Clinical and radiological features in young individuals with nevoid basal cell carcinoma syndrome

Macrocephaly and Finger Changes: A Narrative Review

Macrocephaly, characterized by an abnormally large head circumference, often co-occurs with distinctive finger changes, presenting a diagnostic challenge for clinicians. This review aims to provide a current synthetic overview of the main acquired and genetic etiologies associated with macrocephaly and finger changes. The genetic cause encompasses several categories of diseases, including bone marrow expansion disorders, skeletal dysplasias, ciliopathies, inherited metabolic diseases, RASopathies, and overgrowth syndromes. Furthermore, autoimmune and autoinflammatory diseases are also explored for their potential involvement in macrocephaly and finger changes. The intricate genetic mechanisms involved in the formation of cranial bones and extremities are multifaceted. An excess in growth may stem from disruptions in the intricate interplays among the genetic, epigenetic, and hormonal factors that regulate human growth. Understanding the underlying cellular and molecular mechanisms is important for elucidating the developmental pathways and biological processes that contribute to the observed clinical phenotypes. The review provides a practical approach to delineate causes of macrocephaly and finger changes, facilitate differential diagnosis and guide for the appropriate etiological framework. Early recognition contributes to timely intervention and improved outcomes for affected individuals.

Soft Tissue Calcifications in the Head and Neck Region

This article provides an overview of the soft tissue calcifications in the head and neck region as noted on dental imaging, with particular focus on the radiographic appearance of these entities..

Analysis of candidate genes for cleft lip ± cleft palate using murine single-cell expression data

Introduction: Cleft lip ± cleft palate (CL/P) is one of the most common birth defects. Although research has identified multiple genetic risk loci for different types of CL/P (i.e., syndromic or non-syndromic forms), determining the respective causal genes and understanding the relevant functional networks remain challenging. The recent introduction of single-cell RNA sequencing (scRNA-seq) has provided novel opportunities to study gene expression patterns at cellular resolution. The aims of our study were to: (i) aggregate available scRNA-seq data from embryonic mice and provide this as a resource for the craniofacial community; and (ii) demonstrate the value of these data in terms of the investigation of the gene expression patterns of CL/P candidate genes. Methods and Results: First, two published scRNA-seq data sets from embryonic mice were re-processed, i.e., data representing the murine time period of craniofacial development: (i) facial data from embryonic day (E) E11.5; and (ii) whole embryo data from E9.5-E13.5 from the Mouse Organogenesis Cell Atlas (MOCA). Marker gene expression analyses demonstrated that at E11.5, the facial data were a high-resolution representation of the MOCA data. Using CL/P candidate gene lists, distinct groups of genes with specific expression patterns were identified. Among others we identified that a co-expression network including Irf6, Grhl3 and Tfap2a in the periderm, while it was limited to Irf6 and Tfap2a in palatal epithelia, cells of the ectodermal surface, and basal cells at the fusion zone. The analyses also demonstrated that additional CL/P candidate genes (e.g., Tpm1, Arid3b, Ctnnd1, and Wnt3) were exclusively expressed in Irf6+ facial epithelial cells (i.e., as opposed to Irf6- epithelial cells). The MOCA data set was finally used to investigate differences in expression profiles for candidate genes underlying different types of CL/P. These analyses showed that syndromic CL/P genes (syCL/P) were expressed in significantly more cell types than non-syndromic CL/P candidate genes (nsCL/P). Discussion: The present study illustrates how scRNA-seq data can empower research on craniofacial development and disease.

Case report of bilateral ovarian fibromas associated with de novo germline variants in PTCH1 and SMARCA4

Background

Ovarian sex cord‐stromal tumors (OSCTs) are rare ovarian tumors that can develop from sex cord, stromal cells, or both. OSCTs can be benign or malignant. Bilateral and/or unilateral ovarian fibromas, a type of OSCT of the stromal cells, have been reported in individuals diagnosed with nevoid basal cell carcinoma syndrome (NBCCS). Calcified ovarian fibromas have been reported in 15–25% of individuals diagnosed with NBCCS while 75% of those cases occur bilaterally. The average age at diagnosis of OSCT/ovarian fibromas in patients with NBCSS is in the second to third decade compared with age 50 in the general population. Ovarian tumors are rare in pediatric populations.

