Frequent beta-catenin mutations in juvenile nasopharyngeal angiofibromas

Utility of LEF1 to differentiate desmoid fibromatosis from its histologic mimics

Diagnosis of desmoid-type fibromatosis (DF) may be challenging on biopsy due to morphologic overlap with reactive fibrosis (scar) and other uniform spindle cell neoplasms. Evaluation of nuclear β-catenin, a surrogate of Wnt pathway activation, is often difficult in DF due to weak nuclear expression and high background membranous/cytoplasmic staining. Lymphoid enhancer-factor 1 (LEF1) is a recently characterized effector partner of β-catenin which activates the transcription of target genes. We investigated the performance of LEF1 and β-catenin immunohistochemistry in a retrospective series of 156 soft tissue tumors, including 35 DF, 3 superficial fibromatosis, and 121 histologic mimics (19 soft tissue perineurioma, 8 colorectal perineurioma, 4 intraneural perineurioma, 26 scars, 23 nodular fasciitis, 6 low-grade fibromyxoid sarcomas, 6 angioleiomyomas, 5 neurofibromas, 5 dermatofibrosarcoma protuberans, 3 low-grade myofibroblastic sarcomas, 3 synovial sarcomas, 3 inflammatory myofibroblastic tumors, 2 schwannomas, and 1 each of Gardner-associated fibroma, radiation-associated spindle cell sarcoma, sclerotic fibroma, dermatofibroma, and glomus tumor). LEF1 expression was not only seen in 33/35 (94%) of DF but also observed in 19/23 (82%) nodular fasciitis, 7/19 (37%) soft tissue perineurioma, 2/3 (66%) synovial sarcoma, and 6/26 (23%) scar, as well as in 1 radiation-associated spindle cell sarcoma. The sensitivity and specificity of LEF1 IHC for diagnosis of DF were 94% and 70%, respectively. By comparison, β-catenin offered similar sensitivity, 94%, but 88% specificity. Positivity for LEF1 and β-catenin in combination showed sensitivity of 89%, lower than the sensitivity of β-catenin alone (94%); however, the combination of both LEF1 and β-catenin improved specificity (96%) compared to the specificity of β-catenin alone (88%). Although LEF1 has imperfect specificity in isolation, this stain has diagnostic utility when used in combination with β-catenin.

CTNNB1 mutation-driven hybrid tumor: desmoid fibromatosis with an unusual associated epithelioid component arising in association with a neuromuscular choristoma

CTNNB1 mutations play important roles in the development of soft tissue tumors, such as desmoid fibromatosis (DF), sinonasal tract angiofibroma, sinonasal glomangiopericytoma, intranodal palisaded myofibroblastoma, neuromuscular choristoma (NMC), and the recently reported pseudoendocrine sarcoma. Here, we report a unique hybrid soft tissue tumor with classic DF, unusual epithelioid component, and NMC in a 23-year-old female. The classic DF and NMC and the unusual epithelioid component and NMC were locally intermixed and closely related to each other. Immunohistochemically, the DF, unusual epithelioid component, and NMC exhibited nuclear positivity for β-catenin to varying degrees. More critically, all of the above components harbored identical CTNNB1 p.Ser45Pro missense mutations. To the best of our knowledge, this is the only reported CTNNB1 mutation-driven hybrid tumor with DF, unusual epithelioid component, and NMC. The present case further confirmed that CTNNB1-mutational soft tissue tumors are highly heterogeneous, but the morphological spectrum is wide and consecutive.

Integrated Molecular and Histological Insights for Targeted Therapies in Mesenchymal Sinonasal Tract Tumors

PURPOSE OF REVIEW

This review aims to provide a comprehensive overview of mesenchymal sinonasal tract tumors (STTs), a distinct subset of STTs. Despite their rarity, mesenchymal STTs represent a unique clinical challenge, characterized by their rarity, often slow progression, and frequently subtle or overlooked symptoms. The complex anatomy of the sinonasal area, which includes critical structures such as the orbit, brain, and cranial nerves, further complicates surgical treatment options. This underscores an urgent need for more advanced and specialized therapeutic approaches.

RECENT FINDINGS

Advancements in molecular diagnostics, particularly in next-generation sequencing, have significantly enhanced our understanding of STTs. Consequently, the World Health Organization has updated its tumor classification to better reflect the distinct histological and molecular profiles of these tumors, as well as to categorize mesenchymal STTs with greater accuracy. The growing understanding of the molecular characteristics of mesenchymal STTs opens new possibilities for targeted therapeutic interventions, marking a significant shift in treatment paradigms. This review article concentrates on mesenchymal STTs, specifically addressing sinonasal tract angiofibroma, sinonasal glomangiopericytoma, biphenotypic sinonasal sarcoma, and skull base chordoma. These entities are marked by unique histopathological and molecular features, which challenge conventional treatment approaches and simultaneously open avenues for novel targeted therapies. Our discussion is geared towards delineating the molecular underpinnings of mesenchymal STTs, with the objective of enhancing therapeutic strategies and addressing the existing shortcomings in the management of these intricate tumors.

Diagnostic implications of Gardner Syndrome, case report of a familial adenomatous polyposis (FAP) variant, for eye care professionals

INTRODUCTION

Gardner Syndrome (GS) is a variant of Familial Adenomatous Polyposis (FAP). FAP is characterized by several precancerous adenomatous intestinal polyps while GS has additional distinct extraintestinal features such as congenital hypertrophy of retinal epithelium (CHRPE), which we describe here.

PRESENTATION OF CASE

42-year-old male with GS presenting with flashes and floaters observed to have CHRPE-like lesions characteristic of GS.

DISCUSSION

Subtle CHRPE findings differentiate pathological, described in the present case, from non-pathological etiologies and may guide further management.

CONCLUSION

Here we present the signs and symptoms that raise suspicion for GS associated with CHRPE and how to approach management late in the disease presentation.

Spindle Cell Tumors of the Sinonasal Tract: A Diagnostic Update with Focus on Ancillary Workup

Spindle cell neoplasms arising in the head and neck may be challenging to recognize due to their relative rarity. While underlying molecular alterations are increasingly elucidated, testing for these features may not be readily available. In most cases, combinations of key morphologic features and diagnostic immunohistochemical markers can be used to replace molecular diagnostics. Conversely, some molecular alterations and expression of their surrogate biomarkers are not specific for any one entity, and it is important to recognize these to avoid diagnostic pitfalls. In this review, we discuss both old and new spindle cell tumors of the sinonasal tract, with an emphasis on histologic features and clinically relevant immunohistochemical markers serving as surrogate markers for underlying genomic alterations.

Sinonasal Myxoma: A Distinct Entity or a Myxoid Variant of Desmoid Fibromatosis?

