Recurring HRAS mutation G12S in Dutch patients with Costello syndrome

Costello syndrome (CS) is a rare multiple congenital anomaly/mental retardation syndrome characterized by coarse face, loose skin and cardiomyopathy. It is often associated with benign and malignant tumors. Several groups have now demonstrated that CS is caused by recurring mutations in the HRAS gene in different ethnic groups. Here, we describe three unrelated Dutch patients and show that they all have the same mutation, G12S, in HRAS. To our knowledge, our patients are the first Dutch to be analysed. The syndrome seems to be genetically homogeneous. We discuss the pertinent nosology of the syndrome.     

Woolly hair nevus caused by somatic mutation and Costello syndrome caused by germline mutation in HRAS: Consider parental mosaicism in prenatal counseling

Germline mutations in HRAS cause Costello syndrome (CS), while mosaic mutations in HRAS show a variability of phenotypes, ranging from mild features such as keratinocytic epidermal nevus (KEN), sebaceous nevus (SN), woolly hair nevus (WHN) with KEN, to severe manifestations of CS with cutis laxa. We report two individuals. The first was a 2-year-old boy with woolly hair nevus (WHN) without any other cutaneous involvement, in whom somatic HRAS mutation (c.34G>A; p.Gly12Ser) was identified in his affected scalp and hair follicle specimens. This is the first reported WHN type 1 (no cutaneous involvement) patient caused by somatic HRAS mutation. The other individual was a 12-year-old girl with CS caused by germline HRAS mutation (c.34G>A), that manifested with coarse face, palmoplantar keratoderma, deep palmar and plantar creases, hyperpigmented patches, asymmetry and deformity of lower limbs, atopic dermatitis, as well as mental retardation. Of note, a linear hyperpigmented plaque was observed in her father’s lumbosacral region. Although the father refused to provide semen and skin tissue for further examination, this reminds us of possible mosaicism in parents of individuals with germline de novo HRAS mutation and underlines the importance of parental evaluation for prenatal counseling.     

Secondary neoplasms arising from nevus sebaceus: A retrospective study of 450 cases in Taiwan

Nevus sebaceus is frequently associated with the development of secondary neoplasms. Incidences of malignant transformation vary among different reports and few data is available regarding Asian populations. We aimed to determine the characteristics of secondary tumors developing from nevus sebaceus in a Taiwanese population and to review the published work. Patients with clinically and histologically confirmed nevus sebaceus were identified from 1992 to 2012 in a medical center. Among the 450 cases of nevus sebaceus, 38 secondary neoplasms were noted, accounting for 8.5% of all cases. Benign tumors represented more than 80% of all tumors. Syringocystadenoma papilliferum (2.7%) was the most common benign tumor, followed by trichoblastoma (1.6%) and trichilemmoma (1.6%) whereas basal cell carcinoma (0.9%) was the most frequent malignant tumor on nevus sebaceus and its clinical features were not typical. All the malignant tumors on nevus sebaceus were noted only in adulthood and the mean age of those with basal cell carcinoma was significantly older than that of trichoblastoma (P = 0.028). Our study concludes that malignant transformation is rare in nevus sebaceus and occurs uniquely in adulthood. On the basis of the findings, prophylactic excision of nevus sebaceus can be elective during childhood but is strongly advocated at puberty due to the increased risk of malignant transformation with time.     

Trichoblastoma,syringocystadenoma papilliferum,desmoplastic trichilemmoma and tumor of the follicular infundibulum with signet‐ring cells,all arising in nevus sebaceus

Herein, we describe a 63‐year‐old male with multiple tumors arising within a nevus sebaceus on the posterior scalp. On histopathologic examination, four distinct tumors were identified: trichoblastoma, syringocystadenoma papilliferum, desmoplastic trichilemmoma and tumor of the follicular infundibulum (TFI). Within the TFI component of the nevus sebaceus, there was intracytoplasmic accumulation of eosinophilic keratin, as shown on pancytokeratin‐stained sections, imparting a signet‐ring appearance to the cells. To our knowledge, this is the first report of signet‐ring cells arising within a TFI occurring in a nevus sebaceus. We discuss this case as well as review the literature on multiple tumors arising within nevus sebaceus and signet‐ring cell changes in primary cutaneous tumors.     

