Case report: MEK inhibitor as treatment for multi-lineage mosaic KRAS G12D-associated epidermal nevus syndrome in a pediatric patient.

The RASopathies, collectively, are a spectrum of genetic syndromes caused by mutations in genes involved in the RAS/ mitogen-activated protein kinase (MAPK) pathway, including but not limited to PTPN11, NRAS, KRAS, HRAS, BRAF, and MAP2K1. Recognized RASopathy conditions include neurofibromatosis type 1 (NF1), Noonan syndrome, capillary malformation-arteriovenous malformation syndrome, Costello syndrome, cardiofacio-cutaneous (CFC) syndrome, LEOPARD syndrome and Legius syndrome. The RASopathies often display overlapping clinical features, presumably owing to common RAS-MAPK signaling pathway activation driving dysregulated cell proliferation. Epidermal nevus syndromes (ENS) are described as the presence of epidermal nevi, in individuals also affected by extra-cutaneous organ system involvement, and there is recent recognition of mosaic RAS mutations as molecular drivers of ENS. Currently, no curative treatments exist for RASopathy driven conditions, but rather symptom-directed management is the currently accepted standard. Here, we detail a unique case of a child exhibiting diffuse spinal nerve root hypertrophy in the context of epidermal nevus syndrome driven by molecularly confirmed KRAS G12D mosaicism, treated with the MEK 1/2 inhibitor selumetinib. Herein, we report the response of this patient to targeted therapy of more than two years' duration, including stabilization of multilevel nerve root hypertrophy as well as significant improvement in epidermal nevi. While the effectiveness of MEK inhibitors such as selumetinib is established in NF1-associated inoperable plexiform neurofibromas, their use in managing hyperactive KRAS-driven epidermal nevi and hypertrophic neuropathy remains unproven, and this case, to our knowledge, is the first such case to be reported. Shared molecular dysregulation and overlapping clinical features between these conditions suggest potential for effective therapeutic application of MEK directed therapy to address a range of conditions resulting from germline and/ or mosaic expression of aberrantly regulated RAS signaling.

Ophthalmologic manifestations of organoid nevus syndrome: A series of 13 cases.

Background: The organoid nevus syndrome is a rare neurocutaneous syndrome typified by cutaneous sebaceous nevus, seizures and epibulbar choristomas. The condition is associated with multiple ocular abnormalities. Herein, the authors aim to study and report the ophthalmic features of cases diagnosed with organoid nevus syndrome. Methods: The authors retrospectively evaluated the records of patients with the organoid nevus syndrome who had presented to a tertiary care eye hospital in northern India. The ocular features were studied and entered in MS excel and the data were evaluated. Results: Data of 13 patients with the organoid nevus syndrome were found. All 13 patients had cutaneous features in the form of Sebaceous nevus of Jadasson, 8 patients had alopecia of the scalp area, 2 had history seizures and 10 had arachnoid cysts on neuroimaging of the head. All 13 patients had a complex choristoma involving the ocular surface. Conclusions: We conclude that the most common ophthalmologic features associated with organoid nevus are complex choristoma of the bulbar surface, scleral coat calcification and upper eyelid coloboma.

Follicular Becker's nevi: A case series and review of literature.

The follicular variant of Becker's nevus is an under-reported entity. We present the rare occurrence of follicular Becker's nevus in 7 patients, confirmed through dermoscopy and histopathological examination. Dermoscopy shows perifollicular hypopigmentation surrounded by a well-defined net-like pigmentation corresponding clinically to the presence of folliculocentric macules. Histology shows prominent basal and suprabasal melanization surrounding the follicle, corresponding to well-defined net-like pigmentation seen on dermoscopy. However, the melanization does not extend along the entire length of the follicular epithelium leading to perifollicular hypopigmentation on dermoscopy. Though biopsy is confirmatory, it is not usually necessary.

Inflammatory linear verrucous epidermal nevus in groin and labia with claudication: Successfully treated with photodynamic therapy.

SIGNIFICANCE: Inflammatory linear verrucous epidermal nevus (ILVEN) is an uncommon type of epidermal nevus and is refractory to therapy. We report the effectiveness of photodynamic therapy (PDT) for treating ILVEN with claudication in a young girl. ADDITIONAL CONTRIBUTIONS: We thank the patient for granting permission to publish this information. APPROACH: Aminolaevulinic Acid Hydrochloride (ALA) photodynamic therapy (PDT) was applied six times in 1-month interval. RESULTS: Most lesions and pruritus have subsided markedly, with mild scarring and a marked reduction in claudication. CONCLUSIONS: ALA PDT might be an effective and promising treatment for ILVEN in the future.

