Secondary neoplasms associated with nevus sebaceus of Jadassohn: a study of 707 cases

Combined Melanocytic Nevus and Nevus Sebaceus: A Case Series and Review of the Literature

ABSTRACT

Nevus sebaceus is a rare congenital hamartoma with clinical and histopathological features that change with puberty. It has been associated with a number of secondary neoplasms, most of which are thought to derive from follicular germ cells. In this article, the authors describe a total of 3 cases of combined melanocytic nevus and nevus sebaceus to highlight this rare finding.

Facial Soft Tissue Lesions in Children

Facial soft tissue lesions in children are often classified based on their structure or cellular origin and can be benign or malignant. This review focuses on common facial soft tissue lesions in children, their clinical morphology, natural history, and medical and surgical management, with an emphasis on those considerations unique to soft tissue lesions present at this anatomic site.

Rate of Benign and Malignant Secondary Tumors Associated With Nevus Sebaceous: A Systematic Review and Meta-Analysis

BACKGROUND

Nevus sebaceous (NS) is a rare congenital skin lesion affecting approximately 0.3% of all newborns. Although benign, NS lesions can harbor malignant secondary tumors. The published rate of development of these malignant tumors varies. This meta-analysis aimed to identify the rate of malignant and benign secondary neoplasms occurring in NS.

METHODS

A literature search was conducted using PubMed, Embase, and Web of Science from inception to April 2023. Eligible studies reported incidence or risk of secondary neoplasms in patients with NS. Two independent reviewers screened studies, extracted data, and assessed the quality of included studies. The primary outcome was the pooled incidence of secondary neoplasms. Studies with sample sizes greater than 50 patients were eligible for meta-analysis using the random-effects model.

RESULTS

Twenty-eight studies were identified, 22 of which were eligible for meta-analysis. The overall rate of secondary neoplasms was 12.8% (95% confidence interval [Cl], 9.2%-17.6%). The rates of development of malignant and benign tumors were 2.4% (95% CI, 1.4%-4.1%) and 10.3% (95% CI, 7.5%-13.9%), respectively. The rate of development of basal cell carcinoma was 1.7% (95% CI, 0.9%-3.2%), whereas the rate of the development of syringocystadenoma papilliferum was 3.6% (95% CI, 2.5%-5.3%) and that if trichoblastoma was 2.6% (95% CI, 1.7%-3.8%).

CONCLUSIONS

Although the rate of development of malignant tumors within a primary NS lesion is low, it is not negligible. Prophylactic early excision remains a viable approach to prevent secondary malignant neoplasms, address cosmetic and functional complications, and preempt the need for complex reconstruction in the future. We propose that resection of NS lesions in childhood remains a reasonable first-line option in the appropriate patient keeping in mind that it may leave an undesirable scar.

Managing a Misdiagnosed Case of Nevus Sebaceous

A male patient in his early 20s presented to our outpatient clinic, having previously been misdiagnosed and unsuccessfully treated as a case of viral warts. Dermoscopic and histopathological evaluations revealed characteristic features of the nevus sebaceous. The lesion was eventually treated with an erbium-doped yttrium aluminum garnet (Er:YAG) laser after the patient declined surgical excision. Nevus sebaceous often presents with verrucous surfaces that make misdiagnosis common. A correct diagnosis is crucial due to potential neoplastic transformations. Histopathological analysis is essential for both the confirmation of disease and the exclusion of malignancy. Full-thickness surgical excision remains the preferred treatment.

Papular lesion occurring within a longstanding warty plaque, in skin of colour Fitzpatrick type 4-5

A 23-year-old man of South Asian descent, Fitzpatrick type 4-5 skin, usually fit and well, presented with a 6-month history of a darkly-pigmented papular lesion growing within a pre-existing warty plaque on the left parietal scalp, present since birth. The base plaque measured 30 × 10 mm, whilst the new papule measured approximately 3 × 3 mm. These were asymptomatic and there was no preceding trauma to the area. Examination revealed a pearlescent darkly pigmented papule, growing within a warty pink-yellow hairless plaque. Dermoscopy showed non-specific features with evidence of some disorganized vasculature. A punch excisional biopsy of the papular lesion was obtained, histopathology indicated a polypoid lesion with basaloid nests in a superficial and nodular distribution extending to the superficial dermis. The base plaque was then completely excised, showing dermal scarring related to the previous excision, along with the presence of large sebaceous glands, heterotopic apocrine glands, defective hair follicles, acanthosis and epithelial papillomatosis. This is a case of a basal cell carcinoma (BCC) arising within a sebaceous naevus on the scalp, in a skin of colour patient. Sebaceous naevi (SN), also known as naevus sebaceous of Jadassohn, are benign hamartomatous malformations comprised of predominantly sebaceous glands. SN appear most commonly on the scalp, and start off as smooth yellowish well-circumscribed plaques in infancy which then develops a verrucous appearance in adolescence due to hormonally-driven maturation of sebaceous and apocrine glands. It is well known that benign neoplasms of various lineages of differentiation including follicular, sebaceous, apocrine or eccrine, may arise within SN. Malignant neoplasms occurring within SN almost exclusively occur in adults, and arise in about 2.5% of lesions. BCCs are the most common among these, and occur in 0.8% of SN. Other malignant tumours such as squamous cell carcinoma, sebaceous carcinoma, microcystic adnexal carcinoma and porocarcinoma can also arise within SN, but these are rarer. Our case is notable as our patient had Fitzpatrick skin type 4-5, hence may have been perceived to have a lower risk of developing BCCs. We hope that this report will highlight that BCCs do arise even in skin of colour.

