development of malignant cutaneous neoplasms within the hyperkeratotic lesions of the syndrome is quite rare. Here, we report on a 51-year-old Japanese woman with PLS associated with recurrent malignant melanoma (MM). Mutation analysis of the cathepsin C gene revealed that the proband was homozygous for a missense mutation, c.415G-->A, which is predicted to result in the amino acid substitution p.G139R. Including our case, 4 families have been described as having PLS with MM, 3 of which are Japanese, implying a high incidence of melanoma development in Japanese PLS patients. We suggest that hereditary palmoplantar keratoderma (PPK) in Japanese patients might be predisposed to MM. A literature review revealed that in 18 cases of MM-associated PPK, 13 (76%) were Japanese, suggesting a high incidence of MM in Japanese PPK patients. This tendency might be attributable to the high frequency of acral lentiginous melanoma in Japanese subjects, in contrast to a lower frequency of this subtype in Caucasians.     

Improvement of hereditary palmoplantar keratoderma with oral trametinib

We report a child with a past medical history notable for congenital deafness, palmoplantar keratoderma (PPK), and hypothalamic glioma who initiated a MEK inhibitor trametinib for cancer‐directed therapy at 11 years of age and was incidentally noted to have marked improvement in his PPK. Trametinib withdrawal led to worsening in the patient's PPK. We speculate that the patient's PPK improved because of trametinib, given the temporal relationship between trametinib therapy and PPK severity, observed both after introduction and withdrawal of trametinib therapy. The upregulation of MAPK signaling may be involved in the pathogenesis of keratinocyte proliferation in at least some forms of PPK, given that downstream inhibition of MAPK signaling led to an improvement in the patient's PPK.     

Case of punctate palmoplantar keratoderma type I treated with combination of low‐dose oral acitretin and topical salicylic acid and steroid

Palmoplantar keratodermas (PPK) are heterogeneous disorders characterized by abnormal keratinization. Especially, punctate PPK (PPPK), one of the subtypes of hereditary PPK, is a rare punctate keratoderma characterized by tiny “raindrop” keratoses having a tendency to coalesce on the edge of soles, which are exposed to sustained pressure. If typical punctate lesions are confined to the palms and soles and the patient has a family history and late onset, it can be considered as PPPK type I (PPKP1), also called Buschke–Fisher–Brauer disease. The exact etiology of PPPK has not been fully understood. Furthermore, no standardized treatment for PPPK has been established and treatment options are limited. Above all, traditional systemic retinoids have been used in several cases, but dose‐related adverse effects are common. Therefore, combination of low‐dose systemic retinoids and adjuvant topical therapy can be an alternative treatment option for PPPK. Herein, we report a case of PPKP1 treated with combination of low‐dose oral acitretin (10 mg/day) and topical salicylic acid and steroid. Despite low capacity, low‐dose acitretin showed excellent regression of the lesions by combined use of topical ointments. The supplementary topical therapy may be useful in reducing the dose of systemic retinoids and preventing potential toxicity.     

Keratin 16-null mice develop palmoplantar keratoderma, a hallmark feature of pachyonychia congenita and related disorders

Keratin 16 (KRT16 in human, Krt16 in mouse), a type I intermediate filament protein, is constitutively expressed in epithelial appendages and is induced in the epidermis upon wounding and other stressors. Mutations altering the coding sequence of KRT16 cause pachyonychia congenita (PC), a rare autosomal dominant disorder characterized by hypertrophic nail dystrophy, oral leukokeratosis, and palmoplantar keratoderma (PPK). PPK associated with PC is extremely painful and compromises patient mobility, making it the most debilitating PC symptom. In this study, we show that, although inherited in a recessive manner, the inactivation of Krt16 in mice consistently causes oral lesions as well as PPK-like hyperkeratotic calluses on Krt16(-/-) front and hind paws, which severely compromise the animals' ability to walk. Our findings call into question the view that PC-related PPK arises exclusively as a gain-of-function on account of dominantly acting mutated keratins, and highlight the key role of modifiers in the clinical heterogeneity of PC symptoms.     

Punctate porokeratotic keratoderma—its occurrence with internal neoplasia

Punctate porokeratotic keratoderma (PPK) represents a diffuse involvement of palms and soles by multiple, acuminate keratotic papules and plugs, histologically identified by parakeratotic cornoid lamellae. A possible association between PPK and internal malignancy has been previously noted by Herman in 1973². A patient with a 3-month history of PPK is described in which a bronchial carcinoma was recently diagnosed. This association led us to speculate that PPK could be a sign of internal neoplasia, as already established for other forms of palmoplantar keratoderma. We suggest that the presence of an underlying malignancy must be screened for when a diagnosis of PPK is proposed.     