Case Report: Sequential postzygotic HRAS mutation and gains of the paternal chromosome 11 carrying the mutated allele in a patient with epidermal nevus and rhabdomyosarcoma: evidence of a multiple-hit mechanism involving HRAS in oncogenic transformation.

We report a 7-year-old boy born with epidermal nevi (EN) arranged according to Blaschko's lines involving the face and head, right upper limb, chest, and left lower limb, who developed a left paratesticular embryonal rhabdomyosarcoma at 18 months of age. Parallel sequencing identified a gain-of-function variant (c.37G>C, p.Gly13Arg) of HRAS in both epidermal nevus and tumor but not in leukocytes or buccal mucosal epithelial cells, indicating its postzygotic origin. The variant accounted for 33% and 92% of the total reads in the nevus and tumor DNA specimens, respectively, supporting additional somatic hits in the latter. DNA methylation (DNAm) profiling of the tumor documented a signature consistent with embryonal rhabdomyosarcoma and CNV array analysis inferred from the DNAm arrays and subsequent MLPA analysis demonstrated copy number gains of the entire paternal chromosome 11 carrying the mutated HRAS allele, likely as the result of paternal unidisomy followed by subsequent gain(s) of the paternal chromosome in the tumor. Other structural rearrangements were observed in the tumours, while no additional pathogenic variants affecting genes with role in the RAS-MAPK and PI3K-AKT-MTOR pathways were identified. Our findings provide further evidence of the contribution of "gene dosage" to the multistep process driving cell transformation associated with hyperactive HRAS function.

Noninvasive imaging exploration of phacomatosis pigmentokeratotica using high-frequency ultrasound and optical coherence tomography: Can biopsy of PPK patients be avoided?

BACKGROUND: Phacomatosis pigmentokeratotica (PPK) is a distinct and rare type of epidermal nevus syndrome characterized by coexisting nonepidermolytic organoid sebaceous nevus (SN) with one or more speckled lentiginous nevi (SLN). Atypical nevi including compound Spitz and compound dysplastic may manifest within regions of SLN. Patients with PPK, or similar atypical nevus syndromes, may be subject to a significant lifetime number of biopsies, leading to pain, scarring, anxiety, financial burden, and decreased quality of life. The current literature includes case reports, genetics, and associated extracutaneous symptoms of PPK, but use of noninvasive imaging techniques have not been explored. We aim to investigate the value of high-frequency ultrasound (HFUS) and optical coherence tomography (OCT) in discriminating morphological features of pigmented lesions and nevus sebaceous within one patient with PPK. MATERIALS AND METHODS: Two modalities, (1) HFUS imaging, based on acoustic properties and (2) OCT imaging, based on optical properties, were used to image a patient with PPK. Benign pigmented lesions, which may raise clinical suspicion for significant atypia, and nevus sebaceous, were selected on different areas of the body to be studied. RESULTS: Five pigmented lesions and one area of nevus sebaceous were imaged and analyzed for noninvasive features. Distinct patterns of hypoechoic features were seen on HFUS and OCT. CONCLUSION: HFUS provides a deep view of the tissue, with ability to differentiate gross structures beneath the skin. OCT provides a smaller penetration depth and a higher resolution. We have described noninvasive features of atypical nevi and nevus sebaceous on HFUS and OCT, which indicate benign etiology.

HRAS-related epidermal nevus syndromes: Expansion of the spectrum with first branchial arch defects.

Epidermal nevus syndrome (ENS) comprises a heterogeneous group of neurocutaneous syndromes associated with the presence of epidermal nevi and variable extracutaneous manifestations. Postzygotic activating HRAS pathogenic variants were previously identified in nevus sebaceous (NS), keratinocytic epidermal nevus (KEN), and different ENS, including Schimmelpenning-Feuerstein-Mims and cutaneous-skeletal-hypophosphatasia syndrome (CSHS). Skeletal involvement in HRAS-related ENS ranges from localized bone dysplasia in association with KEN to fractures and limb deformities in CSHS. We describe the first association of HRAS-related ENS and auricular atresia, thereby expanding the disease spectrum with first branchial arch defects if affected by the mosaic variant. In addition, this report illustrates the first concurrent presence of verrucous EN, NS, and nevus comedonicus (NC), indicating the possibility of mosaic HRAS variation as an underlying cause of NC. Overall, this report extends the pleiotropy of conditions associated with mosaic pathogenic variants in HRAS affecting ectodermal and mesodermal progenitor cells.