Basal cell carcinoma arising within nevus sebaceous on the right scalp in a 55-year-old male: A case report and review of literature

We report here a case of nevus sebaceous in a 55-year-old male, who presented with a 50-year history of an asymptomatic swelling in his right scalp. The solitary, yellowish, expansile plaque over the scalp gradually became lobulated and turned dark-pigmented with spontaneous bleeding, itching discomfort, and occasional ulceration after scratching. The male's clinical presentation and histopathological findings were compatible with basal cell carcinoma arising in nevus sebaceous. At present, 5-aminolevulinic acid photodynamic therapy (ALA-PDT) emerges as a novel treatment modality which has proved safe and effective. In this case, three sessions of photodynamic therapy in combination with surgical excision were performed, leaving mild pigmentation within 3 weeks. The patient showed good cosmetic outcome, minimal scarring on the right scalp without further complications, disease recurrence or metastasis after ALA-PDT within six months.

Next generation sequencing aids diagnosis and management in a case of encephalocraniocutaneous lipomatosis

Encephalocraniocutaneous lipomatosis (ECCL) is a rare neurocutaneous disorder caused by somatic FGFR1 and KRAS variants. It shares significant phenotypic overlap with several closely related disorders caused by mutations in the RAS-MAPK pathway (mosaic RASopathies). We report a diagnostically challenging case of ECCL in which next-generation sequencing of affected tissue identified a pathologic FGFR1 p.K656E variant, thereby establishing a molecular diagnosis. Patients with FGFR1-associated ECCL carry a risk of developing malignant brain tumors; thus, genetic testing of patients with suspected ECCL has important management implications.

Whole-exome sequencing of secondary tumors arising from nevus sebaceous revealed additional genomic alterations besides RAS mutations

Nevus sebaceous (NS) is a congenital hamartoma associated with an increased risk of secondary neoplasms in approximately 10%-20% of patients. However, additional genomic alterations underlying tumorigenesis in NS lesions have not been clarified. We performed whole-exome sequencing of archived tumor tissues (n = 8; six basal cell carcinomas and two trichoepitheliomas) and matched germline tissues (n = 7) with from seven patients with secondary tumors arising from NS. We also analyzed NS lesions without secondary tumors (n = 8). Somatic mutations and copy number alterations (CNAs) were analyzed. We identified a median of 129 somatic mutations (corresponding to 2.6/Mb in target regions, range 26-336) for eight tumors, while a median of 118 somatic mutations (2.3/Mb, range 1-196) for eight NS lesions. Known RAS hotspot mutations were found in seven of the eight tumors (six for HRAS p.G13R and one for HRAS p.Q61R) and in six of the eight NS lesions (four for HRAS p.G13R, one for KRAS p.G12C, and one KRAS p.G12D). Except RAS mutations, several putative driver mutations were detected in tumors: TP53 p.F134L/p.R213*, MYCN p.P59L, OR2Z1 p.P167S, PTPN14 p.Q768*, and SMO p.W535L. As for CNAs, two tumors harbored copy-loss in regions encompassing PTCH1 gene. However, eight NS lesions did not harbor both putative driver mutations and CNAs. In conclusion, our study revealed that secondary tumors arising from NS harbor known RAS hotspot mutations and additional genomic alterations, including putative driver mutations and PTCH1 copy-loss. These results could help to define the high-risk group for tumor development in patients with NS and provide evidence for prophylactic resection.

SCALP syndrome with a germline heterozygous DOCK6 mutation and somatic mosaic NRAS Q61R mutation

We present a case of SCALP syndrome, which was diagnosed in a male infant with the characteristic findings of sebaceous nevi, central nervous system malformations, aplasia cutis congenita, limbal dermoid, and giant congenital melanocytic nevi, or pigmented nevi. We identified a germline compound heterozygous DOCK6 mutation and a somatic mosaic NRAS Q61R mutation in the giant congenital melanocytic nevus. This report will increase clinician awareness of SCALP syndrome and augment the literature in characterizing this rare syndrome, including its genetic background.