Sinonasal myxoma (SNM) is a rare benign mesenchymal tumor that arises in the sinonasal cavity or maxilla and almost exclusively affects young children. Currently, it is considered a specific entity, but its molecular characteristics have not been reported. Lesions diagnosed as SNM and odontogenic myxoma/fibromyxoma (OM/OFM) were identified from the participating institutions, and the clinicopathologic features were recorded. Immunohistochemistry for β-catenin was performed on all cases with available tissue. Next-generation sequencing (NGS) was performed on all SNM cases. Five patients with SNM were identified, including 3 boys and 2 girls with an age range of 20-36 months (mean: 26 months). The tumors were well-defined, centered in the maxillary sinus, surrounded by a rim of woven bone, and composed of a moderately cellular proliferation of spindle cells oriented in intersecting fascicles in a variably myxocollagenous stroma that contained extravasated erythrocytes. Histologically, the tumors resembled myxoid desmoid fibromatosis. Three tested cases showed nuclear expression of β-catenin. In 3 tumors, NGS revealed intragenic deletions of APC exons 5-6, 9 and 15, or 16, respectively, with concurrent loss of the other wild-type copy of APC, predicted to result in biallelic inactivation. The deletions were identical to those that occur in desmoid fibromatosis, and copy-number analysis raised the possibility that they were germline. In addition, one case showed possible deletion of APC exons 12-14, and another case exhibited a CTNNB1 p.S33C mutation. Ten patients with OM/OFM were identified, including 4 women and 6 men (mean age: 42 years). Seven tumors involved the mandible, and 3 the maxilla. Histologically, the tumors differed from SNM, and all cases lacked nuclear expression of β-catenin. These findings suggest that SNM represents a myxoid variant of desmoid fibromatosis that often arises in the maxilla. Because the APC alterations might be germline, genetic testing of the affected patients should be considered.

Update from the 5th Edition of the World Health Organization Classification of Head and Neck Tumors: Nasal Cavity, Paranasal Sinuses and Skull Base

The World Health Organization Classification of Head and Neck Tumours recently published the 5th edition. There are new entities, emerging entities, and significant updates to the taxonomy and characterization of tumor and tumor-like lesions, specifically in this article as it relates to nasal cavity, paranasal sinuses and skull base. Importantly, the number of diagnostic entries has been reduced by creating category-specific chapters for soft tissue, hematolymphoid, melanocytic, neuroectodermal, and metastatic tumors. Bone and salivary gland tumors are also not separately reported in the sinonasal tract, but included in the jaw and salivary gland sections, respectively. Repetition of characteristic entities in each anatomic site was also reduced, instead highlighting only the unique features in each anatomic site. Two new entities (SWI/SNF complex-deficient sinonasal carcinomas and HPV-related multiphenotypic sinonasal carcinoma) will be highlighted in this review, with a discussion of several emerging entities. There is a short description of updated information for all 24 diagnostic entities included in this edition to allow the reader a snapshot of current state of knowledge, but to encourage more investigation and further broaden understanding of these diverse and rare entities.

Neural Crest Stem Cells in Juvenile Angiofibromas

The etiology of juvenile angiofibroma (JA) has been a controversial topic for more than 160 years. Numerous theories have been proposed to explain this rare benign neoplasm arising predominately in adolescent males, focusing mainly on either the vascular or fibrous component. To assess our hypothesis of JA’s being a malformation arising from neural crest cells/remnants of the first branchial arch plexus, we performed immunohistochemical analyses of neural crest stem cells (NCSC) and epithelial-mesenchymal transition (EMT) candidates. Immunoexpression of the NCSC marker CD271^p75 was observed in all investigated JA’s (n = 22), mainly around the pathological vessels. Close to CD271^p75-positive cells, high MMP3-staining was also observed. Additionally, from one JA with sufficient material, RT-qPCR identified differences in the expression pattern of PDGFRβ, MMP2 and MMP3 in MACS^®-separated CD271^p75positive vs. CD271^p75 negative cell fractions. Our results, together with the consideration of the literature, provide evidence that JA’s represent a malformation within the first branchial arch artery/plexus remnants deriving from NCSC. This theory would explain the typical site of tumor origin as well as the characteristic tumor blood supply, whereas the process of EMT provides an explanation for the vascular and fibrous tumor component.

Middle turbinate angiofibroma in an adolescent boy

Bleeding nasal mass in adolescent boys has customarily been attributed to Juvenile nasopharyngeal angiofibroma. However, little is known regarding the extranasopharyngeal origin of angiofibroma, as highlighted in this case report of a 15-year-old boy who presented with recurrent epistaxis and nasal obstruction. On constructing a working diagnosis of nasal haemangioma, the patient was taken up for endoscopic excision under general anaesthesia. Intraoperative endoscopic findings and histopathological examination revealed the diagnosis of middle turbinate angiofibroma, which is an extremely rare extranasopharyngeal angiofibroma. Consequently, this represents the third described case of a juvenile angiofibroma arising from the middle turbinate.

Molecular Alterations in Pediatric Fibroblastic/Myofibroblastic Tumors: An Appraisal of a Next Generation Sequencing Assay in a Retrospective Single Centre Study

BACKGROUND

Pediatric fibroblastic/myofibroblastic tumors (PFMTs) can be challenging to definitively classify. Large case series or diagnostic updates have not been recently published despite identification of molecular alterations that could improve diagnostic accuracy. Our review of the literature found that over two-thirds of the more than 30 types of PFMTs harbor recurrent molecular alterations. We performed an institutional review of PFMTs to highlight limitations of a predominantly morphological classification, and evaluated the utility of a next-generation sequencing assay to aid diagnosis.

METHODS

PFMTs identified over a period of 12 years were reviewed, categorized per the new WHO classification, and tested using the Oncomine Childhood Cancer Research Assay.

RESULTS

Eighty-seven specimens from 58 patients were reviewed; 50 were chosen for molecular analysis, 16 (32%) lacking definitive classification. We identified alterations, some novel, in 33% of assayed cases. Expected alterations were identified for most known diagnoses and mutations were identified in 6 of 16 tumors (38%) that were initially unclassified.

CONCLUSION

We confirmed a significant subset of PFMTs remain difficult to classify using current criteria, and that a combined DNA/RNA assay can identify alterations in many of these cases, improving diagnostic certainty and suggesting a clinical utility for challenging cases.

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.