Trichoblastomas with Merkel cell proliferation in nevi sebacei in Schimmelpenning‐Feuerstein‐Mims syndrome – Histological differentiation between trichoblastomas and basal cell carcinomas

The hallmark of Schimmelpenning‐Feuerstein‐Mims syndrome (SFMS) is a systematized nevus sebaceous that follows Blaschko lines and usually involves the face. It represents a rare congenital nevus syndrome with alterations of skin, bones, CNS, eyes and heart. Nevi sebacei can proliferate and develop into epithelial tumors like trichoblastoma, syringocystadenoma and basal cell carcinoma. The histological differentiation between basal cell carcinoma and trichoblastoma is difficult. We present an adult woman with SFMS who was followed by multiple specialties since birth without the correct diagnosis being made. She was referred to us with the diagnosis of multiple basal cell carcinomas of head and face. Our diagnosis of systematized nevus sebaceus was crucial for the correct classification of SFMS. We identified multiple trichoblastomas in the nevi sebacei and could exclude basal cell carcinomas. The essential clue was the detection of multiple Merkel cells within the epidermal layer by cytokeratin 20 staining.     

Cutaneous involvement of pre‐existing Rosai–Dorfman disease via post‐herpetic isotopic response

We report the case of a patient with a long‐standing history of extranodal, sinus histiocytosis with massive lymphadenopathy (Rosai–Dorfman disease) and no evidence of original cutaneous involvement as well as a history of herpes zoster of the left flank with post‐herpetic neuralgia who went on to develop multiple, round‐to‐oval, red‐brown, atrophic macules and thin papules at the sites of herpes zoster scars on the left flank. Histopathology showed a dense nodular infiltrate of lymphocytes with some plasma cells and numerous large pale‐staining histiocytes (S100+/CD68+), consistent with Rosai–Dorfman disease. This case showed exclusively cutaneous involvement, as demonstrated by otherwise normal physical examination, laboratory evaluation and imaging. This is the second reported case of Rosai–Dorfman disease occurring at the site of zoster scars, and to our knowledge this represents the first case report of cutaneous involvement of pre‐existing Rosai–Dorfman disease via post‐herpetic isotopic response (Wolf's isotopic response).     

Mosaic‐activating FGFR2 mutation in two fetuses with papillomatous pedunculated sebaceous naevus

Papillomatous pedunculated sebaceous naevus (PPSN) has been described as a subtype of sebaceous naevus (SN), typically affecting the scalp and face. In contrast with Schimmelpenning syndrome, no cerebral, ocular or skeletal anomalies have hitherto been reported. We report two unrelated fetuses with PPSN, one with large pink exophytic tumours, the other with minor features but similar microscopic findings. We performed whole‐exome sequencing in affected skin tissue from fetus 1, which identified a postzygotic de novo FGFR2 c.1144T>C (p.Cys382Arg) mutation in 34·6% of reads which was absent in the parents’ blood. Targeted deep sequencing of FGFR2 confirmed its mosaic status in additional affected skin from fetus 1, and identified the same substitution in 26% of reads in affected skin from fetus 2. FGFR2 p.Cys382Arg is a known somatic driver mutation in human cancer, previously reported to result in activation of RAS signalling. A similar paralogous missense mutation in the transmembrane domain of FGFR3 (p.Gly380Arg) has been reported in keratinocytic epidermal naevi. Our findings define a distinct clinical and molecular subgroup of SN, beside HRAS or KRAS‐related SN, and expand the spectrum of mosaic skin conditions associated with receptor tyrosine kinase mutations.     