Primary Cutaneous Apocrine Carcinoma and Syringocystadenoma Papilliferum Arising in Nevus Sebaceus: A Case Report and Review of the Literature

Nevus sebaceus is a hamartomatous lesion characterized by epidermal, follicular, sebaceus, and apocrine gland abnormalities. Approximately 25% of affected individuals may develop benign or malignant secondary neoplasms within the preceding nevus sebaceus. Primary cutaneous apocrine carcinoma (PCAC) is a rare malignant skin tumor affecting elderly adults in their sixth decade of life. Histologically, PCAC appears as a dermal tumor displaying apocrine differentiation with decapitation secretion and malignant features. Secondary malignancy arising from nevus sebaceus is a rare complication, especially for apocrine carcinoma. To date, approximately 200 cases of PCAC have been reported in the literature, and only a few cases have developed PCAC on the scalp. Very few cases (approximately only 12) of PCACs developing in nevus sebaceus have been reported. Here, we report an extremely rare case of the coexistence of PCAC and syringocystadenoma papilliferum arising within nevus sebaceus of the scalp.

Nevus Sebaceous of Jadassohn in Adults-Can Reflectance Confocal Microscopy Detect Malignant Transformation?

Nevus sebaceous of Jadassohn (NSJ) is a rare congenital lesion that affects the adnexal structures of the skin. It is typically located on the scalp and face of females and presents as a well-defined, slightly elevated, yellow lesion. It is also linked to a high risk of secondary tumors, which are more frequently benign than malignant. In vivo reflectance confocal microscopy (RCM) is a non-invasive imaging technique that provides a horizontal image of the skin with a resolution similar to histology. We report a case of basal cell carcinoma (BCC) developed in an NSJ with its dermoscopic, confocal, and histopathological features. A 49-year-old female presented with a well-circumscribed, 1 cm-diameter verrucous, yellowish lesion surrounded by a poorly defined, slightly erythematous, translucent plaque, located on the scalp in the temporoparietal region, which had been present since birth, grew at puberty, and changed its appearance in the last three years. Dermoscopy of the central lesion revealed yellow globules grouped into clusters, with peripheral linear and arborescent thin vessels, surrounded by several translucent nodular lesions with fine, arborizing vessels. RCM examination showed large, monomorphic cells with a hyperreflective periphery and a hyperreflective center located on the central lesion, corresponding to sebocytes, surrounded by multiple dark silhouettes lined with hyperreflective bands of thickened collagen, corresponding to tumor islands. The histopathological findings confirmed the diagnosis of BCC developed on an NJS. RCM can be a useful technique for the non-invasive examination and monitoring of these lesions, taking into account their transformation risk and preventing unnecessary excisions that might have a detrimental aesthetic impact on patients.

Metastasis of a basosquamous carcinoma arising in a nevus sebaceus

Nevus sebaceus (NS) is a congenital hamartoma of skin structures including the epidermis, sweat sebaceous glands, and hair follicles. It is known that secondary tumors can occur in NS. However, secondary metastatic malignancies are rare. Basosquamous carcinoma (BSC) is an aggressive type of basal cell carcinoma (BCC) characterized by squamous differentiation. Herein, we report a case of metastatic BSC that developed in a 73-year-old male with NS. The clinical presentation of this patient was that of an ulcerative nodule developing in a longstanding plaque-like lesion consistent with NS. Histopathological examination revealed characteristic features of BCC with some areas of squamous differentiation in addition to the structure of a typical NS. Immunohistochemical expression of Ber-EP4, AE1/AE3, and epithelial membrane antigen helped to make the diagnosis of BSC.

Infant with Parotid Sialoblastoma and Nevus Sebaceous, Treated with Surgery and Adjuvant Chemotherapy

Sialoblastoma is an extremely rare embryonal tumor derived from salivary gland primordial cells. Treatment usually consists of surgery alone; however, in some cases, chemotherapy is required and is administered with good response. We present a case of a 5-week-old girl diagnosed with a parotid gland tumor and co-existing nevus sebaceous on the face. Initial tumorectomy was microscopically non-radical and histopathology revealed sialoblastoma. The patient received adjuvant chemotherapy consisting of vincristine, actinomycin, and cyclophosphamide. Due to imaging studies being inconclusive regarding response and possible residual disease, a second surgery (total parotidectomy) was performed. The histopathology results showed fields of necrosis in the parotid gland but no neoplastic cells in the material. The patient remains under watchful observation and there is no evidence of relapse 12 months after the second surgery. The adjuvant chemotherapy regimen with vincristine, actinomycin, and cyclophosphamide is a viable option of treatment in children with sialoblastoma.