Loss of CTNNB1 exon 3 in sclerosing angiomatoid nodular transformation of the spleen

Sclerosing angiomatoid nodular transformation (SANT) is a rare vascular lesion of the spleen. Although several hypotheses have been suggested, the etiopathogenesis of SANT remains unknown. It is also unclear whether SANT is a reactive or a neoplastic lesion. Since CTNNB1 (β-catenin gene) exon 3 mutations were frequently detected in some rare fibrovascular lesions, we aimed to investigate the presence of oncogenic CTNNB1 mutations in SANT cases. For this purpose, 7 cases of SANT with typical histopathological features were retrieved. First, the presence of CTNNB1 exon 3 alterations was examined with a recently described immunohistochemistry-based method. Then, the findings were confirmed with polymerase chain reaction (PCR), reverse transcription PCR (RT-PCR), and Sanger sequencing. In all cases, immunochemistry of β-catenin gave a staining pattern that was suggestive of exon 3 alteration; however, no missense mutations were found in any case at the CTNNB1 exon 3 hotspot region. Subsequently, we screened for large interstitial deletions of CTNNB1 exon 3 which revealed short PCR products in three cases. Sequencing confirmed that these cases had large interstitial deletions, resulting in loss of the entire exon 3 of CTNNB1. In the remaining four cases, loss of exon 3 was documented at the cDNA level, although genomic deletion was not identified. These results demonstrate that loss of CTNNB1 exon 3 and stabilization of β-catenin with activation of Wnt signaling pathway might have a significant role in the pathogenesis of SANT. Through this study, we provided important evidence for the neoplastic nature and pathogenesis of this disorder.

Sinonasal haemangiopericytoma- An unusual swelling in the nasal cavity

Sinonasal hemangiopericytoma, also known as glomangiopericytoma (GPC) is a benign perivascular tumor of low malignant potential, with an incidence rate of 0.5-1% of all sinonasal tumors. It often shows local recurrences with invasion to the surrounding bony tissues. It usually arises from the perivascular cells surrounding the capillaries. Etiology of the tumour is uncertain, with few postulated hypothesis like pregnancy, trauma, hypertension and corticosteroid drugs. They have an indolent course and tend to occur most commonly in the adults of seventh decade of life. We present a case report of 55 years old male presenting to the ENT OPD, with complaints of right sided nasal obstruction and repeated episodes of epistaxis since the last 9 months. History and general examination was unremarkable except for anti-hypertensive intake since the last few years. Laboratory investigations showed microcytic hypochromic anaemia, raised absolute eosinophil count of 1500 cells per microliter and positive Hepatitis B surface antigen (HBsAg) in the blood. Rhinoscopic examination showed a reddish brown nodular swelling in the right nasal cavity beneath the middle turbinate and hypertrophy of left nasal mucosa. CT imaging suggested an 18x15 mms, well defined soft tissue mass in the right nasal cavity. Complete resection of the mass with endoscopic surgery was performed. Histopathological examination coupled with immunohistochemistry confirmed the diagnosis of Sinonasal Hemangiopericytoma. This case report stresses upon various differential diagnosis of sinonasal swellings and the importance of considering long term follow up of Sinonasal Hemagiopericytoma.

Mandibular Intraosseous Angiofibroma-A Rare Clinical Entity

Angiofibromas located in the maxillofacial region are rare and almost exclusively occur in adolescent males. These benign tumors are highly vascular, locally invasive, and commonly found in the nasopharyngeal space. In the present report, we describe a very rare case of an intraosseous mandibular angiofibroma in a 23-year-old male patient with histomorphologic and molecular confirmation. This type of tumor occurring in the mandible has been reported previously only once, to the best of our knowledge.

Soft Tissue Special Issue: Fibroblastic and Myofibroblastic Neoplasms of the Head and Neck

Fibroblastic and myofibroblastic neoplasms of the head and neck encompass a group of rare tumor types with often overlapping clinicopathologic features that range in biologic potential from benign to overtly malignant. Even neoplasms with no metastatic potential may provide significant therapeutic challenges in this region due to the unique anatomy of the head and neck. This review will cover the following entities, highlighting important clinical aspects of each neoplasm and then focusing on their characteristic histomorphology, immunophenotype, and molecular alterations: nodular and cranial fasciitis, fibrous hamartoma of infancy, nasopharyngeal angiofibroma, nuchal-type and Gardner fibromas, desmoid fibromatosis, dermatofibrosarcoma protuberans and giant cell fibroblastoma, solitary fibrous tumor, inflammatory myofibroblastic tumor, low-grade myofibroblastic sarcoma, infantile fibrosarcoma, low-grade fibromyxoid sarcoma, and sclerosing epithelioid fibrosarcoma. While some of these neoplasms characteristically arise in the head and neck, others are rarely described in this anatomic region and may therefore be particularly difficult to recognize. Distinction between these entities, however, is crucial, particularly as the molecular pathogenetic basis for these neoplasms are being rapidly elucidated, in some instances allowing for targeted therapeutic approaches.

Soft Tissue Special Issue: Perivascular and Vascular Tumors of the Head and Neck

Perivascular and vascular neoplasms of the head and neck are a rare group of tumors comprising a spectrum of clinical/biologic and histological features. They are frequently diagnostically challenging, due to their morphologic and immunohistochemical overlap. In this review, we summarize the pathology of these neoplasms, discussing morphology, immunohistochemistry, associated genetic findings, and the differential diagnoses.

Salivary ghost cell carcinoma: case report and proposal of a new entity

Various topographically heterogeneous, histologically related groups of basaloid tumours are characterized by ghost cell differentiation with associated CTNNB1 mutations and nuclear β-catenin expression. We describe the unique case of a malignant tumour with ghost cell differentiation in the floor of the mouth, in which clinical, radiological, histological, immunohistological and molecular data altogether strongly indicate classification as a new type of salivary gland carcinoma.

[Sinonasal tumors : News from the WHO with special reference to mesenchymal entities]

The last two decades have seen significant advances in the pathology of sinonasal tract neoplasms. This was the consequence of the availability of several innovative diagnostic tools, which resulted in a dynamic evolution of entities and splitting of newly defined or conceptualized entities and subtypes that have been included in the spectrum of old heterogeneous diseases. Most of these new tumor subtypes have distinctive demographic, clinicopathologic, and biological characteristics with prognostic and therapeutic implications for individual patients. NUT carcinoma (NUT midline carcinoma) was separated from the spectrum of sinonasal undifferentiated carcinoma (SNUC) and is defined by specific recurrent translocation. On the other hand, the recently described SMARCB1-deficient carcinoma (while probably representing a distinctive clinicopathologic entity) remained as a variant in the SNUC spectrum. A new neoplasm in the spectrum of non-keratinizing carcinomas is the human papillomavirus(HPV)-related adenoid-cystic-like sinonasal carcinoma with its distinctive, albeit diverse, morphology. In the group of small round-cell malignancies, adamantinoma-like Ewing sarcoma has been delineated as an important diagnostic pitfall given its prominent epithelial differentiation. Inclusion of the biphenotypic (myoneural) sinonasal sarcoma (BSS) as a low-grade malignancy defined by recurrent PAX3/MAML3-translocation represents an important feature of the new WHO classification given the distinctive biological behavior of this low-grade non-metastasizing rare entity, which has been uniformly misclassified as a peripheral nerve sheath tumor or leiomyosarcoma in the past. Recognition of CTNNB1 mutations and STAT6/NAB2 gene fusions as defining genetic markers for sinonasal hemangio‑/glomangiopericytoma and solitary fibrous tumors, respectively, represents another important achievement in recent years. This review summarizes the new aspects in the WHO classification and also addresses recently described entities that have not been included in the WHO classification.