Methods

The patient is a 5‐year‐old female diagnosed with bilateral ovarian fibromas at age 4. Multigene panel for the patient and subsequent targeted molecular evaluation of parents were completed. Histological evaluations on the surgically resected ovaries were performed for microscopic characterization of fibromas.

Results

Germline testing identified de novo heterozygous novel likely pathogenic variants in PTCH1 gene, exon 12 deletion, and an SMARCA4 splicing variant c.2002‐1G > A. Microscopic examination of bilateral tumors was consistent with an ovarian fibroma.

Conclusions

To our knowledge, this is the first report of bilateral benign ovarian fibroma in a child with a diagnosis of nevoid basal cell carcinoma syndrome (NBCCS) with a potential predisposition to Rhabdoid Tumor Predisposition Syndrome (RTPS).

Nevoid basal cell carcinoma syndrome: a case report and literature review

BACKGROUND

Nevoid basal cell carcinoma syndrome (NBCCS) is a rare genetic disorder associated with basal cell carcinomas (BCC), skeletal anomalies, and jaw cysts, and a number of ocular abnormalities. We describe a case of a 12-year-old boy diagnosed with NBCCS found to have several ophthalmic manifestations including a myelinated retinal nerve fiber. We conducted a literature review targeting the ocular and systemic manifestations of NBCCS, with a focus on the ophthalmic findings that have not been well characterized.

MATERIALS AND METHODS

We conducted a literature search from 1960 to 2021 utilizing specific keywords and criteria and excluded non-clinical articles. A total of 46 articles were ultimately used for the literature review.

RESULTS

In NBCCS, BCCs typically present before the age of 30 and gradually become numerous. Certain ocular features, less common in the general population, are much more common with NBCCS. Depending on the study, prevalence of these features in patients with NBCCS ranges from 26-80% for hypertelorism and 7-36% for myelinated retinal nerve fiber layer. Prevalence of nystagmus in patients with NBCCS was found to be approximately 6%. Systemic findings such as bilamellar calcification of the falx cerebri, palmar pits, and odontogenic keratocysts (OKCs) are also prevalent.

CONCLUSION

NBCCS may affect numerous organ systems, and thus requires a multidisciplinary team to manage. BCCs and jaw cysts are commonly occurring clinical features that have various surgical excisional options. The ocular anomalies of NBCCS are individually rare, and certain anomalies may present in the amblyogenic period of development and contribute to visual impairment.

Basal cell nevus syndrome: an update on clinical findings

Basal cell nevus syndrome, also known as Gorlin-Goltz syndrome, is a rare autosomal dominant disorder caused by mutations in the hedgehog signaling pathway, mainly in PTCH1. This pathway is involved in embryogenesis and tumorigenesis, and the loss of function of PTCH1 protein produces an aberrant increase in the hedgehog signaling pathway activity. Basal cell nevus syndrome is characterized by tumor predisposition, particularly with the development of multiple basal cell carcinomas at an early age, along with odontogenic keratocysts, palmoplantar pits, skeletal abnormalities, and an increased risk of medulloblastoma. Diagnosis is clinical, with gene mutation analysis confirming the suspicion. The striking phenotypic variability of the syndrome may lead to a delayed diagnosis, making it an uncommon but important entity to recognize. A high index of suspicion and an early diagnosis is crucial for prevention, surveillance, and the prompt establishment of multidisciplinary medical care.

Diagnostic Approach to Macrocephaly in Children

Macrocephaly affects up to 5% of the pediatric population and is defined as an abnormally large head with an occipitofrontal circumference (OFC) >2 standard deviations (SD) above the mean for a given age and sex. Taking into account that about 2-3% of the healthy population has an OFC between 2 and 3 SD, macrocephaly is considered as "clinically relevant" when OFC is above 3 SD. This implies the urgent need for a diagnostic workflow to use in the clinical setting to dissect the several causes of increased OFC, from the benign form of familial macrocephaly and the Benign enlargement of subarachnoid spaces (BESS) to many pathological conditions, including genetic disorders. Moreover, macrocephaly should be differentiated by megalencephaly (MEG), which refers exclusively to brain overgrowth, exceeding twice the SD (3SD-"clinically relevant" megalencephaly). While macrocephaly can be isolated and benign or may be the first indication of an underlying congenital, genetic, or acquired disorder, megalencephaly is most likely due to a genetic cause. Apart from the head size evaluation, a detailed family and personal history, neuroimaging, and a careful clinical evaluation are crucial to reach the correct diagnosis. In this review, we seek to underline the clinical aspects of macrocephaly and megalencephaly, emphasizing the main differential diagnosis with a major focus on common genetic disorders. We thus provide a clinico-radiological algorithm to guide pediatricians in the assessment of children with macrocephaly.