Malignant Melanoma Arising in a Prolific Nevus Sebaceus With Colonization of Trichoblastoma

ABSTRACT

Nevus sebaceus (NS) is a cutaneous hamartoma typically found on the head and neck, with a prevalence of 0.3% in newborns. Most NS are quiescent; however, benign and malignant lesions have been reported to arise within these nevi. Malignant transformation is not common but mainly includes basal cell carcinoma and squamous cell carcinoma. Malignant melanoma arising in NS is exceedingly rare, with only 2 previously documented cases. In this article, we report the first case of malignant melanoma arising in a NS in a 68-year-old man in the United States.

Atypical Nevus Sebaceus at an Unusual Location Treated with Carbon Dioxide Laser: A Case Report

Nevus sebaceus (NS) or organoid nevus is an epidermal nevus comprising predominantly sebaceous glands with a prevalence of approximately 0.3% of the newborns. The initial clinical manifestations of NS are single or less commonly multiple yellowish patches with overlying alopecia, usually confined to the scalp. However, it can also appear on the face, preauricular area, and the neck. During puberty, skin lesions will turn into round or linear verrucous plaques accompanied with an increase in number due to the influence of androgens. As they progress, about 20% of the NS cases might turn into secondary tumors which can be benign or malignant (in 2.5% cases). NS can manifest as atypical lesions and may also arise on areas other than its predilection sites. A case of a lesion presented on an atypical location of an 18-year-old male patient treated with carbon dioxide (CO₂) laser was reported. Physical examination revealed skin-colored and blackish-brown papules arranged in groups on the left side of the patient's chest. Histopathological examination on a sample taken from one of the skin lesions on the chest showed hyperkeratosis, acanthosis, papillomatosis, and sebaceous hyperplasia, confirming the diagnosis of NS. The patient was treated with CO₂ laser, and clinical improvements were observed. Histopathological examination of NS is not routinely performed; however, it should be carried out when the lesion is atypical and presented at an unusual location, or there is a suspicion of malignancy.

Syringocystadenoma Papilliferum and Basal Cell Carcinoma Arising in Nevus Sebaceous

Nevus sebaceous (NS) is a benign congenital hamartoma with the potential to develop into a secondary benign or malignant skin tumors. Two or more skin tumors rarely arise simultaneously from a single NS lesion. Herein, we report a case of syringocystadenoma papilliferum and basal cell carcinoma arising in an NS, based on dermoscopic, reflectance confocal microscopic, and histopathological findings.

Neurofibroma Within a Nevus Sebaceus: A Case Report

Nevus sebaceus most commonly presents as a yellow, alopecic plaque on the head or neck in childhood and evolves into a verrucous plaque at puberty. Numerous secondary tumors may arise within nevus sebaceus lesions. Tumors of mesenchymal origin have been rarely documented. We present a unique case of a patient who presented with a nevus sebaceus on the scalp. Excision of the tumor and subsequent histopathology of the lesion revealed a nevus sebaceus with a desmoplastic trichilemmoma, a tumor of follicular infundibulum, and a neurofibroma. This case highlights a rare finding of a mesenchymal tumor, and the first reported neurofibroma, arising in association with a nevus sebaceus.

Malignant transformation of nevus sebaceous to basal-cell carcinoma: Case series, literature review, and management algorithm

Nevus sebaceous (NS) is a common congenital hamartoma of the skin composed predominantly of sebaceous glands. Although most NS are benign skin tumors, malignant transformations have been reported. There is still controversy about the lifetime risk of malignant degeneration and precise surgical criteria. This study reports cases of malignant degeneration and suggests a surgical treatment algorithm. The medical records of patients with basal-cell carcinoma (BCC) arising from NS between January 2001 and January 2021 were retrospectively reviewed. Patient demographics including lesion location, and tumor size were investigated. The symptoms, histological findings before and after excision, complications, and recurrence during 2-year follow-up periods were investigated. Ten patients were identified with BCC arising from NS lesions. All patients were female and the mean age was 52.11 years. All patients complained of sudden morphological changes, the most common type being rapid color changes. Two cases had histological findings that showed a miss-match between punch biopsy and excisional biopsy results. No recurrence was detected 2 years after surgeries in any patients. Cases after third stage, especially in over 40 years who report morphologic changes, should undergo total surgical excision as the first approach, with strong suspicion of malignant degeneration.

Trichilemmoma Arising in a Sebaceous Nevus Successfully Treated with Cryotherapy

Nevus sebaceous of Jadassohn (NSJ) is a benign congenital hamartoma composed of follicular, adnexal appendages and epidermal hyperplasia. Various secondary neoplasms, mostly adnexal in origin, can arise within nevus sebaceous. We report the case of a 16-year-old female who had NSJ associated with trichilemmoma, which was successfully treated with cryotherapy. We found cryotherapy to be an effective, satisfactory therapy, with acceptable cosmetic results, especially for patients who have visible lesions that can be easily followed.