The Genetic and Molecular Determinants of Juvenile Nasopharyngeal Angiofibroma: A Systematic Review

Objective:

Juvenile nasopharyngeal angiofibroma (JNA) is a rare vascular tumor of unknown etiology. Studies investigating the molecular and genetic determinants of JNA are limited by small sample size and inconsistent approaches. The purpose of this study is to examine all eligible JNA studies in aggregate, applying qualitative analysis to highlight areas of particular relevance, including potential targets for therapeutic intervention.

Methods:

The PubMed, MEDLINE, Embase, Web of Science, Cochrane, and CINAHL databases were screened with inclusion and exclusion criteria applied to all citations. Manuscripts investigating the genetic determinants, histopathogenesis, and heritability of juvenile nasopharyngeal angiofibroma were included. Non-English studies, case reports, and articles focusing on clinical management without original data were excluded. Full text articles were obtained. A qualitative synthesis of data was performed.

Results:

A total of 59 articles met criteria for inclusion. These were divided into 6 categories based on the primary topic or target discussed, (1) steroid hormone receptors, (2) chromosomal abnormalities, (3) growth factors, (4) genetic targets, (5) molecular targets, (6) Wnt cell signaling, and (7) studies that overlapped multiple of the aforementioned categories. Although relatively low n values prevent definitive conclusions to be drawn, a predominance of certain molecular targets such as vascular endothelial growth factor (VEGF) and Wnt/β-catenin pathway intermediaries is apparent.

Conclusions:

Although the etiology of JNA remains elusive, contemporary molecular genetic investigation holds promise for risk stratification and could form the basis of a modernized staging system. A multicenter clinical registry and linked tissue bank would further promote the search for JNA specific biomarkers.

PRRX-NCOA1/2 rearrangement characterizes a distinctive fibroblastic neoplasm

Fibroblastic/myofibroblastic neoplasms represent a broad, and occasionally diagnostically challenging, category of soft tissue neoplasms. A subset of these tumors defy conventional classification. However, with the advent of next-generation sequencing, the identification of disease-defining molecular alterations is gradually improving their subclassification. Following identification of two index cases of a distinctive fibroblastic neoplasm with a fusion gene involving PRRX1 and NCOA1, we performed a retrospective review to further characterize this entity. We identified two additional cases, including one with a fusion between PRRX1 and NCOA2. The average patient age was 38 years, and three patients were female. Two tumors occurred on the neck, and the others involved the groin and thigh. Tumors were centered in the subcutis and ranged from 2.3 to 14.0 cm (average 5.8 cm). Morphologically, they were predominantly hypocellular, with focal hypercellularity. They were composed of monomorphic spindle-stellate cells with a vague fascicular pattern. The nuclei were bland with only rare mitotic activity, and occasional multinucleation. The intervening stroma was typically abundant and ranged from myxoid to collagenous, with frequent rope-like collagen bundles. Three of the cases had a prominent vasculature ranging from numerous small curvilinear vessels to ectatic and branching staghorn-like vessels. Immunohistochemistry was negative for desmin, smooth muscle actin, S100, CD34, keratin, and epithelial membrane antigen. Each of the patients was treated by simple excision and none of the tumors were associated with local recurrence or metastasis. Based on their unique morphological and molecular attributes, we believe this represents a novel fibroblastic tumor for which we have tentatively proposed the name "PRRX-NCOAx-rearranged fibroblastic tumor."

[Diagnostic and predictive molecular pathology of head and neck neoplasms]

As a result of some seminal observations as well as a consequence of increasing use of modern and innovative molecular diagnostic technologies, a variety of new genetic aberrations have been discovered in head and neck neoplasms of different anatomic locations and histogenetic origins. These advances resulted in the establishment of new molecularly defined disease entities. On the other hand, some of these new genetic biomarkers paved the way to potentially promising novel therapeutic opportunities. Diverse old (well known in other entities) and newly discovered translocations and gene fusions represent the leading subgroup of these genetic aberrations. They have been detected not only in malignant epithelial neoplasms (carcinomas) of the salivary glands, but also in carcinomas from other head and neck sites as well as diverse mesenchymal tumors. In addition to these gene fusions, several activating mutations (such as CTNNB1 in sinonasal glomangiopericytoma) as well as inactivating mutations or deletions (like SMARCB1 loss in sinonasal carcinomas) were detected as new molecular markers. In the present review we summarize the relevant molecular alterations in topographically and histopathologically distinct tumors of the head and neck region with emphasis on recently established molecular markers.

Reassessing the Anatomic Origin of the Juvenile Nasopharyngeal Angiofibroma

OBJECTIVE

A modern imaging review is necessary to further define the anatomic origin of the juvenile nasopharyngeal angiofibroma.

METHODS

After institutional review board approval, a search from January 1998 to January 2013 yielded 33 male patients (aged 10-23 years) with pathologically proven juvenile nasopharyngeal angiofibroma lesions, as well as pretreatment computed tomography/magnetic resonance imaging. Juvenile nasopharyngeal angiofibroma involvement was assessed in the following regions: sphenopalatine foramen, pterygopalatine fossa, vidian canal, nasopharynx, nasal cavity, sphenoid sinus, choana, pterygomaxillary fissure/masticator space, orbit, and sphenoid bone.

RESULTS

The choana and nasopharynx were involved in all 33 patients. In contrast, only 22 lesions involved the pterygopalatine fossa, 24 lesions involved the sphenopalatine foramen, and 28 lesions involved the vidian canal.

CONCLUSIONS

Our results suggest that the juvenile nasopharyngeal angiofibroma origin is in the region of the choana and nasopharynx rather than the sphenopalatine foramen or pterygopalatine fossa.

