Neuroendocrine neoplasms of the sinonasal region

Personalized Approach to Olfactory Neuroblastoma Care

Olfactory neuroblastoma (ONB) is an uncommon neuroendocrine malignancy arising from the olfactory neuroepithelium. ONB frequently presents with nonspecific sinonasal complaints, including nasal obstruction and epistaxis, and diagnosis can be obtained through a combination of physical examination, nasal endoscopy, and computed tomography and magnetic resonance imaging. Endoscopic resection with negative margins, with or without craniotomy, as necessary, is the standard of care for definitive treatment of ONB. Regional metastasis to the neck is often detected at presentation or may occur in a delayed fashion and should be addressed through elective neck dissection or radiation. Adjuvant radiotherapy should be considered, particularly in the case of high grade or tumor stage, as well as positive surgical margins. Systemic therapy is an area of active investigation in both the neoadjuvant and adjuvant setting, with many advocating in favor of induction chemotherapy for significant orbital or intracranial involvement prior to surgical resection. Various targeted immunotherapies are currently being studied for the treatment of recurrent or metastatic ONB. Prolonged locoregional and distant surveillance are indicated following definitive treatment, given the tendency for delayed recurrence and metastasis.

Functional Olfactory Neuroblastoma Inducing Symptomatic SIADH

Olfactory neuroblastoma (ONB) is a rare malignancy of the sinonasal cavity, originating from neuroepithelial olfactory cells. Olfactory neuroblastoma can be difficult to diagnose due to its anatomic position and variable symptomatic presentation, leading to diagnosis at a more advanced stage. Here, we present the case of a 35-year-old man with no previous medical history who had a bicycle accident secondary to syncope. He was found to be hyponatremic and suspected to have syndrome of inappropriate antidiuretic hormone secretion (SIADH). In the workup of SIADH, a brain magnetic resonance imaging revealed a mass in the left middle meatus. The lesion secreted inappropriate amounts of ADH, resulting in symptomatic paraneoplastic SIADH. This ultimately led to the early recognition and successful resection of this rare ONB. The patient has remained disease-free for over 5 years. This case is a fortunate example of a functional malignancy of the sinonasal tract that was discovered early and successfully treated as a result of symptomatic SIADH.

Syndrome of Inappropriate Antidiuretic Hormone Release Secondary to Ectopic Olfactory Neuroblastoma: Case Report and Review of Literature

Ectopic olfactory neuroblastoma (ONB) is a rare neuroendocrine sinonasal malignancy which arises from sinonasal regions where olfactory neuroepithelium does not exist. Presentation of syndrome of inappropriate antidiuretic hormone release (SIADH) in patients with ectopic ONB is extremely rare. We report a case of a 22-year-old patient with ectopic ONB and paraneoplastic SIADH that was managed at our center. The ONB was arising from the left lamina papyracea and extending into the maxillary and ethmoid sinuses and filling the nasal cavity. Correction of sodium levels occurred within 24 hours of endoscopic resection via a combined trans-nasal transorbital approach. To avoid negative sequela secondary to rapid sodium correction, the patient was managed by desmopressin to obtain gradual sodium correction, which was achieved on the fourth postoperative day. Ectopic presentation of ONB with paraneoplastic SIADH is extremely rare with only 7 cases reported in the literature to date. Management via surgical resection and/or radiotherapy for these patients requires the managing clinician to be vigilant of serum sodium levels. A multidisciplinary approach is essential for optimal outcomes.

