Melanoma in skin affected with keratoderma palmoplantaris hereditaria (Mal de Meleda): Treatment with excision and grafting

[Acral melanoma in a patient with hereditary keratoderma of the palms and soles (mal de Meleda): A chance association?]

INTRODUCTION

Development of acral malignant melanoma in Mal de Meleda is highly unusual. As far as we could ascertain, to date, only 10 previous cases have been published. Herein, we report a new case.

OBSERVATION

A 64-year-old Algerian man was followed for familial Mal de Meleda. The diagnosis was based on clinical presentation as he had a non-syndromic hereditary foul-smelling and yellowish palmoplantar keratoderma transgrediens. After the failure of acitretin, which had not prevented retractile and mutilating progression of the palmoplantar keratoderma, he had undergone surgery with graft excision of both palms. At the age of 59 years, he presented a tumor on the dorsal aspect of the 1^st phalanx of the 3^rd finger of the right hand in a non-grafted area. The diagnosis of acral melanoma was confirmed histologically. The radiological findings showed a specific homolateral axillary adenopathy. He underwent digital amputation of the 3^rd finger, with lymph node dissection and chemotherapy involving dacarbazine. Follow-up at 5 years showed complete remission of the melanoma.

DISCUSSION

Mal de Meleda is a hereditary palmoplantar keratoderma due to mutation of the SLURP1 gene. Clinical diagnosis is based on the typical phenotype in adulthood. The occurrence of acral melanoma, which is a rare form of melanoma (1 to 7%), especially in the fingers, together with an unusual palmoplantar keratoderma in a subject of type IV phototype does not appear to be a chance event. This association seems to be the outcome of immune dysregulation rather than of chronic inflammation.

Nagashima-type palmoplantar keratosis in a Chinese Han population

Nagashima-type palmoplantar keratosis (NPPK) is an autosomal recessive form of palmoplantar keratoderma (PPK), which is caused by mutations in the SERPINB7 gene. NPPK has only been reported in Japanese and Chinese populations. The present study was conducted on 12 unrelated Chinese patients who were clinically predicted to suffer from NPPK. Mutation screening was performed by direct sequencing of the entire coding regions of SERPINB7, SLURP1, AQP5, CSTA, KRT1 and KRT9 genes. Direct sequencing of SERPINB7 revealed five homozygous founder mutations (c.796C>T) and four compound heterozygous mutations in nine patients, including one novel mutation (c.122_127delTGGTCC). Nine out of the 12 patients were diagnosed with NPPK due to SERPINB7 pathogenic mutations, and the results expanded the known mutation spectrum of NPPK. Taking the other seven reported Chinese patients, who had been definitively diagnosed with NPPK by genetic testing, into account, the present study further demonstrated that NPPK is a common entity in Mainland China, and c.796C>T is the most prevalent mutation and exerts a founder effect. Furthermore, the NPPK cases described in the current study presented a consistently mild phenotype, as compared with the degrees of phenotypic variability associated with other types of relatively severe PPK, including Mal de Meleda and Olmsted syndrome.

Mal de Meleda: A Focused Review

Mal de Meleda is a rare autosomal recessive palmoplantar keratoderma (PPK) disease with an estimated prevalence of 1:100,000. Clinically, the onset of the disease is typically soon after birth and features a transgrediens (plantar surface progressing to dorsal surface) and progrediens (worsening with age) pattern of hyperkeratosis of the palms and soles. The disease can feature other potentially disfiguring effects on the hands and feet that can severely impact function. Histologically, the lesions show hyperkeratosis and acanthosis without epidermolysis in the epidermis, accompanied by perivascular lymphocytic infiltrate in the dermis. Secreted LY6/urokinase-type plasminogen activator receptor (uPAR)-related protein-1 (SLURP-1) genetic mutations are implicated in Mal de Meleda. SLURP-1 is involved in mediation of inflammation as well as keratinocyte apoptosis regulation. Because the disease is so rare, there are no set guidelines for management, but the accepted approach tends to include oral acitretin plus topical keratolytic therapy. Genetic counseling should also be offered. This focused review highlights the clinical and histological features, differential diagnoses, genetic background, and the current thoughts on management of Mal de Meleda.

Particular Mal de Meleda phenotypes in Tunisia and mutations founder effect in the Mediterranean region

Mal de Meleda (MDM) is a rare, autosomal recessive form of palmoplantar keratoderma. It is characterized by erythema and hyperkeratosis of the palms and soles that progressively extend to the dorsal surface of the hands and feet. It is caused by mutations in SLURP-1 gene encoding for secreted mammalian Ly-6/uPAR-related protein 1 (SLURP-1). We performed mutational analysis by direct sequencing of SLURP-1 gene in order to identify the genetic defect in three unrelated families (families MDM-12, MDM-13, and MDM-14) variably affected with transgressive palmoplantar keratoderma. A spectrum of clinical presentations with variable features has been observed from the pronounced to the transparent hyperkeratosis. We identified the 82delT frame shift mutation in the SLURP-1 gene in both families MDM-12 and MDM-13 and the missense variation p.Cys99Tyr in family MDM-14. To date, the 82delT variation is the most frequent cause of MDM in the world which is in favour of a recurrent molecular defect. The p.Cys99Tyr variation is only described in Tunisian families making evidence of founder effect mutation of likely Tunisian origin. Our patients presented with very severe to relatively mild phenotypes, including multiple keratolytic pits observed for one patient in the hyperkeratotic area which was not previously reported. The phenotypic variability may reflect the influence of additional factors on disease characteristics. This report further expands the spectrum of clinical phenotypes associated with mutations in SLURP1 in the Mediterranean population.