Congenital Hypogonadotropic Hypogonadism with Anosmia and Gorlin Features Caused by a PTCH1 Mutation Reveals a New Candidate Gene for Kallmann Syndrome

BACKGROUND

Two loci (CHD7 and SOX10) underlying Kallmann syndrome (KS) were discovered through clinical and genetic analysis of CHARGE and Waardenburg syndromes, conditions that include congenital anosmia caused by olfactory bulb (CA/OBs) defects and congenital hypogonadotropic hypogonadism (CHH). We hypothesized that other candidate genes for KS could be discovered by analyzing rare syndromes presenting with these signs. Study Design, Size, Duration: We first investigated a family with Gorlin-Goltz syndrome (GGS) in which affected members exhibited clinical signs suggesting KS. Participants/Materials, Methods: Proband and family members underwent detailed clinical assessment. The proband received detailed neuroendocrine evaluation. Genetic analyses included sequencing the PTCH1 gene at diagnosis, followed by exome analyses of causative or candidate KS/CHH genes, in order to exclude contribution to the phenotypes of additional mutations. Exome analyses in additional 124 patients with KS/CHH probands with no additional GGS signs.

RESULTS

The proband exhibited CA, absent OBs on magnetic resonance imaging, and had CHH with unilateral cryptorchidism, consistent with KS. Pulsatile Gonadotropin-releasing hormone (GnRH) therapy normalized serum gonadotropins and increased testosterone levels, supporting GnRH deficiency. Genetic studies revealed 3 affected family members harbor a novel mutation of PTCH1 (c.838G> T; p.Glu280*). This unreported nonsense deleterious mutation results in either a putative truncated Ptch1 protein or in an absence of translated Ptch1 protein related to nonsense mediated messenger RNA decay. This heterozygous mutation cosegregates in the pedigree with GGS and CA with OBs aplasia/hypoplasia and with CHH in the proband suggesting a genetic linkage and an autosomal dominant mode of inheritance. No pathogenic rare variants in other KS/CHH genes cosegregated with these phenotypes. In additional 124 KS/CHH patients, 3 additional heterozygous, rare missense variants were found and predicted in silico to be damaging: p.Ser1203Arg, p.Arg1192Ser, and p.Ile108Met.

CONCLUSION

This family suggests that the 2 main signs of KS can be included in GGS associated with PTCH1 mutations. Our data combined with mice models suggest that PTCH1 could be a novel candidate gene for KS/CHH and reinforce the role of the Hedgehog signaling pathway in pathophysiology of KS and GnRH neuron migration.

Identification of rare PTCH1 nonsense variant causing orofacial cleft in a Chinese family and an up-to-date genotype-phenotype analysis

The Patched 1 (PTCH1) gene encodes a membrane receptor involved in the Hedgehog (Hh) signaling pathway, an abnormal state of which may result in congenital defects or human tumors. In this study, we conducted whole-exome sequencing on a three-generation Chinese family characterized with variable penetrance of orofacial clefts. A rare heterozygous variant in the PTCH1 gene (c.2833C > T p.R945X) was identified as a disease-associated mutation. Structural modeling revealed a truncation starting from the middle of the second extracellular domain of PTCH1 protein. This may damage its ligand recognition and sterol transportation abilities, thereby affecting the Hh signaling pathway. Biochemical assays indicated that the R945X protein had reduced stability compared to the wild-type in vitro. In addition, we reviewed the locations and mutation types of PTCH1 variants in individuals with clefting phenotypes, and analyzed the associations between clefts and locations or types of variants within PTCH1. Our findings provide further evidence that PTCH1 variants result in orofacial clefts, and contributed to genetic counseling and clinical surveillance in this family.

Recurrence of odontogenic keratocysts and possible prognostic factors: Review of 455 patients

BACKGROUND

To describe epidemiological features of 565 Chinese patients with odontogenic keratocysts (OKC), to investigate possible prognostic factors related to recurrence, and to analyse features of recurrent OKC (rOKC).

