Juvenile nasopharyngeal angiofibroma: an immunohistochemical characterisation of the stromal cell

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.

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.

Master Regulators of Epithelial-Mesenchymal Transition and WNT Signaling Pathways in Juvenile Nasopharyngeal Angiofibromas

Juvenile nasopharyngeal angiofibroma (JNA) is a rare fibrovascular benign tumor showing an invasive growth pattern and affecting mainly male adolescents. We investigated the role of epithelial–mesenchymal transition (EMT) and WNT signaling pathways in JNA. Gene expression profiles using nine JNA paired with four inferior nasal turbinate samples were interrogated using a customized 2.3K microarray platform containing genes mainly involved in EMT and WNT/PI3K pathways. The expression of selected genes (BCL2, CAV1, CD74, COL4A2, FZD7, ING1, LAMB1, and RAC2) and proteins (BCL2, CAV1, CD74, FZD7, RAF1, WNT5A, and WNT5B) was investigated by RT-qPCR (28 cases) and immunohistochemistry (40 cases), respectively. Among 104 differentially expressed genes, we found a significantly increased expression of COL4A2 and LAMB1 and a decreased expression of BCL2 and RAC2 by RT-qPCR. The immunohistochemistry analysis revealed a low expression of BCL2 and a negative to moderate expression of FZD7 in most samples, while increased CAV1 and RAF1 expression were detected. Moderate to strong CD74 protein expression was observed in endothelial and inflammatory cells. A significant number of JNAs (78%) presented reduced WNT5A and increased WNT5B expression. Overall, the transcript and protein profile indicated the involvement of EMT and WNT pathways in JNA. These candidates are promising druggable targets for treating JNA.

Angiofibroma of the Nasal Cavity in a Dog: Case Report

Nasopharyngeal angiofibroma is a histologic benign but locally aggressive vascular tumor described in humans. The description of this disease in dogs is limited. A mixed-breed female dog was presented with a history of epistaxis and nasal discharge. Rhinoscopy and computed tomography revealed a soft-tissue mass obstructing the entire nasal cavity, choana, maxillary recess, and right frontal sinus, but there was no bone or lymph node involvement. Histopathologic evaluation revealed irregular groups of blood vessels within a stroma of connective tissue, with secondary inflammation. Immunohistochemistry showed strong vimentin staining, mild factor VIII-related antigen staining, and negative staining for S100. The patient underwent tumor resection with fenestration surgery through the right maxillary bone, and there was tumor recurrence one year after surgery. This case report describes new findings regarding the immunohistochemical evaluation of nasopharyngeal angiofibroma in a dog. The laboratory and imaging findings, associated with a long-term follow-up, reinforce similar features between human and canine angiofibroma and may serve as a basis for immunohistochemical evaluation of this tumor in dogs.

β-catenin (CTNNB1) mutation and LEF1 expression in sinonasal glomangiopericytoma (sinonasal-type hemangiopericytoma)

Sinonasal glomangiopericytoma (SN-GPC) is an uncommon mesenchymal tumor with myoid differentiation. Recently, mutations in exon 3 of the gene coding for β-catenin (CTNNB1) and its nuclear expression were discovered in SN-GPC. β-catenin protein is a key regulatory molecule of the canonical Wnt signaling pathway. The expression of β-catenin target proteins is not well characterized in SN-GPC. We examined three SN-GPCs by immunohistochemistry and CTNNB1 mutation analysis. All cases expressed nuclear β-catenin. We identified CTNNB1 exon 3 mutations in two analyzable cases. Lymphoid enhancer-binding factor 1 (LEF1), a protein downstream from β-catenin, was also expressed in all cases. Our results further characterized the activation of the Wnt signaling pathway caused by CTNNB1 exon 3 mutation and suggest the utility of LEF1 immunohistochemistry in the differential diagnosis of SN-GPC.

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.