Low‐dose acitretin in Papillon–Lefèvre syndrome: treatment and 1‐year follow‐up

The Papillon–Lefèvre syndrome (PLS) is a rare, autosomal recessive disease that manifests with palmoplantar keratoderma and destructive periodontitis resulting in early onset periodontal breakdown in deciduous and permanent dentition. Management of this condition is difficult. Here we report one 11‐year‐old consanguineous Muslim boy suffering from PLS. After failing to get any benefit from methotrexate, three cycles of acitretin, each for 2 months, were given 1 month apart. In each cycle, acitretin (25 mg) was given every other day. At the end of the third cycle, treatment was stopped for 4 months to observe the extent of relapse. Thereafter, acitretin (25 mg) was given twice weekly for 4 months and then the patient was followed up for 1 year. Treatment with acitretin resulted in excellent improvement of periodontitis, increase in the alveolar bone height, and periodontal attachment. Improvement remained stable at the end of 1‐year follow‐up. There was excellent (>75%) improvement in keratoderma at the end of active therapy. Mild worsening of palmoplantar keratoderma was noticed whenever the drug was stopped. It improved when the drug was restarted. Other areas remained stable. At the end of 1‐year follow‐up, good improvement (50%) in palmoplantar keratoderma was achieved.     

Successful treatment with narrow‐band UVB therapy for a case of generalized Hailey–Hailey disease with a novel splice‐site mutation in ATP2C1 gene

Hailey–Hailey disease (HHD) is a rare autosomal dominant disorder characterized by development of recurrent blisters, erosions, and crustations in the intertriginous areas. The treatment of HHD is often challenging, and various methods have been tried. We report here a case of a 45‐year‐old woman with a generalized form of HHD that was dramatically improved and well controlled by narrow‐band ultraviolet B phototherapy.     

A new COL3A1 mutation in Ehlers–Danlos syndrome type IV

The vascular type of the Ehlers–Danlos syndrome (Ehlers–Danlos syndrome type IV, EDS IV; OMIM #130050) is a rare connective tissue disorder with autosomal dominant transmission caused by mutations in the COL3A1 gene resulting in increased fragility of connective tissue with arterial, intestinal, and uterine ruptures and premature death. We present a 28‐year‐old female who in addition to typical EDS IV symptoms had severe peripheral artery occlusive disease (PAOD) and subtotal stenosis of the abdominal aorta. COL3A1 sequencing resulted in detection of an as yet undescribed mutation in exon 36 at position 2465 leading to a nucleotide replacement (c.2465G>C; p.G822A). Ultrastructural analysis of a skin biopsy revealed abnormal morphology and distribution of dermal collagen fibres. We conclude that PAOD is a possible manifestation of EDS IV and that further research is required to define its true prevalence among patients with EDS IV and its molecular pathology including genotype–phenotype correlation.     

Histopathological insights into hair loss in Cronkhite–Canada syndrome: Diffuse anagen‐telogen conversion precedes clinical hair loss progression

Cronkhite–Canada syndrome (CCS) is a rare disorder characterised by gastrointestinal polyposis and ectodermal changes, represented by extensive alopecia. Detailed histopathological investigations of alopecic lesions in two female CCS patients with severe hair loss revealed a marked increase in telogen hair follicles with no sign of loss or of the minaturisation or atrophy of hair follicle structures and the absence of inflammatory change, despite severe inflammation in the gastrointestinal tract. These findings suggested that hair regrowth can be expected without systemic corticosteroids, if they are not necessary for treatment of the gastrointestinal tract, and that anagen‐telogen transition is an early event preceding clinical hair loss in CCS.     

A novel missense mutation of the CYLD gene identified in a Hungarian family with Brooke–Spiegler syndrome

Brooke–Spiegler syndrome (BSS; OMIM 605041) is an autosomal dominant disease characterized by skin appendage tumors due to mutations in the cylindromatosis gene (CYLD). We investigated a Hungarian BSS pedigree with two affected members, father and daughter. Direct sequencing demonstrated a novel missense mutation (c.2613C>G; p.His871Gln) in exon 19 within the ubiquitin‐specific protease domain of the encoded protein. We performed preliminary analysis to reveal the functional role of this novel mutation. Our data suggest that this novel CYLD mutation leads to increased ubiquitination of NEMO through influencing deubiquitinating activity of the CYLD protein and thus may result in enhanced NF‐κB signalling.     