MATERIAL AND METHODS

A retrospective chart review of 565 cases of OKC treated between 2003 and 2015 was undertaken. The probability of recurrence related to prognostic factors including large size, cortical perforation combined with involved teeth in the lumen of the cyst, inflammation, sites of the involved lesion, sex, and daughter cyst variables were analysed. The subsequent relapse of each OKC was compared.

RESULTS

Patients ranged in age from 7 to 81 years (mean age, 28.4 years) and, of those affected, 66.9% were male and 33.1% were female. Mandibular OKC occurred in 63.01% and 36.99% occurred in the maxilla, 80.53% of patients had non-rOKC, 10.44% rOKC, and 9.03% had multiple OKC lesions. Enucleation with preservation of the involved teeth in the cystic lesion combined with cortical perforation was statistically associated with high recurrence rate, as were daughter cysts, and multilocular lesions. The number of recurrences and the average time (in years) to relapse decreased from the first relapse of OKC to the third relapse, and the difference was significant (P<.05).

CONCLUSIONS

Preservation of the involved teeth combined with cortical perforation appeared to be a potential prognostic factor associated with high recurrence. The follow-up evaluation period for rOKC with ≥ 2 previous treatments should be shorter than for first-time rOKC. The decreasing average duration (years postoperatively) to relapse was related to the number of rOKCs, timing of relapse, and rOKC type.

Co-occurrence of mutations in FOXP1 and PTCH1 in a girl with extreme megalencephaly, callosal dysgenesis and profound intellectual disability

Heterozygous disruptions in FOXP1 are responsible for developmental delay, intellectual disability and speech deficit. Heterozygous germline PTCH1 disease-causing variants cause Gorlin syndrome. We describe a girl with extreme megalencephaly, developmental delay and severe intellectual disability. Dysmorphic features included prominent forehead, frontal hair upsweep, flat, wide nasal bridge, low-set, abnormally modelled ears and post-axial cutaneous appendages on the hands. Brain MRI showed partial agenesis of the corpus callosum and widely separated leaves of the septum pellucidum. Exome sequencing of a gene set representing a total of 4813 genes with known relationships to human diseases revealed an already known heterozygous de novo nonsense disease-causing variant in FOXP1 (c.1573C>T, p.Arg525Ter) and a heterozygous novel de novo frameshift nonsense variant in PTCH1 (c.2834delGinsAGATGTTGTGGACCC, p.Arg945GlnfsTer22). The composite phenotype of the patient seems to be the result of two monogenic diseases, although more severe than described in conditions due to disease-causing variants in either gene.

Germline SUFU mutation carriers and medulloblastoma: clinical characteristics, cancer risk, and prognosis

Background

Germline mutations of suppressor of fused homolog (SUFU) predispose to sonic hedgehog (SHH) medulloblastoma. Germline SUFU mutations have been reported in nevoid basal cell carcinoma syndrome (NBCCS), but little is known about the cancer risk and clinical spectrum.

Methods

We performed a retrospective review of all patients with medulloblastoma and a germline SUFU mutation in France.

Results

Twenty-two patients from 17 families were identified with medulloblastoma and a germline SUFU mutation (median age at diagnosis: 16.5 mo). Macrocrania was present in 20 patients, but only 5 met the diagnostic criteria for NBCCS. Despite treatment with surgery and chemotherapy, to avoid radiotherapy in all patients except one, the outcome was worse than expected for SHH medulloblastoma, due to the high incidence of local relapses (8/22 patients) and second malignancies (n = 6 in 4/22 patients). The 5-year progression-free survival and overall survival rates were 42% and 66%. Mutations were inherited in 79% of patients, and 34 additional SUFU mutation carriers were identified within 14 families. Medulloblastoma penetrance was incomplete, but higher than in Patched 1 (PTCH1) mutation carriers. Besides medulloblastoma, 19 other tumors were recorded among the 56 SUFU mutation carriers, including basal cell carcinoma (BCC) in 2 patients and meningioma in 3 patients.