掌跖角化病致病基因研究进展

掌跖角化病是一组以掌跖表皮角化过度为特征的遗传性皮肤病,包含多种表现亚型.近来,掌跖角化病遗传学发病机制的研究取得很大进展,已确定一些不同临床表现型掌跖角化病的致病基因,目前认为,角蛋白1、角蛋白9、角蛋白16、桥粒芯糖蛋白、桥斑蛋白、连接蛋白26、组织蛋白酶C、ARS等基因突变均能导致掌跖角化病的产生,且越来越多新的突变基因位点被发现,推动遗传性掌跖角化病致病基因的研究进程.     

A hypomorphic Egfr allele does not ameliorate the palmoplantar keratoderma caused by SLURP1 deficiency

Mutations in SLURP1, a secreted protein of keratinocytes, cause a palmoplantar keratoderma (PPK) known as mal de Meleda. Slurp1 deficiency in mice faithfully recapitulates the human disease, with increased keratinocyte proliferation and thickening of the epidermis on the volar surface of the paws. There has long been speculation that SLURP1 serves as a ligand for a receptor that regulates keratinocyte growth and differentiation. We were intrigued that mutations leading to increased signalling through the epidermal growth factor receptor (EGFR) cause PPK. Here, we sought to determine whether reducing EGFR signalling would ameliorate the PPK associated with SLURP1 deficiency. To address this issue, we bred Slurp1‐deficient mice that were homozygous for a hypomorphic Egfr allele. The hypomorphic Egfr allele, which leads to reduced EGFR signalling in keratinocytes, did not ameliorate the PPK elicited by SLURP1 deficiency, suggesting that SLURP1 deficiency causes PPK independently (or downstream) from the EGFR pathway.     

Phacomatosis Pigmentokeratotica: A Mosaic RASopathy with Malignant Potential

Phacomatosis pigmentokeratotica (PPK) is a rare epidermal nevus syndrome characterized by the co‐occurrence of a nevus sebaceous arranged along the lines of Blaschko with a speckled lentiginous nevus (SLN). We report a novel KRAS mutation in a patient with a large nevus sebaceous and an SLN who subsequently developed a vaginal botryoid rhabdomyosarcoma, an association not previously reported in the literature. This case expands our knowledge of the genetic basis for phacomatosis, in which mutations in HRAS have been previously described, although this report provides evidence that activating mutations in KRAS or HRAS may cause PPK. This report confirms that PPK is a mosaic RASopathy with malignant potential and raises the question of whether screening for other RAS‐associated malignancies should be performed for all children with PPK.     

Epidermolytic palmoplantar keratoderma of V?rner: is it the most frequent type of hereditary palmoplantar keratoderma?

In a retrospective study, we reevaluated the biopsies that had been obtained, during the past 11 years, from 26 patients presenting with hereditary palmoplantar keratoderma (PPK). Twelve out of 26 biopsies disclosed the histological features of epidermolytic hyperkeratosis, consistent with the diagnosis of epidermolytic PPK of V?rner. A review of the histologically examined cases of the literature revealed a comparable predominance of this hereditary PPK. We conclude that, in contrast to the current opinion, epidermolytic PPK of V?rner represents the most frequent type of hereditary PPK.     

Palmoplantar keratoderma (PPK): acquired and genetic causes of a not so rare disease

Palmoplantar keratodermas (PPK) comprise a heterogeneous group of keratinization disorders with hyperkeratotic thickening of palms and soles. Sporadic or acquired forms of PPKs and genetic or hereditary forms exist. Differentiation between acquired and hereditary forms is essential for adequate treatment and patient counseling. Acquired forms of PPK have many causes. A plethora of mutations in many genes can cause hereditary PPK. In recent years several new causative genes have been identified. Individual PPK may be quite heterogeneous with respect to presentation and associated symptoms. Since the various hereditary PPK – like many other monogenic diseases – exhibit a very low prevalence, making of the correct diagnosis is challenging and often requires a molecular genetic analysis. Knowledge about the large but quite heterogeneous group of hereditary PPK is also important to dissect the molecular mechanisms of epidermal differentiation on palms and soles, ultimately leading to targeted corrective therapies in the future.