Combination of Non-Ablative Fractional Laser with Q-Switched Laser for the Treatment of Becker's Nevus: Efficacy and Limitations.

Becker's nevus (BN) is a benign hamartoma that may present as a distressing cosmetic problem. The treatment of BN poses a significant challenge as current therapeutic modalities are suboptimal and have an increased risk of adverse effects, such as scarring and dyspigmentation. We present the use of non-ablative fractional laser therapy combined with Q-switched Nd:YAG laser as a possible therapeutic option for BN treatment and review relevant literature to discuss its efficacy and limitations.

Epidermal nevus superimposed by psoriatic plaque in a girl with proteous syndrome.

Proteus syndrome (PS) is a rare syndrome characterized by asymmetric limb overgrowth, vascular malformation, and hamartomas. In this study we report a case of PS in a 13-year-old girl with chief complaint of a new cutaneous lesion that was diagnosed and treated as leishmaniasis.

Verrucous epidermal nevus as a manifestation of a type 2 mosaic PTEN mutation in Cowden syndrome.

Linear Cowden nevus, also known as linear PTEN nevus, is a type of epidermal nevus, first described in 2007, which is seen in patients with PTEN hamartoma tumor syndrome. It is considered to be a type 2 form of segmental mosaicism, and we suggest that it has certain clinical features that distinguish it from epidermal nevi seen in similar conditions, such as Proteus syndrome. We present a case of linear Cowden nevus in a 4-year-old boy and review the literature.

Searching beyond nevi - A rare case of neurocutaneous ocular syndrome.

Epidermal nevus syndrome is a rare congenital disorder affecting only a few hundred people in the world. It has ophthalmic, dermatological, and neurological manifestations, with varied presentation. Here, we report a case of two-year-old child who presented with epibulbar mass in left eye, pigmented nevi over left side of the body and alopecia over left side of parieto-temporal scalp. Imaging confirmed epibulbar mass and presence of calcification of choroid on ipsilateral side with presence of arachnoid cyst of brain with underlying pachygyria. Neurological examination was normal and dermatologist confirmed presence of verrucous nevi over skin. Excisional biopsy of epibulbar mass revealed a complex choristoma with presence of lacrimal gland tissue. Underlying ocular findings were near normal with normal posterior segment. It is a rare form of epidermal nevus syndrome with near normal ocular findings in the presence of anterior and posterior choristoma, which has not been reported.

The efficacy and safety of burosumab in two patients with cutaneous skeletal hypophosphatemia syndrome.

Cutaneous skeletal hypophosphatemia syndrome (CSHS) is an ultra-rare mosaic disorder manifesting as skeletal dysplasia and FGF23-mediated hypophosphatemia, with some experiencing extra-osseous/extra-cutaneous manifestations, including both benign and malignant neoplasms. Like other disorders of FGF23-mediated hypophosphatemia including X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO), patients with CSHS have low serum phosphorus and active 1,25-dihydroxyvitamin D levels. Current treatment options for patients with CSHS include multiple daily doses of oral phosphorus and one or more daily doses of active vitamin D analog to correct the deficits. Recently, the fully human monoclonal antibody against FGF23 burosumab received US approval for the treatment of XLH and TIO, two rare diseases characterized by FGF23-mediated hypophosphatemia leading to rickets and osteomalacia. Given the similarities between the pathobiologies of these disorders and CSHS, we investigated the impact of burosumab on two patients, one pediatric and one adult, with CSHS who participated in separate, but similarly designed trials. In both the pediatric and adult patients, burosumab therapy was well-tolerated and contributed to clinically meaningful improvements in disease outcomes including normalization of phosphorus metabolism and markers of bone health, and improvements in skeletal abnormalities, fractures, and physical function. Reported adverse events were minimal, with only mild injection site reactions attributed to burosumab therapy. Together, these findings suggest that burosumab therapy is a promising therapeutic option for patients with CSHS.

A Case Report of Nevus Trichilemmocysticus / 罕见病研究

This article reports a case of nevus trichilemmocysticus. The patient, a 48-year-old man, presented with multiple filiform keratoses and nodules. Physical examination identified multiple subcutaneous papules and nodules on the scalp, filiform keratoses on the face and bilateral ears, in addition to linear blackheads on trunk and limbs. The patient also exhibited hair loss and hypoplastic tooth. Histopathology revealed trichilemmal cyst. Nevus trichilemmocysticus is a rare organoid nevus. We reviewed literature in order to raise the awareness of the syndrome.