Genodermatoses associated with melanocytic nevi

Though melanocytic nevi are ubiquitous in the general population, they can also be key cutaneous manifestations of genetic syndromes. We describe genodermatoses associated with melanocytic nevi and discuss their clinical characteristics, cutaneous manifestations, underlying genetics, and, if applicable, guidelines for when genetic testing should be performed. We categorized these genodermatoses based on their association with congenital nevi, acquired nevi, or nevi whose first appearance is unknown. In many cases, the distinctive morphology or distribution of melanocytic nevi can be an important clue that an underlying genetic syndrome is present, allowing both the patient as well as family members to be screened for the more serious complications of their genetic disorder and receive education on potential preventative measures. As we continue to advance our understanding of how various genotypes give rise to the wide spectrum of phenotypes observed in these genodermatoses, we shall be able to better stratify risk and tailor our screening methods to clinically manage the heterogeneous manifestations of genodermatoses among these patients.

A case of naevus sebaceus of Jadassohn of the scalp in Jamaica

Naevus sebaceus (NS), also referred to as NS of Jadassohn, is a rare non-melanocytic congenital cutaneous hamartoma with mainly sebaceous differentiation. NS has pluripotent potential with the possible evolution of benign and/or malignant neoplastic transformation. Literature of clinical audit and retrospective analyses conclude that there is no need for prophylactic excision except for cases in which malignant transformation is suspected. Although malignant transformation is rare, there are psychosocial issues with which to contend. We present a case of a 5 year-old girl with a cerebriform mass to her right parietal scalp, which was present at birth.

Epidermal Nevi: What Is New

This article reviews the clinical findings of epidermal nevi and their associated syndromes and provides an update on their pathogenic genetic changes as well as targeted therapies detailed to date.

Basal Cell Carcinoma and Sebaceoma Within Nevus Sebaceous of the Scalp

This case describes the occurrence of basal cell carcinoma (BCC) and sebaceoma within a nevus sebaceous (NV), which has not yet been previously reported. This is significant to dermatologists as it emphasizes the importance of close monitoring of benign sebaceous nevi in the event that malignant transformation occurs, although such occurrences are rare. Prompt consideration for prophylactic excision of NS is warranted prior to malignant transformation. 

Case report of a solitary fibrofolliculoma on the alar rim

Fibrofolliculoma is a benign tumor characterized by a smooth, dome-shaped papule of size 2–4 mm. Most fibrofolliculomas occur as multiple lesions, and very rarely, they are solitary. Herein, we report a case of solitary fibrofolliculoma found in the alar rim, without the typical characteristics of a fibrofolliculoma. A 42-year-old man visited the hospital with a protruding lesion that had occurred 1 year previously. A mass of size 5× 7 mm was observed on the left alar rim. The tumor was dome-shaped and palpable. The patient did not have any similar lesions elsewhere. No family member was known to have such a lesion. An incisional biopsy was performed before surgery, and pathological examination revealed hyperkeratosis and dyskeratosis; however, an accurate diagnosis was not made. Complete resection was planned for the mass on the alar rim. The resected mass was subjected to permanent biopsy, and the pathological examination results led to the diagnosis of fibrofolliculoma. Therefore, when diagnosing a dome-shaped mass in the alar rim, despite the suspicion of a very rare disease, it is necessary to suspect fibrofolliculoma and consider the process from diagnostic examination to treatment.

A Rare Occurrence of Sebaceous Carcinoma, Sebaceoma, Syringocystadenoma Papilliferum, and Trichoblastoma in a Single Nevus Sebaceous Lesion

Nevus sebaceous (NS) is a benign tumor with the potential to develop secondary benign and malignant neoplasms. It is a rare phenomenon to develop 2 or more skin tumors in a single NS lesion. We report a case of multiple secondary tumors, such as sebaceoma, sebaceous carcinoma, syringocystadenoma papilliferum, and trichoblastoma, in a single NS lesion.

Update on Molecular Genetic Alterations of Cutaneous Adnexal Neoplasms

Cutaneous adnexal tumors recapitulate follicular, sweat gland, and/or sebaceous epithelia, and range from benign tumors to aggressive carcinomas. Adnexal tumors can be hallmarks for inherited tumor syndromes. Oncogenic drivers of adnexal neoplasms modulate intracellular pathways including mitogen-activated protein kinase, phosphoinositide-3-kinase, Wnt/β-catenin, Hedgehog, nuclear factor κB, and Hippo intracellular signaling pathways, representing potential therapeutic targets. Malignant progression can be associated with tumor suppressor loss, especially TP53. Molecular alterations drive expression of specific diagnostic markers, such as CDX2 and LEF1 in pilomatricomas/pilomatrical carcinomas, and NUT in poromas/porocarcinomas. In these ways, improved understanding of molecular alterations promises to advance diagnostic, prognostic, and therapeutic possibilities for adnexal tumors.