Conclusion

Germline SUFU mutations strongly predispose to medulloblastoma in the first years of life, with worse prognosis than usually observed for SHH medulloblastoma. The clinical spectrum differs between SUFU and PTCH1 mutation carriers, and BCC incidence is much lower in SUFU mutation carriers. The optimal treatment of SUFU mutation-associated medulloblastoma has not been defined.

An Unusual Case of an Odontogenic Keratocyst Associated With an Ungrafted Alveolar Cleft: A Case Report and Review of the Literature

We describe an unusual case of an odontogenic keratocyst (OKC) associated with an ungrafted left-sided alveolar cleft in a 10-year-old male patient. There is no previous report in the literature of OKC or other dental cysts associated with an alveolar cleft. We discuss the management of the OKC prior to secondary bone grafting and present this case to highlight the difficulty in the management of OKC concurrent with grafting of the alveolar cleft site, the proximity of unerupted permanent teeth, and possible treatment modalities.

Blue light versus red light for photodynamic therapy of basal cell carcinoma in patients with Gorlin syndrome: A bilaterally controlled comparison study

BACKGROUND

Photodynamic therapy (PDT) is a non-scarring alternative for treating basal cell carcinoma (BCC) in patients with Basal Cell Nevus Syndrome (BCNS), also known as Gorlin syndrome. In Europe, red light (635 nm) is the predominant source for PDT, whereas in the United States blue light (400 nm) is more widely available. The objective of this study was to conduct a head-to-head comparison of blue light and red light PDT in the same BCNS patients.

METHODS

In a pilot study of three patients with 141 BCC lesions, 5-aminolevulinate (20% solution) was applied to all tumors. After 4 h, half of the tumors were illuminated with blue light and the remainder with red light. To ensure safety while treating this many tumors simultaneously, light doses were escalated gradually. Six treatments were administered in three biweekly sessions over 4 months, with a final evaluation at 6 months. Tumor status was documented with high-resolution photographs. Persistent lesions were biopsied at 6 months.

RESULTS

Clearance rates after blue light (98%) were slightly better than after red light (93%), with blue light shown to be statistically non-inferior to red light. Eight suspicious lesions were biopsied, 5 after red light (5/5 were BCC) and 3 after blue light (1 was BCC). Blue light PDT was reportedly less painful.

CONCLUSION

Blue light and red light PDT appear to be equally safe and perhaps equally effective for treating BCC tumors in BCNS patients. Further studies to evaluate long-term clearance after blue light PDT are needed.

Gorlin Syndrome

Gorlin syndrome is a rare autosomal dominant disease caused by mutations in the sonic hedgehog signaling pathway. Of particular importance is the PTCH1 gene. The disease is characterized by the development of multiple basal cell carcinomas at young ages. These tumors may present with other skin manifestations such as palmoplantar pits and with extracutaneous manifestations such as odontogenic keratocysts and medulloblastoma. Although the dermatologist may be key for recognizing clinical suspicion of the syndrome, a multidisciplinary team is usually necessary for diagnosis, treatment, and follow-up. Skin treatment may be complicated due to the large number of basal cell carcinomas and the extent of involvement. In recent years, new drugs that inhibit targets in the sonic hedgehog pathway have been developed. Although these agents appear promising options for patients with Gorlin syndrome, their efficacy is limited by adverse effects and the development of resistance.

Novel clinical and molecular findings in Spanish patients with naevoid basal cell carcinoma syndrome

BACKGROUND

Naevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by developmental alterations and multiple basal cell carcinomas. Mutations in PTCH1, which encodes a membrane receptor for Sonic Hedgehog, are associated with the development of the disease. Most of them produce a truncated protein, which is unable to suppress Smoothened protein and continuously activates the downstream pathway.

OBJECTIVES

We aimed to characterize 22 unrelated Spanish patients with NBCCS, the largest cohort with Gorlin syndrome reported to date in Spain.

METHODS

Genomic analysis of PTCH1 was performed in patients with NBCCS and controls, and mutations were analysed using bioinformatics tools.

RESULTS

We report for the first time two young patients, one each with uterus didelphys and ganglioneuroma, within the context of NBCCS. One patient showing a severe phenotype of the disease had developed basal cell carcinomas since childhood. Sanger sequencing of PTCH1 in this cohort identified 17 novel truncating mutations (11 frameshift, five nonsense and one mutation affecting an exon-intron splice site) and two novel missense mutations that were predicted to be pathogenic. The patients showed great clinical variability and inconsistent genotype-phenotype correlation, as seen in relatives carrying similar mutations.