Proceedings of the 2023 North American Society of Head and Neck Pathology Companion Meeting, New Orleans, LA, March 12, 2023: Navigating New Developments in High Grade Sinonasal Neuroendocrine and Neuroectodermal Neoplasms

Although the definitions of sinonasal neuroendocrine and neuroectodermal neoplasms did not change substantially in the 5th edition WHO Classification of Head and Neck Tumours, the diagnosis of olfactory neuroblastoma (ONB), small cell neuroendocrine carcinoma, and large cell neuroendocrine carcinoma remains quite challenging in practice. Ambiguities surrounding the amount of keratin expression allowable in ONB and the amount of neuroendocrine differentiation seen in sinonasal undifferentiated carcinoma (SNUC) lead to significant diagnostic discrepancies at the high grade end of this tumor spectrum. Furthermore, a group of problematic neuroepithelial tumors that show overlapping features of ONB and neuroendocrine carcinoma have never been recognized in formal classification schemes. Since publication of the 5th edition WHO, two new tumor entities have been proposed that help resolve these problems. Olfactory carcinoma is defined by high grade keratin-positive neuroectodermal cells with frequent intermixed glands and shows recurrent Wnt pathway, ARID1A, and RUNX1 alterations. IDH2-mutant sinonasal carcinoma is a molecularly-defined category that encompasses tumors with undifferentiated (SNUC), large cell neuroendocrine, and neuroepithelial phenotypes. This review will provide a practical overview of these emerging entities and their application to diagnostic challenges in the post-WHO sinonasal neuroendocrine and neuroectodermal tumor classification.

The contemporary management of cancers of the sinonasal tract in adults

Sinonasal malignancies make up <5% of all head and neck neoplasms, with an incidence of 0.5-1.0 per 100,000. The outcome of these rare malignancies has been poor, whereas significant progress has been made in the management of other cancers. The objective of the current review was to describe the incidence, causes, presentation, diagnosis, treatment, and recent developments of malignancies of the sinonasal tract. The diagnoses covered in this review included sinonasal undifferentiated carcinoma, sinonasal adenocarcinoma, sinonasal squamous cell carcinoma, and esthesioneuroblastoma, which are exclusive to the sinonasal tract. In addition, the authors covered malignances that are likely to be encountered in the sinonasal tract-primary mucosal melanoma, NUT (nuclear protein of the testis) carcinoma, and extranodal natural killer cell/T-cell lymphoma. For the purpose of keeping this review as concise and focused as possible, sarcomas and malignancies that can be classified as salivary gland neoplasms were excluded.

Optimal Combination of Neuroendocrine Markers for the Detection of High-Grade Neuroendocrine Tumors of the Sinonasal Tract and Lung

PURPOSE OF REVIEW

Identification of neuroendocrine (NE) differentiation is critical to the classification of head and neck (HN) and lung tumors. In combination with tumor morphology, immunohistochemical (IHC) documentation of NE differentiation is necessary for the diagnosis of NE tumors. The purpose of this study is to determine the sensitivity and concordance of two novel NE markers (mASH1, INSM1) across a group of high-grade NE tumors of the sinonasal tract and lung, and to compare their expression with the current widespread use of conventional NE markers, synaptophysin (SYN) and chromogranin A (CGA). In addition, expression of PARP1 is examined as a potential novel therapeutic target.

RECENT FINDINGS

Thirty-nine high-grade NE tumors, 23 of the HN and 16 of the lung, were reevaluated by two subspecialized HN and thoracic pathologists, and subsequently stained with mASH1, INSM1, and PARP1. Sensitivity and degree of concordance of all possible combinations of markers were assessed. Sensitivities (standard error) were as follows: mASH1 41% (0.08), INSM1 44% (0.08), SYN 56% (0.08), and CGA 42% (0.09); combination of all four NE markers: 73% (0.08). Sensitivity and standard error for PARP1 was 90% and 0.05, respectively. Highest sensitivity to detect NE differentiation in high-grade NE tumors of the HN and thoracic region was achieved with a combination of four NE markers. Moderate concordance was found with combinations of mASH1 and INSM1 and traditional NE markers, respectively. Consistent overexpression of PARP1 in high-grade tumors with NE differentiation in the HN and lung opens eligibility for PARP1 inhibitor trials.