Cerebriform sebaceous nevus: a subtype of organoid nevus due to specific postzygotic FGFR2 mutations

BACKGROUND

Postzygotic mutations in FGFR2 have been identified in mosaic forms of acne, keratinocytic epidermal nevi, nevoid acanthosis nigricans / rounded and velvety epidermal nevus and in two fetuses with papillomatous pedunculated sebaceous nevus (PPSN).

OBJECTIVES

To determine the clinical and genetic characteristics of children with cerebriform, papillomatous and pedunculated variants of sebaceous nevi.

METHODS

Infants diagnosed with sebaceous nevi characterized by a cerebriform, papillomatous and/or pedunculated morphology over a 10-year period (2010-2019) at three paediatric dermatology centres in Switzerland and France were included in this case series. Clinical and histological characteristics were assessed. Next-generation sequencing was used to assess for FGFR2 mutations.

RESULTS

All nevi were located on the head, with a rounded or linear shape and a typical cerebriform, sometimes papillomatous and pedunculated, surface. No associated extracutaneous anomalies were found. Nevi harboured postzygotic mutations in the transmembrane domain of FGFR2 in 6/8 children (75%), either the known specific p.(Cys382Arg) mutation in 5 cases, or a novel mutation, p.(Val395Asp), in one.

CONCLUSIONS

We found an exquisite genotype-phenotype correlation in these rare nevi, with specific postzygotic mutations in the transmembrane domain of FGFR2. As not all lesions were truly papillomatous and pedunculated, the term cerebriform sebaceous nevus (CSN) appears more suitable than PPSN to describe this entity. The cerebriform pattern of CSN is reminiscent of cutis gyrata, as seen in Beare-Stevenson syndrome, which is caused by closely related germline FGFR2 mutations. While clinically impressive, CSN seem to carry a good prognosis and a low risk for extracutaneous associations.

Genetic analyses of a secondary poroma and trichoblastoma in a HRAS-mutated sebaceous nevus

A sebaceous nevus is a congenital skin hamartoma caused by postzygotic HRAS or KRAS mosaic mutations. With age, affected individuals may develop secondary tumors within a sebaceous nevus. RAS mutations are harbored from the onset of sebaceous nevus, and further mutations can be expected to be required in order to explain the initiation of secondary tumors. However, genetic analyses of the secondary tumors have not been conducted. Herein, we describe the rare coexistence of a poroma and a trichoblastoma arising in a sebaceous nevus. This is the first report of an investigation of multiple genes in a secondary tumor in an SN. First, HRAS c.37G>C, which is the common mutation in sebaceous nevus, was detected in all three lesions (sebaceous nevus, poroma, and trichoblastoma). Next, to elucidate the potential second-hit mutations in the secondary poroma and trichoblastoma, we applied a panel sequencing for skin cancers that was newly developed in our institution. Our comparison of the mutational profile of 95 skin cancer-related genes in each of the three lesions newly revealed TP53 p.R158P in the poroma and NOTCH2 p.G329S in the trichoblastoma. TP53 p.R158P has been determined as a pathogenic mutation in other tumors, and NOTCH2 p.G329S was a novel mutation. We identified two novel mutations that may have contributed to the pathogenesis of the secondary tumor's development. The roles of the mutations remain unclear.

Secondary Tumor Arising in a Nevus Sebaceous

Introduction. Nevus sebaceous is a rare congenital hamartoma, composed of epidermis, sebaceous glands, sweat glands and hair follicles. It is possible to develop secondary tumors in the area of nevus sebaceous during the lifetime, most often after puberty. Secondary lesions are most often benign, while malignant lesions may occur but significantly less frequently.

Case report. We present the case of a 21-year-old patient who came for an examination due to the appearance of a nodule in the area of a yellowish lesion on the head. The yellowish lesion was present since birth, and the nodule appeared about a year before. The dermoscopic examination of the lesion was nonspecific. The final diagnosis of eccrine poroma as a secondary lesion in nevus sebaceous was made by pathohisto-logical analysis.

Conclusion. Every secondary tumor in nevus sebaceous deserves full attention, with either close follow up, or excision with pathohistological analysis.

Review of Pediatric Head and Neck Neoplasms that Raise the Possibility of a Cancer Predisposition Syndrome

Cancer predisposition syndromes (CPS) are generally heritable conditions that predispose individuals to develop cancer at a higher rate and younger age than their representative general population. They are a significant cause of cancer related morbidity and mortality in the pediatric population. Therefore, recognition of lesions that may be associated with a CPS and alerting the clinicians to its implications is a crucial task for a diagnostic pathologist. In this review we discuss benign pediatric head and neck lesions associated with CPS namely: odontogenic keratocyst, juvenile nasopharyngeal angiofibroma, ossifying fibroma of the jaw, paraganglioma, plexiform neurofibroma, plexiform schwannoma, mucosal neuroma, and nevus sebaceous syndrome; along with malignant tumors such as squamous cell carcinoma. Several head and neck melanocytic, endocrine, and central nervous system tumors can also be associated with CPS; they are beyond the scope of this article. Nasal chondromesenchymal hamartoma is discussed elsewhere in this issue.