CONCLUSIONS

This study contributes to increase the pool of clinical manifestations of NBCCS, as well as increasing the number of pathogenic mutations identified in PTCH1 predisposing to the condition. The inconsistencies found between phenotype and genotype suggest the involvement of other modifying factors, genetic, epigenetic or environmental.

Male fertility and skin diseases

Male fertility can be affected by a variety of organs diseases, including the skin. Several genodermatoses affect the skin and several other organs including the male reproductive system, commonly in the form of cryptorchidism and hypogonadism. The most relevant syndromes are associated with dyschromias, such as deSanctis-Cacchione, poikiloderma congenital, LEOPARD, and H syndrome; others with ichthyosis, such as Rud, and trichothiodystrophy; or a group of unrelated genodermatoses, such as ablepharon macrostomia, Coffin-Siris, Gorlin-Goltz, and Werner. Acquired skin diseases may also affect male fertility usually in the form of orchitis or epididymal obstruction or androgen antagonists. These include infections (leprosy and HIV), autoimmune (erythema nodosum leprosum), granulomatous (sarcoidosis, Langerhans cell histiocytosis), nutritional deficiency (zinc), and malignancy. Several therapeutics of skin diseases are notorious for their effects on male fertility, most notably are the cytotoxic drugs (methotrexate), irradiation, and antiandrogens (spironolactone, finasteride). Although the prevalence of these skin diseases is low, the associated male infertility represents a challenge due to the difficulty of its management. Clinical management of the skin diseases should include consideration of their effects not only on the diseases but also on the male reproductive system.

Hedgehog receptor function during craniofacial development

The Hedgehog signalling pathway plays a fundamental role in orchestrating normal craniofacial development in vertebrates. In particular, Sonic hedgehog (Shh) is produced in three key domains during the early formation of the head; neuroectoderm of the ventral forebrain, facial ectoderm and the pharyngeal endoderm; with signal transduction evident in both ectodermal and mesenchymal tissue compartments. Shh signalling from the prechordal plate and ventral midline of the diencephalon is required for appropriate division of the eyefield and forebrain, with mutation in a number of pathway components associated with Holoprosencephaly, a clinically heterogeneous developmental defect characterized by a failure of the early forebrain vesicle to divide into distinct halves. In addition, signalling from the pharyngeal endoderm and facial ectoderm plays an essential role during development of the face, influencing cranial neural crest cells that migrate into the early facial processes. In recent years, the complexity of Shh signalling has been highlighted by the identification of multiple novel proteins that are involved in regulating both the release and reception of this protein. Here, we review the contributions of Shh signalling during early craniofacial development, focusing on Hedgehog receptor function and describing the consequences of disruption for inherited anomalies of this region in both mouse models and human populations.

A systematic review of the literature of nevoid basal cell carcinoma syndrome affecting East Asians and North Europeans

OBJECTIVE

To compare, by systematic review, North European and East Asian consecutive case series of nevoid basal cell carcinoma syndrome (NBCCS).

STUDY DESIGN

A systematic review of the literature was performed for all consecutive case series of NBCCS, which included keratocystic odontgenic tumors (KCOTs) arising in North European and East Asian communities. The clinical and radiologically apparent features were identified and synthesized, and a meta-analysis was performed.

RESULTS

East Asian reports were significantly more "proband only" compared with North European reports. Significant differences between these 2 communities were observed for 5 of the 6 major features and 11 of the 27 minor features. With regard to the major NBCCS features, the North Europeans displayed significantly more frequent basal cell carcinomas, calcified falx cerebri, palmar and plantar pits, and a family history, whereas the East Asians displayed KCOTs significantly more frequently. With regard to minor features, East Asians displayed significantly more frequent cleft lips and palates and hypertelorism.

CONCLUSIONS

East Asians displayed multiple KCOTs and cleft lips and palates more frequently compared with North Europeans.

Basal cell carcinoma: a comprehensive review for the radiologist

OBJECTIVE. Basal cell carcinoma (BCC) is the most common malignancy in the United States. The purpose of this article is to provide a comprehensive description of the clinicopathologic features, diagnostic workup, staging, treatment, and follow-up of BCC. CONCLUSION. Radiology plays an important role in the evaluation and staging of locally advanced and metastatic BCC. MRI is the modality of choice for assessing perineural disease and is equivalent or superior to CT for evaluating bony involvement. CT and PET/CT are used to evaluate metastatic disease.