Distinctive Patterns of CTNNB1 (β-Catenin) Alterations in Salivary Gland Basal Cell Adenoma and Basal Cell Adenocarcinoma

Salivary gland basaloid neoplasms are diagnostically challenging. Limited publications report that some basal cell adenomas harbor CTNNB1 mutations, and nuclear β-catenin expression is prevalent. We evaluated β-catenin expression in basal cell adenomas and adenocarcinomas in comparison with salivary tumors in the differential diagnosis and performed targeted genetic analysis on a subset of cases. β-catenin immunohistochemistry was performed on formalin-fixed, paraffin-embedded whole sections from 73 tumors. Nuclear staining was scored semiquantitatively by extent and intensity. DNA was extracted from 6 formalin-fixed, paraffin-embedded samples (5 basal cell adenomas, 1 basal cell adenocarcinoma) for next-generation sequencing. Nuclear β-catenin staining was present in 18/22 (82%) basal cell adenomas; most were diffuse and strong and predominant in the basal component. Two of 3 basal cell adenocarcinomas were positive (1 moderate focal; 1 moderate multifocal). All adenoid cystic carcinomas (0/20) and pleomorphic adenomas (0/20) were negative; 2/8 epithelial-myoepithelial carcinomas showed focal nuclear staining. Most β-catenin-negative tumors showed diffuse membranous staining in the absence of nuclear staining. Four of 5 basal cell adenomas had exon 3 CTNNB1 mutations, all c.104T>C (p.I35T). Basal cell adenocarcinoma showed a more complex genomic profile, with activating mutations in PIK3CA, biallelic inactivation of NFKBIA, focal CYLD deletion, and without CTNNB1 mutation despite focal β-catenin expression. Nuclear β-catenin expression has moderate sensitivity (82%) for basal cell adenoma but high specificity (96%) in comparison with its morphologic mimics. CTNNB1 mutation was confirmed in most basal cell adenomas tested, and findings in basal cell adenocarcinoma suggest possible tumorigenic mechanisms, including alterations in PI3K and NF-κB pathways and transcriptional regulation.

Variable expression of molecular markers in juvenile nasopharyngeal angiofibroma

Background:

Molecular categorisation may explain the wide variation in the clinical characteristics of juvenile nasopharyngeal angiofibroma.

Methods:

Variations in molecular markers in juvenile nasopharyngeal angiofibroma in an Indian population were investigated and compared with global reports.

Results:

Variable molecular marker expression was demonstrated at the regional and global levels. A wide variation in molecular characteristics is evident. Molecular data have been reported for only 11 countries, indicating a clear geographical bias. Only 58 markers have been studied, and most are yet to be validated.

Conclusion:

Research into the molecular epidemiology of juvenile nasopharyngeal angiofibroma is still in its infancy. Although the molecular variation is not well understood, data obtained so far have prompted important research questions. Hence, multicentre collaborative molecular studies are needed to establish the aetiopathogenesis and establish molecular surrogates for clinical characteristics.

A Comprehensive Review of Pediatric Tumors and Associated Cancer Predisposition Syndromes

An understanding of the role of inherited cancer predisposition syndromes in pediatric tumor diagnoses continues to develop as more information is learned through the application of genomic technology. Identifying patients and their relatives at an increased risk for developing cancer is an important step in the care of this patient population. The purpose of this review is to highlight various tumor types that arise in the pediatric population and the cancer predisposition syndromes associated with those tumors. The review serves as a guide for recognizing genes and conditions to consider when a pediatric cancer referral presents to the genetics clinic.

Distinctive Head and Neck Bone and Soft Tissue Neoplasms

Benign and malignant primary bone and soft tissue lesions of the head and neck are rare. The uncommon nature of these tumors, combined with the complex anatomy of the head and neck, pose diagnostic challenges to pathologists. This article describes the pertinent clinical, radiographic, and pathologic features of selected bone and soft tissue tumors involving the head and neck region, including angiofibroma, glomangiopericytoma, rhabdomyosarcoma, biphenotypic sinonasal sarcoma, chordoma, chondrosarcoma, and osteosarcoma. Emphasis is placed on key diagnostic pitfalls, differential diagnosis, and the importance of correlating clinical and radiographic information, particularly for tumors involving bone.

Update From The 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Nasopharynx

The current WHO classification system for tumors of the head and neck has made few changes from the previous edition with regards to tumors of the nasopharynx. The classification system is discussed here with particular attention to nasopharyngeal carcinoma, nasopharyngeal papillary adenocarcinoma, salivary gland anlage tumor, hairy polyp, juvenile angiofibroma, and other tumors.

Current status and clinical association of beta-catenin with juvenile nasopharyngeal angiofibroma

OBJECTIVE

A possible role of the APC/beta-catenin pathway in the pathogenesis of sporadic juvenile nasopharyngeal angiofibroma has been suggested. This paper presents its current status and clinical association in our patients.

METHOD

A prospective observational study was conducted at King George Medical University and Central Drug Research Institute, in Lucknow, India. Western blot analysis was undertaken in 16 cases to examine beta-catenin expression. The clinical details were recorded along with follow up observations, to determine associations.

RESULTS

Up-regulation of beta-catenin expression was seen in 69 per cent of cases. The clinical variables did not reveal significant differences between patients with extremes of expression (extreme under- vs over-expression). However, absent expression was shown exclusively in young adults aged over 18 years, while enhanced expression was associated with an altered facial profile.

CONCLUSION

Although a beta-catenin association was seen in a subset of our sporadic juvenile nasopharyngeal angiofibroma cases, its expression was not homogeneous. This is in contrast to the Western literature that suggests a universal (homogenous) enhanced expression in the majority. Hence, further research is required to better define its molecular cascade.

Loss of Reflex Tearing: An Expected Consequence of Juvenile Nasopharyngeal Angiofibroma

OBJECTIVE: To report the loss of reflex tearing after surgical treatment of juvenile nasopharyngeal angiofibroma (JNA).

STUDY DESIGN AND SETTING: A retrospective case series of 8 patients with surgical extirpation of JNA from 1995 to 2003 in a major teaching hospital setting was studied for symptomatic xerophthalmia.

RESULTS: One patient was lost to follow-up. Four of the remaining 7 patients reported a dry ipsilateral eye after surgical treatment of JNA.

CONCLUSION: The location of the pterygopalatine ganglion and its associated fibers in the pterygopalatine fossa is directly adjacent to the location of origin of JNA. Lacrimal innervation passes through the pterygopalatine ganglion. Given the extensive nature of advanced JNA and mandate for complete surgical excision, lacrimal dysfunction should be considered an expected consequence of surgery.

SIGNIFICANCE: The loss of reflex tearing has not been reported as a consequence of JNA or its surgical treatment. EBM Rating: C.

Glomangiopericytoma simulating an intracavernous meningioma

Background:

Glomangiopericytoma is an uncommonly encountered tumor of the nose and paranasal sinuses, accounting for <0.5% of all sinonasal tumors. Extension of these lesions to the anterior or middle cranial fossa is rare. When this occurs, diagnosing glomangiopericytoma is extremely challenging, as it is often confused with other anterior skull base tumors.