A rare case of nevus sebaceous of the bilateral labia minora: A case report and review of literature

RATIONALE

Nevus sebaceous (NS) is a lesion caused by congenital hyperplastic disorder of the sebaceous glands. It commonly noted in the scalp and face and rarely in the trunk, neck, or oral mucosa. We present a rare case of a lesion arising in the genital region.

PATIENT CONCERNS

A 47-year-old woman complained of a gradual increase in the size of her bilateral labia minora over 2 years, which affected her sexual life and caused walking difficulty. She was admitted to the Department of Obstetrics and Gynecology. On physical examination, no ulcer, discharge, and vulval or vaginal bleeding were found. The bilateral inguinal lymph nodes were not palpable, bilateral labia minora were asymmetric, and the right side was evidently bigger than the left. The labia minora had serrated edges and numerous papillae with a maximum diameter of 0.5 cm. The vagina, cervix, and uterus with its attachments were normal. Blood samples tested negative for human immunodeficiency virus, human papilloma virus, hepatitis B virus, and hepatitis C virus.

DIAGNOSIS

A diagnosis of NS of the bilateral labia minora was made following histopathological examination of the resected specimen.

INTERVENTION

The bilateral labia minora lesions were resected general anesthesia on August 29, 2016. The operation was successful, and intraoperative blood loss was about 10 ml.

OUTCOMES

After 40 months of postoperative follow-up, no recurrence or appearance of other tumors were noted.

LESSONS

We recommend surgical removal of lesions in the genital area during adolescence or before adulthood. Adolescence may be the best period for surgical intervention owing to a greater risk of malignant change in adulthood. On the other hand, surgical risk should be avoided in children considering the low incidence of malignant transformation.

A Rare Case of Porocarcinoma and Trichoblastoma Arising in a Nevus Sebaceus of Jadassohn

Nevus sebaceus of Jadassohn, or "organoid nevus," is a common, benign hamartoma of the skin consisting of epithelial and adnexal components. Its natural history and association with neoplastic growths is well documented. The majority of concomitant neoplasms are benign-trichoblastoma and syringocystadenoma papilliferum are most frequently discovered-but malignant tumors have been described. We present the case of a 58-year-old male with a congenital nevus sebaceus of Jadassohn on his left parietal scalp that had been enlarging, changing color, and bleeding over the prior year. Clinical exam and histology disclosed the presence of a trichoblastoma and porocarcinoma arising within the nevus sebaceus. Porocarcinoma is a rare, intermediately aggressive, malignant eccrine gland tumor that is frequently metastasized at presentation. Otolaryngology performed wide local resection with sentinel lymph node biopsy. This case highlights the diversity of tumors associated with nevus sebaceus of Jadassohn, potential for malignant expansion, and necessity for close monitoring and maintaining a low threshold for biopsy in evolving lesions.

Nevus sebaceus of Jadassohn - high frequency ultrasound imaging and videodermoscopy examination. Case presentation

Nevus sebaceus of Jadassohn (NSJ) is a congenital cutaneous hamartoma mainly developing from pilosebaceous unit cells. NSJ has the potential to develop into a variety of benign and malignant tumors, which are not limited to sebaceous differentiation. The dynamical monitoring for the earliest malignant transformation is necessary. Herein, we report the combined noninvasive NSJ examination with videodermoscopy in polarized and non-polarized light and high-frequency ultrasound (HFUS) imaging at 33 and 50 MHz. Typical NSJ dermoscopic signs where described, the internal nevus structure and its location, depths, and margins with surrounded tissues were examined with high-frequency ultrasound.

Some HFUS characteristics for NSJ were described. Videodermoscopy and high-frequency ultrasound combined examination could be useful for NSJ dynamical monitoring in order to detect malignant transformation and to define necessary and sufficient tissue excision volume in case of surgical treatment.

Ultrasound Imaging of Nevus Sebaceous of Jadassohn

Nevus sebaceous of Jadassohn (NSJ) is a cutaneous hamartoma commonly found in the scalp and face and more frequent in children. Clinically, it presents as a yellowish and hairless plaque. In later stages, the NSJ can develop secondary tumors, including skin cancer. We reviewed the ultrasound characteristics of 9 patients (67% female; mean age, 3 years) with NSJ at 18 and 70 MHz. The ultrasound analysis covers the data on the location, thickness, echo structure, and vascularity. The provision of the ultrasound patterns of NSJ can support early diagnosis, avoid unnecessary biopsies, and support monitoring.