Nasopharyngeal Angiofibroma: A Clinical, Histopathological and Immunohistochemical Study of 42 Cases with Emphasis on Stromal Features

Nasopharyngeal angiofibroma is a benign but aggressive tumor of unknown etiology, typically occurring in adolescent males. It is described as a rare neoplasm; however, the prevalence seems to have geographic differences. All cases referred to our head and neck clinical and pathology service were reviewed. Most of the patients presented at an advanced stage. The clinical and radiographic features are presented and discussed. Histologically, the tumor shows a highly vascular fibrous proliferation with characteristic plump, angulated and stellate cells, categorized as fibroblasts. Immunohistochemistry was performed on 42 cases to further elucidate the nature of these cells. The stromal cells expressed vimentin and factor XIIIa, the latter expressed most commonly in the giant stellate cells. Inflammation was almost exclusively present in peripheral subepithelial areas. Mast cells were abundant, even in the absence of other inflammatory cells. Lymphatics were observed principally in peripheral regions. Proliferating cells (Ki-67 reactive) were restricted to endothelial cells.

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.

Hormonal receptors and vascular endothelial growth factor in juvenile nasopharyngeal angiofibroma: immunohistochemical and tissue microarray analysis

CONCLUSION

This work demonstrated that juvenile nasopharyngeal angiofibromas (JNAs) express high levels of hormone receptors and vascular endothelial growth factor (VEGF) compared with normal nasal mucosa. The interaction between hormone receptors and VEGF may be involved in the initiation and growth of JNA.

OBJECTIVES

JNA is a rare benign tumor that occurs almost exclusively in male adolescents. Although generally regarded as a hormone-dependent tumor, this has not been proven in previous studies. The aim of this study was to investigate the role of hormone receptors in JNA and the relationship with clinical characteristics.

METHODS

Standard immunohistochemical microarray analysis was performed on 70 JNA samples and 10 turbinate tissue samples. Specific antibodies for androgen receptor (AR), estrogen receptor-α (ER-α), estrogen receptor-β (ER-β), progesterone receptor (PR), and VEGF were examined, and the relationships of receptor expression with age, tumor stage, and bleeding were evaluated.

RESULTS

RESULTS showed that JNA expressed ER-α (92.9%), ER-β (91.4%), AR (65.7%), PR (12.8%), and VEGF (95.7%) at different levels. High level of VEGF was linked to elevated ER-α and ER-β. There was no significant relationship between hormonal receptors and age at diagnosis, tumor stage or bleeding. However, overexpression of ER-α was found to be an indicator of poor prognosis (p = 0.031).

p40 is a more specific marker than p63 for cutaneous poorly differentiated squamous cell carcinoma

BACKGROUND

Poorly differentiated squamous cell carcinoma (SCC) of the skin may pose a diagnostic challenge for pathologists. p40 is a recently introduced antibody that recognizes specific p63 protein isoforms and has shown superior results labeling non-cutaneous SCC. We hypothesize that p40 may improve diagnostic accuracy of poorly differentiated SCC.

METHODS

Twelve cases of poorly differentiated SCC were stained with p63, p40 and cytokeratin MNF116. Control cases included nine atypical fibroxanthoma (AFX), five cutaneous leiomyosarcoma (LMS) and three giant cell tumors of soft tissue (GCTST).

RESULTS

All 12 cases labeled with p63 and p40 and 11/12 were positive with MNF116. Whereas p40 labeled fewer cells, it showed exclusive nuclear staining, with no staining of cytoplasm or of background cells, in contrast to p63. Six of nine AFX and 2 of 3 GCTST showed scattered nuclear staining with p63 but were negative with p40. Additionally, one LMS showed focal staining with MNF116 but was negative with p40.

CONCLUSION

For the diagnosis of cutaneous poorly differentiated SCC, p40 appears equally sensitive to MNF116 and p63. While labeling fewer cells, p40 labels without confounding staining of tumor cytoplasm or background cells. More importantly, p40 appears to be more specific for SCC than p63 and MNF116, each of which occasionally labels non-squamous tumors.

Nasal septal angiofibroma, a subclass of extranasopharyngeal angiofibroma

OBJECTIVE

Extranasopharyngeal angiofibromas (ENA) arising from the nasal septum or nasal septal angiofibromas are extremely rare; only 13 such cases have been reported in the international literature. Our objective is to describe the presentation, workup, and surgical management of these lesions.