Case Description:

We report a case of a giant glomangiopericytoma localizing into the cavernous sinus in a 48-year-old female who presented with mild left-sided ptosis for 48 months. The lesion simulated an intracavernous meningioma on preoperative imaging. An expanded endoscopic endonasal approach was used to debulk the portion of the lesion in the medial compartment of the cavernous sinus. Postoperatively, the patient's ptosis resolved completely, and no new deficits were sustained.

Conclusion:

This is the only case of glomangiopericytoma localizing solely to the cavernous sinus reported to date.

CTNNB1 (β-Catenin)-altered Neoplasia: A Review Focusing on Soft Tissue Neoplasms and Parenchymal Lesions of Uncertain Histogenesis

β-catenin (CTNNB1) is a key regulatory molecule of the Wnt signaling pathway, which is important for tissue homeostasis and regulation of cell proliferation, differentiation, and function. Abnormal stabilization and nuclear accumulation of β-catenin as a consequence of missense mutations or alternative molecular mechanisms occurs at a high frequency in a variety of epithelial cancers. In mesenchymal neoplasia, the role of β-catenin has been traditionally considered limited to desmoid-type fibromatosis. However, the spectrum of β-catenin-driven (β-catenin-altered) neoplasia of mesenchymal origin has been steadily widening to include, in addition to desmoid tumors, a variety of benign and intermediate-biology neoplasms of soft tissue (intranodal palisaded myofibroblastoma), head and neck (juvenile nasopharyngeal angiofibroma and sinonasal hemangiopericytoma/glomangiopericytoma), and ovarian (microcystic stromal tumor) origin. In addition, several old and newly reported distinctive site-specific β-catenin-driven parenchymal neoplasms of uncertain histogenesis have been well characterized in recent studies, including solid-pseudopapillary neoplasm of the pancreas and its recently described ovarian counterpart, sclerosing hemangioma of lung and calcifying nested stromal-epithelial tumor of the liver. This review addresses the most relevant pathobiological and differential diagnostic aspects of β-catenin-altered neoplasms with emphasis on site-specific histologic and biological variations. In addition, the morphologic overlap and analogy as well as distinctness between these uncommon tumors will be presented and discussed. Furthermore, a note is made on association of some of these lesions with hereditary tumor syndromes, in particular with the familial adenomatous polyposis coli.

Identification of CTNNB1 mutations, CTNNB1 amplifications, and an Axin2 splice variant in juvenile angiofibromas

Juvenile angiofibromas (JAs) are benign fibro-vascular tumors occurring nearly exclusively in adolescent males. Even less is known about this rare tumor entity, alterations affecting the Wnt-pathway seem to play a pivotal role in tumor biology as activating CTNNB1 mutations have been detected. However, the knowledge of Wnt-pathway changes is still limited. Therefore, we aimed to determine in JAs further insight into Wnt/β-catenin pathway components. In our present study, genetic alterations of the Wnt-pathway members CTNNB1, APC, GSK3β, and Axin2 detected by metaphase comparative genomic hybridization (CGH) were shown to result in elevated transcript levels in the majority of JA samples compared to nasal mucosa stroma (p < 0.001, p = 0.001, p = 0.046, and p = 0.006, respectively). Additionally, amplifications of CTNNB1 were validated by fluorescence in situ hybridization (FISH) and genomic qPCR. Moreover, our mutation analysis detected already known mutations as well as, to the best of our knowledge, mutations and an interstitial deletion of CTNNB1 not described in JAs before. Additionally, a so far unknown transcribed Axin2 splice variant was found, but no further Axin2 mutations. Taken together, our current study supports the importance of aberrant Wnt-signaling as a common event in JAs, most likely by the observed genetic alterations driven by mutations, interstitial deletions but also amplifications of CTNNB1 contributing to the stabilization of β-catenin.

Soft tissue tumors of the sinonasal tract

Primary soft tissue tumors arising in the sinonasal tract are rare. While many mesenchymal neoplasms have been reported in the nasal cavity, sinuses, and nasopharynx, few are distinctive to this anatomic region. Some tumor types are relatively more common in this area, such as schwannoma and rhabdomyosarcoma. Nasopharyngeal angiofibroma and sinonasal hemangiopericytoma are unique entities of the sinonasal tract, as well as the recently characterized biphenotypic sinonasal sarcoma. This review discusses the clinical, morphologic, and immunohistochemical features and currently known molecular data of the more frequently encountered soft tissue tumors of the sinonasal tract.

Nuclear expression and gain-of-function β-catenin mutation in glomangiopericytoma (sinonasal-type hemangiopericytoma): insight into pathogenesis and a diagnostic marker

Glomangiopericytoma (sinonasal-type hemangiopericytoma) is a rare mesenchymal neoplasm with myoid phenotype (smooth muscle actin-positive), which distinguishes this tumor from soft tissue hemangiopericytoma/solitary fibrous tumor. Molecular genetic changes underlying the pathogenesis of glomangiopericytoma are not known. In this study, 13 well-characterized glomangiopericytomas were immunohistochemically evaluated for β-catenin expression. All analyzed tumors showed strong expression and nuclear accumulation of β-catenin. Following this observation, β-catenin glycogen serine kinase-3 beta phosphorylation region, encoded by exon 3, was PCR amplified in all cases and evaluated for mutations using Sanger sequencing. Heterozygous mutations were identified in 12 of 13 tumors. All mutations consisted of single-nucleotide substitutions: three in codon 32 (c.94G>C (n=2) and c.95A>T), four in codon 33 (two each c.98C>G and c.98C>T), two in codon 37 (c.109T>G), one in codon 41 (c.121A>G), and two in codon 45 (c.133T>C). At the protein level, these substitutions would lead to p.D32H, p.D32V, p.S33C, p.S33F, p.S37A, p.T41A, and p.S45L mutations, respectively. Previously, similar mutations have been reported in different types of cancers and shown to trigger activation of β-catenin signaling. All analyzed glomangiopericytomas showed prominent nuclear expression of cyclin D1, as previously shown for tumors with nuclear expression of β-catenin as a sign of oncogenic activation. These results demonstrate that mutational activation of β-catenin and associated cyclin D1 overexpression may be central events in the pathogenesis of glomangiopericytoma. In additon, nuclear accumulation of β-catenin is a diagnostic marker for glomangiopericytoma.