Ethosuximide‐induced Stevens–Johnson syndrome: Beneficial effect of early intervention with high‐dose corticosteroid therapy

We report two rare cases of childhood epilepsy patients who developed ethosuximide‐induced Stevens–Johnson syndrome (SJS). Unlike typical SJS, the initial eruption of both patients presented well‐demarcated, infiltrating firm papules mainly on the cheeks and the extensor aspects of the arms (case 1), and multiple vesicles on the soles and oral aphthosis (case 2), which closely mimicked viral exanthema. We diagnosed both patients with ethosuximide‐induced SJS, based on the dosing period and the positive results of drug‐induced lymphocyte stimulation test. Systemic corticosteroids are usually selected as a standard therapy for SJS, despite controversial results regarding their effectiveness. In case 1, an i.v. pulse therapy of methylprednisolone (30 mg/kg, 3 days consecutively) was initiated on day 7 from the onset of illness, and an i.v. immunoglobulin (400 mg/kg, 5 days consecutively) was added the following day. In case 2, an i.v. prednisone treatment (1 mg/kg, for 1 week) was initiated on day 4 from the onset. Eventually, the early therapeutic interventions resulted in good outcomes in both patients.     

Review of the current medical literature and assessment of current utilization patterns regarding mismatch repair protein immunohistochemistry in cutaneous Muir–Torre syndrome‐associated neoplasms

Muir–Torre syndrome is a clinical variant of Lynch syndrome defined by the synchronous or metachronous occurrence of at least one sebaceous neoplasm and at least one Lynch syndrome‐related internal cancer. Although screening guidelines for patients with colorectal carcinomas have been established, screening guidelines for cutaneous Muir–Torre associated neoplasms are not currently available. As such, we reviewed the current evidence for the use of MLH1, MSH2, MSH6 and PMS2 immunohistochemistry when cutaneous Muir–Torre associated neoplasms are encountered. We identified weak to moderate support overall for the global use of these assays, with some evidence suggesting a tailored approach using clinical parameters as an adjunct. We also assessed the current utilization patterns of attendees of the American Society of Dermatopathology Annual Meeting (Chicago, 2016). We found that 91% of respondents utilize mismatch repair immunohistochemistry, with the majority utilizing these tests only when requested by the submitting clinician.     

Tenascin‐X deficiency and Ehlers–Danlos syndrome: a case report and review of the literature

Tenascin‐X is a large extracellular matrix glycoprotein that is widely distributed within connective tissues and is associated with an autosomal recessive type of Ehlers–Danlos syndrome (EDS). Tenascin‐X represents the first EDS susceptibility gene that does not code for a fibrillar collagen or collagen‐processing enzyme. We describe a paediatric case of tenascin‐X deficiency and review the literature.     

Klippel–Trenaunay syndrome belongs to the PIK3CA‐related overgrowth spectrum (PROS)

Klippel–Trenaunay syndrome (KTS), originally described as a triad of cutaneous capillary malformation, bone and soft‐tissue hypertrophy, as well as venous and lymphatic malformations, has been considered by dermatologists as a distinct diagnostic entity. However, cases with KTS have also been reported to have neurological disorders, developmental delay and digital abnormalities, indicating multisystem involvement. Recently, a number of overgrowth syndromes, with overlapping phenotypic features with KTS, have been identified; these include MCAP and CLOVES syndromes as well as fibroadipose hyperplasia. These conditions harbour mutations in the PIK3CA gene, and they have been included in the PIK3CA‐related overgrowth spectrum (PROS). Based on recent demonstrations of PIK3CA mutations also in KTS, it appears that, rather than being a distinct diagnostic entity, KTS belongs to PROS. These observations have potential diagnostic and therapeutic implications for KTS.