Basal cell nevus syndrome or Gorlin syndrome

Basal cell nevus syndrome (BCNS) or Gorlin syndrome is a rare neurocutaneous syndrome sometimes known as the fifth phacomatosis, inherited in autosomal dominant fashion with complete penetrance and variable expressivity. Gorlin syndrome is characterized by development of multiple basal cell carcinomas (BCCs), jaw cysts, palmar or plantar pits, calcification of falx cerebri, various developmental skeletal abnormalities such as bifid rib, hemi- or bifid vertebra and predisposition to the development of various tumors. BCNS is caused by a mutation in the PTCH1 gene localized to 9q22.3. Its estimated prevalence varies between 1/55600 and 1/256000 with an equal male to female ratio. The medulloblastoma variant seen in Gorlin syndrome patients is of the desmoplastic type, characteristically presenting during the first 3 years of life. Therefore, children with desmoplastic medulloblastoma should be carefully screened for other features of BCNS. Radiation therapy for desmoplastic medulloblastoma should be avoided in BCNS patients as it may induce development of invasive BCCs and other tumors in the skin area exposed to radiation. This syndrome is a multisystem disorder so involvement of multiple specialists with a multimodal approach to detect and treat various manifestations at early stages will reduce the long-term sequelae and severity of the condition. Life expectancy is not significantly altered but morbidity from complications and cosmetic scarring can be substantial.

Gorlin syndrome (nevoid basal cell carcinoma syndrome): update and literature review

Gorlin syndrome, also called nevoid basal cell carcinoma syndrome, is an autosomal dominant neurocutaneous disease characterized by developmental anomalies such as palmar pits and rib anomaly, and tumorigenesis such as medulloblastoma and basal cell carcinoma. This syndrome is mainly caused by a mutation of PTCH1, a human homologue of Drosophila patched, including frameshift, missense, or nonsense mutations. Genotype-phenotype correlation has not been established. PTCH1 is a member of hedgehog signaling, which is a highly conserved pathway in vertebrates, composed of hedgehog, SMO, and GLI proteins as well as PTCH1. Given that hedgehog signaling regulates cell growth and development, disorder of this pathway gives rise to not only developmental anomalies but also diverse tumors such as those seen in Gorlin syndrome. We recently reported, for the first time, a nationwide survey of Gorlin syndrome in Japan, noting that the frequency was 1/235,800 in the Japanese population, and that the frequency of basal cell carcinomas was significantly lower in Japan than in the USA and Europe, suggesting that ethnicity and genetic background contribute to these differences. Given that many clinical trials using newly discovered molecular inhibitors are still ongoing, these agents should become the new therapeutic options for hedgehog pathway-dependent tumors in patients with or without Gorlin syndrome.

The Ptch1(DL) mouse: a new model to study lambdoid craniosynostosis and basal cell nevus syndrome-associated skeletal defects

Mouse models provide valuable opportunities for probing the underlying pathology of human birth defects. By using an N-ethyl-N-nitrosourea-based screen for recessive mutations affecting craniofacial anatomy, we isolated a mouse strain, Dogface-like (DL), with abnormal skull and snout morphology. Examination of the skull indicated that these mice developed craniosynostosis of the lambdoid suture. Further analysis revealed skeletal defects related to the pathology of basal cell nevus syndrome (BCNS) including defects in development of the limbs, scapula, ribcage, secondary palate, cranial base, and cranial vault. In humans, BCNS is often associated with mutations in the Hedgehog receptor PTCH1 and genetic mapping in DL identified a point mutation at a splice donor site in Ptch1. By using genetic complementation analysis we determined that DL is a hypomorphic allele of Ptch1, leading to increased Hedgehog signaling. Two aberrant transcripts are generated by the mutated Ptch1(DL) gene, which would be predicted to reduce significantly the levels of functional Patched1 protein. This new Ptch1 allele broadens the mouse genetic reagents available to study the Hedgehog pathway and provides a valuable means to study the underlying skeletal abnormalities in BCNS. In addition, these results strengthen the connection between elevated Hedgehog signaling and craniosynostosis.