Recurrent mutations within the amino-terminal region of β-catenin are probable key molecular driver events in sinonasal hemangiopericytoma

Sinonasal hemangiopericytoma (SN-HPC) is an uncommon, site-specific, low-grade mesenchymal neoplasm of probable perivascular myoid cell origin. In contrast to solitary fibrous tumors of soft tissue and sinonasal tract origin, SN-HPCs were recently shown to lack recurrent NAB2-STAT6 fusion variants. Other molecular alterations known to occur in some of soft tissue perivascular myoid cell neoplasms were also absent in SN-HPC; thus, the molecular pathogenesis of SN-HPCs remained unknown. Guided by whole-genome sequencing combined with RNA sequencing of an index case, we analyzed a total of six SN-HPCs for mutations within the amino-terminal region of the gene CTNNB1 (cadherin-associated protein), β 1, 88 kDa, encoding β-catenin. All six cases showed missense mutations, with amino acid substitutions clustering at positions 33 to 45, corresponding to the recognition site of the β-catenin destruction complex. Similar CTNNB1 mutations have been described in a variety of epithelial and mesenchymal neoplasms. These mutations prevent β-catenin phosphorylation and proteasomal degradation but promote its nuclear accumulation and subsequent increased transcription of Wingless-related integration site target genes. Consistent with these molecular findings, β-catenin IHC showed consistent diffuse and strong nuclear staining of the tumor cells in all six SN-HPCs. Our results highlight, for the first time, CTNNB1 mutations as the likely initiating molecular events driving SN-HPC tumorigenesis, which places SN-HPC among the growing family of β-catenin-driven mesenchymal neoplasms.

Preliminary analysis of different microRNA expression levels in juvenile angiofibromas

Juvenile angiofibroma (JA) is a rare fibrovascular tumor affecting, almost exclusively, adolescent males. The finding of frequent β-catenin-mutations in JAs emphasized the significance of the Wnt-signaling pathway in tumor pathogenesis. In the last decade, microRNAs (miRNAs or miRs) have been found to be involved in cancer pathogenesis by post-transcriptional regulation of gene expression and have not been analyzed in JAs thus far. In the present study, the expression of 4 miRNAs (hsa-let-7d, hsa-miR-98, hsa-miR-125a-5p and hsa-miR-218) was analyzed in 13 JAs and 3 deepithelized inferior nasal turbinates that were used as control tissue. The miRNA expression of hsa-let-7d (P=0.158) and hsa-miR-98 (P=0.069) was not statistically different between the two tissue types, however, a significant decrease in expression was observed for hsa-miR-125a-5p (P=0.037) and hsa-miR-218 (P=0.009) in JAs compared to inferior nasal turbinates. As downregulation of miRNA 218 has been recently shown to result in stabilization and nuclear accumulation of β-catenin, the present data indicates further evidence for the importance of the Wnt-signaling pathway in JAs.

Expression of sex hormone receptors in juvenile angiofibromas and antiproliferative effects of receptor modulators

BACKGROUND

Predilection of juvenile angiofibromas in adolescent boys has prompted the hypothesis of hormone-dependent tumor growth. However, knowledge on expression and function of sex hormone receptors in juvenile angiofibromas is still sparse and inconsistent.

METHODS

Transcript and protein expression of sex hormone receptors in juvenile angiofibromas was studied by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and immunohistology/fluorescence. A bromodeoxyuridine assay was used to assess the antiproliferative effects of flutamide (androgen receptor antagonist) and tamoxifen (estrogen receptor modulator).

RESULTS

Significantly increased transcript levels were observed for androgen receptor, estrogen receptor α, follicle-stimulating hormone receptor, and luteinizing hormone receptor in juvenile angiofibromas versus the stroma of nasal mucosa. Estrogen receptor β and progesterone receptor mRNA levels were low and similar for both tissues. Estrogen receptor α protein was detected in juvenile angiofibroma tumors and mesenchymal cell lines. Flutamide and tamoxifen inhibited proliferation of cultured juvenile angiofibroma mesenchymal cells.

CONCLUSION

These findings contribute to the understanding of juvenile angiofibroma pathophysiology and offer novel therapeutic options.

Molecular pathogenesis of juvenile nasopharyngeal angiofibroma in brazilian patients

Juvenile nasopharyngeal angiofibroma (JNA) is a vascular tumor of the nasopharynx that accounts for 0.5% of all cancers of the head and neck. It primarily affects males aged 14-25 years. Of the many genes that mediate the development of JNA, GSTM1 has been most frequently associated with this vascular tumor. The loss of expression of GSTM1 (null genotype) is linked to the development of these tumors. The aim of this cross-sectional case study was to examine the prevalence of the GSTM1-null genotype in Brazilian patients with JNA. DNA was extracted from the leukocytes of blood samples from 10 patients. GSTM1 genotypes were analyzed using a PCR-based assay that was designed to identify the wild-type allele of GSTM1. All 10 patients (100%) were males, with a mean age of 17.8 years. The null genotype for GSTM1 was noted in 4 patients (40%)-1 (10%) at Fisch stage I, 1 (10%) at stage III, and 2 (20%) at stage II. No patient with this genotype had stage IV disease. There was no correlation between Fisch classification and GSTM1 genotype (P = .5695). The correlation between age at diagnosis and GSTM1 genotype was not significant (P = .728). The present findings indicate that there is evidence of an association between the GSTM1-null genotype and JNA in this studied Brazilian population.

Endoglin (CD105) expression on microvessel endothelial cells in juvenile nasopharyngeal angiofibroma: tissue microarray analysis and association with prognostic significance

BACKGROUND

The purpose of this study was to examine endoglin (CD105) expression on microvessel endothelial cells (ECs) in juvenile nasopharyngeal angiofibroma (JNA) and its relationship with recurrence.

METHODS

Immunohistochemistry was performed to detect CD105 expression in a tissue microarray from 70 patients with JNA. Correlation between CD105 expression on microvessel ECs and clinicopathological features, as well as tumor recurrence, were analyzed.

RESULTS

Immunohistochemistry revealed CD105 expression on ECs but not in stroma of patients with JNA. Chi-square analysis indicated CD105-based microvessel density (MVD) was correlated with JNA recurrence (p = .013). Univariate and multivariate analyses determined that MVD was a significant predictor of time to recurrence (p = .009). The CD105-based MVD was better for predicting disease recurrence (AUROC: 0.673; p = .036) than other clinicopathological features.

CONCLUSIONS

MVD is a useful predictor for poor prognosis of patients with JNA after curative resection. Angiogenesis, which may play an important role in the occurrence and development of JNA, is therefore a potential therapeutic target for JNA.

Systems-level analysis of clinically different phenotypes of juvenile nasopharyngeal angiofibromas

OBJECTIVES/HYPOTHESIS

To explore the molecular genetic background of juvenile nasopharyngeal angiofibromas and to identify biological processes and putative factors determining the different growth patterns of these tumors.

STUDY DESIGN

By comparing copy number and gene expression level changes of two clinically different phenotypes of juvenile nasopharyngeal angiofibromas, we aimed to find processes essential in the growth and development of these tumors. Based on the results and prior knowledge of the proteins significance for growth, we studied the expression of tyrosine kinase SYK in 27 tumor samples.