STUDY DESIGN

Case reports were done.

SETTING

The setting was a tertiary care referral center and the Veterans Affairs Medical Center. PATIENTS, INTERVENTIONS, AND RESULTS: We present 2 cases of extranasopharyngeal angiofibroma occurring on the nasal septum.

CONCLUSIONS

In this report, we discuss the occurrence, the histopathologic findings, and the treatment of nasal septal angiofibroma.

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.

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.

Craniofacial approaches to large juvenile angiofibromas

OBJECT

Craniofacial approaches provide excellent exposure to lesions in the anterior and middle cranial fossae. The authors review their experience with craniofacial approaches for resection of large juvenile nasopharyngeal angiofibromas.

METHODS

Between 1992 and 2009, 22 patients (all male, mean age 15 years, range 9-27 years) underwent 30 procedures. These cases were reviewed retrospectively.

RESULTS

Gross-total resection of 17 (77%) of the 22 lesions was achieved. The average duration of hospitalization was 8.2 days (range 3-20 days). The rate of recurrence and/or progression was 4 (18%) of 22, with recurrences occurring a mean of 21 months after the first resection. All patients underwent preoperative embolization. Nine patients (41%) developed complications, the most common of which was CSF leakage (23%). The average follow-up was 27.7 months (range 2-144 months). The surgery-related mortality rate was 0%. Based on their mean preoperative (90) and postoperative (90) Karnofsky Performance Scale scores, 100% of patients improved or remained the same.

CONCLUSIONS

The authors' experience shows that craniofacial approaches provide an excellent avenue for the resection of large juvenile nasopharyngeal angiofibromas, with acceptable rates of morbidity and no deaths.

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.

Markers of vascular differentiation, proliferation and tissue remodeling in juvenile nasopharyngeal angiofibromas

Juvenile nasopharingeal angiofibroma (JNA) is a histologically benign locally aggressive tumor characterized by irregular vessels embedded in a fibrous stroma. Excessive vascularity results in bleeding complications, and the inhibition of angiogenesis is a promising strategy for managing extensive JNA tumors. To better characterize the endothelial components of JNA, we aimed to evaluate markers of vascular differentiation and proliferation, such as friend leukemia integration-1 (FLI-1) and endoglin, lymphatic markers, including podoplanin and vascular endothelial growth factor receptor 3 (VEGFR3) and its cognate ligand VEGFC, GLUT-1, a diagnostic marker that discriminates between hemangiomas and vascular malformations, and two markers of tissue remodeling, stromelysin 3 (ST3) and secreted acid protein rich in cysteine (SPARC). Antigens were assessed immunohistochemically in vessels and stromal cells of JNA archival cases (n=22). JNA endothelial cells were positive for endoglin, VEGFC and FLI-1, whereas podoplanin and VEGFR3 were negative in all cases. Both endothelial cells and fibroblasts stained for ST3 and SPARC. GLUT-1 was investigated in JNA cases, in infantile hemangiomas (n=123) and in vascular malformations (n=135) as controls. JNAs and vascular malformations were GLUT-1-negative, while hemangiomas showed positive staining. The presence of markers of endothelial differentiation and proliferation highlighted the hyper-proliferative state of JNA vessels. The absence of podoplanin and VEGFR3 underscores their blood endothelial cell characteristic. The absence of GLUT-1 discriminates JNAs from hemangiomas. ST3 and SPARC up-regulation in endothelial cells and fibroblasts may contribute to a compensatory signaling for controlling angiogenesis. Some of these markers may eventually serve as therapeutic targets. Our results may aid in the understanding of JNA pathophysiology.

Transient visual loss and isolated disk edema in juvenile nasopharyngeal angiofibroma

Juvenile nasopharyngeal angiofibroma is a well-described but rare benign tumor that mainly affects adolescent boys. Although it is capable of extravagant local extension and tissue destruction, the tumor is amenable to effective therapy. Ocular or visual complications have been little noted in the literature. We report a case whose sole symptom was unilateral transient visual impairment and findings were limited to a nonspecific optic disk edema.