Squamous Cell Carcinoma within a Congenital Nevus Sebaceous: Case Report and Literature Review

Nevus sebaceous (NS) is a benign hamartoma that typically occurs on the head and neck area at birth. Occasionally, secondary neoplasms can develop on top of the original nevus, which usually occur in the middle age. Squamous cell carcinoma (SCC) arising in NS may occur but is very rare. We report the case of a 44-year-old female with an asymptomatic erythematous papule arising within a hairless yellowish plaque on the left parietal area of her scalp for a month. An excisional biopsy was done, and the histopathologic examination revealed SCC arising in the NS.

Identification of KRAS mutation in a patient with linear nevus sebaceous syndrome: a case report

Background

Linear nevus sebaceous syndrome (LNSS) is a rare genetic disease characterized by large linear sebaceous nevus typically on the face, scalp, or neck. LNSS could be accompanied by multisystem disorders including the central nervous system. Herein, we report gene mutational profile via whole exome sequencing of both lesional and non-lesional skin samples in a LNSS patient.

Case presentation

A 17-year-old girl presented with multisystem abnormalities, including large skin lesions, ocular disorders, abnormal bone development and neurological symptoms. A diagnosis of LNSS was established based on clinical manifestations, histopathological and imaging findings. The skin lesions were resected and no recurrence was noted at the time of drafting this report. Whole exome sequencing of genomic DNA revealed the following 3 mutations in the lesions of the index patient: KRAS (c.35G > A, p.G12D), PRKRIR (c.A1674T, p.R558S), and RRP7A (c. C670T, p.R224W), but no mutation was found in the healthy skin and peripheral blood sample of the index patient, or in the blood samples of her parents and sibling. PCR-mediated Sanger sequencing of DNA derived from lesional skin sample of the index patient verified KRAS mutation, but not PRKRIR (c.A1674T, p.R558S) and RRP7A (c. C670T, p.R224W). None of the 3 mutations was found in Sanger sequencing in skin lesions of 60 other cases of nevus sebaceous patients.

Conclusions

Our findings show the relevance of KRAS mutation to LNSS, providing new clues in understanding related genetic heterogeneity which could aid genetic counselling for LNSS patients.

Treatment of the nevus sebaceous of Jadasson by a copper vapor laser

Introduction. Nevus sebaceous of Jadassohn (synonym: nevus of the sebaceous glands) (NSG) presents the congenital malformation of the skin with possible transformation into benign or malignant tumors during the adolescence or adulthood. Commonly appeared on the scalp or neck NSG is frequently concern with cosmetic problems making patients look for opportunities for its removal. Surgical removal of the NSG is related to an elevated risk of scarring. Using ablative lasers has proven to be effective in the removal of small NSG. However, the removal of medium and large NSG with ablative lasers was reported to be linked with a high risk of scarring and recurrence. The removal of the medium-sized NSG with a copper vapor laser (CVL) is described here for the first time. Case report and procedure. Laser removal of NSG (linear sized of 27 mm) was performed in a 25-year-old female patient with Fitzpatrick skin type II during eight CVL treatments. Laser settings were selected as follows: the average power of 1 W at the power ratio of 3:2 radiation at a wavelength of 511 and 578 nm. Pulse duration 20 nanoseconds, reprate 16.6 kHz, exposure duration 200 ms, and the light spot's diameter on the skin 1 mm. Results. After 8 procedures, the skin in the area of the removed NSG acquired a natural color and appearance. During 24 months of follow-up, there was no hyperpigmentation or signs of scars in the irradiated area. No relapses were observed for 24 months after the CVL removal of NSG. Conclusion. The application of non-ablative CVL removal of NSG ensured a desired cosmetic result without side effects.

Eccrine Poroma Arising within Nevus Sebaceous

Secondary neoplasms in nevus sebaceous can develop during adolescence and adulthood. Trichoblastoma and syringocystadenoma papilliferum are the most common benign neoplasms, but poroma is rarely reported. A 28-year-old female presented with an asymptomatic mass on the scalp. She has had a hairless lesion on the scalp since birth. A soft mass developed on that lesion four years prior. Physical examination revealed a localized 1 cm×2.5 cm-sized brownish, verrucous-surfaced plaque with a 1 cm×1 cm-sized pedunculated erythematous tumor on the scalp. We performed skin biopsy on both the plaque and tumor lesions. The histopathological findings demonstrated the plaque lesion consistent with nevus sebaceous and the tumor lesion consistent with eccrine poroma. Surgical mass excision was performed. The patient was eventually diagnosed with eccrine poroma arising within nevus sebaceous. To the best of our knowledge, there are only six reported cases on poroma arising within nevus sebaceous. Although rarely documented in the literature, it should be considered as a secondary neoplasm within nevus sebaceous.