METHODS

Comparative genomic hybridization and gene expression analyses were performed for the two tumor samples, and protein expression of SYK was studied in 27 samples by immunohistochemical staining.

RESULTS

Between low- and high-stage juvenile nasopharyngeal angiofibromas, 1,245 genes showed at least a two-fold change in expression. The corresponding proteins of these transcripts were enriched in different biological processes. Protein kinase SYK was expressed in all 27 samples, and its intensity significantly correlated with tumor stage.

CONCLUSIONS

Because the molecular genetic background of juvenile nasopharyngeal angiofibroma is unknown, our aim was to investigate genomic alterations that could associate to low- and high-stage tumors. We were able to identify gene expression changes that relate to particular biological processes, but assessing clinically relevant molecular profiles still requires further characterization. Due to the low incidence of juvenile angiofibroma, in the future a combination of molecular profiling data from several studies would be useful in understanding the molecular background of the disease.

Fibroblastic and myofibroblastic tumors in children and adolescents

Fibroblastic and myofibroblastic tumors in children and adolescents are a relatively common group of soft tissue proliferations that range from reactive to hamartomatous to neoplastic, with a full spectrum of benign, intermediate, and malignant neoplasms. These lesions are diagnostically challenging because of morphologic and immunohistochemical overlap, despite significant clinical, genetic, and prognostic differences. The fibromatoses are a major subgroup, and all types of fibromatoses can occur in the 1st 2 decades of life. Intermediate and malignant fibroblastic-myofibroblastic tumors are an important group that includes variants of fibrosarcoma and other tumors with recurrent cytogenetic or molecular genetic abnormalities and low metastatic potential. Pathologic examination is enhanced by adjunct techniques, such as immunohistochemistry, cytogenetics, and molecular genetics, although morphology provides the ultimate criteria for a specific diagnosis. This article reviews the clinicopathologic features of fibroblastic and myofibroblastic tumors with an emphasis on the unique aspects of these neoplasms in children and adolescents, the use of diagnostic adjuncts, and differential diagnoses.

Identification of Familial Adenomatous Polyposis carriers among children with desmoid tumours

OBJECTIVE

Desmoid tumours are rare mesenchymal tumours with unpredictable progression and high recurrence risk. They can occur sporadically or in association with Familial Adenomatous Polyposis (FAP), which is caused by germline APC mutations. The Wnt/β-catenin pathway has a central role in the pathogenesis of desmoid tumours. These tumours can occur due to either a somatic CTNNB1 or APC mutation but can also be the first manifestation of FAP. Because germline APC analysis is not routinely performed in children with desmoid tumours, the diagnosis FAP may escape detection. The aim of this study is to form guidelines for the identification of possible APC germline mutation carriers among children with desmoid tumours, based on CTNNB1 mutation analysis and immunohistochemical analysis (IHC) for β-catenin.

PATIENTS AND METHODS

We performed IHC of β-catenin and mutation analysis of CTNNB1 and APC in 18 paediatric desmoid tumours, diagnosed between 1990 and 2009 in the Erasmus MC, Rotterdam.

RESULTS

In 11 tumours, IHC showed an abnormal nuclear β-catenin accumulation. In this group a CTNNB1 mutation was detected in seven tumours. In two tumours with an abnormal nuclear β-catenin accumulation and no CTNNB1 mutation, an APC mutation was identified, which appeared to be a germline mutation.

CONCLUSIONS

Aberrant staining of β-catenin in paediatric desmoids helps to identify children at risk for FAP. We recommend to screen paediatric desmoid tumours for nuclear localisation of β-catenin and consequently for CTNNB1 mutations. For patients with nuclear β-catenin expression and no CTNNB1 mutations, APC mutation analysis should be offered after genetic counselling.

Anti-proliferative effect of glucocorticoids on mesenchymal cells in juvenile angiofibromas

BACKGROUND

Glucocorticoids (GCs) not only regulate metabolic and inflammatory mechanisms, but also are known to suppress tumor growth. Despite previous detection of glucocorticoid receptors (GRs) in juvenile angiofibromas, their distribution and function have not further been studied.

METHODS

Juvenile angiofibroma tissue (n = 30), nasal mucosa specimens (n = 10), subepithelial stroma of nasal mucosa (n = 20), and primary fibroblasts from juvenile angiofibroma (n = 6) and nasal mucosa samples (n = 6) were analyzed by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence staining. The antiproliferative effect of GCs (dexamethasone, prednisolone, and hydrocortisone) in vitro was assessed using a bromdeoxyuridine (BrdU) assay.

RESULTS

An upregulation of GR transcripts and protein was shown in juvenile angiofibroma tissue and primary mesenchymal cells compared to nasal mucosa. Application of GCs resulted in a significantly higher antiproliferative effect on juvenile angiofibroma versus nasal mucosa fibroblasts in vitro.

CONCLUSION

Expression of GRs and antiproliferative effects of GCs on juvenile angiofibroma fibroblasts offer novel options for the treatment of this unique fibrovascular tumor.

Pediatric fibroblastic and myofibroblastic lesions

Fibrous lesions of infancy and childhood are a heterogeneous group of entities composed predominantly of fibroblasts and myofibroblasts, ranging from reactive lesions to neoplasms with a range of malignant potential. Although rare, their correct recognition by histopathology is important clinically as they exhibit a wide range of behaviors and may be associated with distinct underlying syndromes. Contributions from molecular diagnostics have enabled more accurate diagnosis, and have changed our concepts of some tumor types. In this review, we discuss the clinicopathologic spectrum of fibroblastic and myofibroblastic lesions of childhood and adolescence.

Stem cell-related proteins C-KIT, C-MYC and BMI-1 in juvenile nasopharyngeal angiofibroma--do they have a role?

Juvenile nasopharyngeal angiofibroma (JNA) is a highly vascular tumour, occurring almost exclusively in adolescent males. Histogenesis of JNA remains unclear, two optional theories proposing either fibrous or vascular tissue as the tissue of origin. Stem cell-related proteins have been discussed to possibly participate in the growth of these tumours. In our study, we reviewed retrospective clinicopathological data of 26 JNA patients. By immunohistochemistry, we investigated the cellular distribution and expression levels of stem cell-related proteins C-KIT, C-MYC and BMI-1 and their correlation with cell and vessel density of the tumour. Contrary to earlier reports, we detected C-KIT expression in addition to stromal cells also in endothelial cells. The C-KIT expression was more dominant in slit vessels than large vessels. A significant correlation was found between endothelial immunoexpression of C-KIT and cellular density of the tumour. C-MYC and BMI-1 expression was detected in stromal cells only. Due to our finding of C-KIT expression in both stromal and endothelial cells and the strong correlation between the endothelial C-KIT expression and cellular density, we suggest that, besides the stromal tissue, the vascular component might take part in the neoplastic growth of JNA.