Nasopharyngeal Large Cell Neuroendocrine Carcinoma Synchronized With Nasopharyngeal Squamous Cell Carcinoma: A Case Report and Review of Literature

Neuroendocrine carcinomas (NECs) are poorly differentiated neuroendocrine tumors of the upper respiratory tract. We present an extremely rare case of nasopharyngeal large cell neuroendocrine carcinoma (LCNEC) synchronized with nasopharyngeal squamous cell carcinoma (SCC). Both SCC and LCNEC are associated with Epstein-Barr virus (EBV) infection, supported by the positive result of Epstein-Barr encoding region in-situ hybridization. Strong correlation is found between EBV infection and nasopharyngeal malignancies. Furthermore, the EBV status might be a crucial prognostic factor in nasopharyngeal LCNEC. EBV-positive LCNEC is effective to chemoradiotherapy, and may have preferable outcome than EBV-negative LCNEC arising in the nasopharynx or other sites. The recognition of the EBV status is important for patients to receive appropriate treatment.

Biomarkers for Immunotherapy in Poorly Differentiated Sinonasal Tumors

The sinonasal cavities harbor a wide variety of rare cancer types. Histopathological classification can be challenging, especially for poorly differentiated tumors. Despite advances in surgery and radio-chemotherapy, the 5-year survival rate is still very low. Thus, there is an unmet clinical need for new therapeutic options. We retrospectively evaluated poorly differentiated tumors of 9 different histological subtypes from 69 patients who had received conventional treatments for the presence of CD8+ tumor-infiltrating lymphocytes (TILs), as well as the expression of PD-L1 and microsatellite instability (MSI) markers MLH1, MSH2, MSH6 and PMS2, as biomarkers for immunotherapy. CD8+ TILs were present in 23/69 (33%) cases, PD-L1 expression was observed in 23/69 (33%), and markers for MSI positivity in 5/69 (7%) cases. CD8+ TILs correlated with PD-L1 positivity, while both were mutually exclusive with MSI markers. None of the biomarkers were associated with clinical features as age, gender or tumor stage. Cases with CD8+ TILs and PD-L1 positivity showed a tendency toward worse disease-specific survival. Immune checkpoint inhibitors are emerging as new options for treatment of many tumor types. Our results indicate that also a substantial subset of patients with poorly differentiated sinonasal tumors may be a candidate to be treated with this promising new therapy.

Expressions of NeuroD and GAP43 as diagnostic markers for olfactory neuroblastoma

OBJECTIVE

Olfactory neuroblastoma (ONB) is often difficult to pathologically distinguish from other small round cell tumors (SRCTs) arising in the nasal cavities. Although there are several diagnostic markers used for differential diagnosis of ONB, these molecules are also expressed in various neuronal derived tumors. Here, we examined the expression of NeuroD, GAP43, and olfactory marker protein (OMP) in ONB and non-ONB SRCT to determine their utility in the differential diagnosis of ONB.

METHODS

Twenty-six patients diagnosed with and treated for ONB at Kobe University Hospital between 1997 and 2017 with formalin-fixed, paraffin-embedded biopsy or surgical resection specimens were included. The expressions of NeuroD, GAP43, and OMP were immunohistochemically examined in these 26 ONB specimens and specimens from 13 SRCTs arising in the nasal cavities for reference.

RESULTS

Among the 26 ONB samples, focal, patchy, and marked staining for NeuroD was observed in 4, 3, and 9 samples, respectively. Focal, patchy, and marked GAP43 staining was observed in 5, 3, and 11 samples, respectively. Consequently, marked positive staining for either NeuroD or GAP43 was observed in 54% (14/26) of ONBs. Among the 13 SRCTs, marked staining for NeuroD was observed in two small cell carcinomas, one undifferentiated carcinoma, and one neuroendocrine carcinoma, whereas marked positive staining for GAP43 was observed only in one undifferentiated carcinoma. No specimen in this study exhibited OMP staining.

CONCLUSIONS

Our results suggest possible roles of GAP43 immunostaining in the differential diagnosis of ONB.

Sinonasal Tumors With Neuroepithelial Differentiation (Olfactory Carcinoma): Delineation of Their Pathologic and Clinical Features With Insights into Their Relationship to Olfactory Neuroblastoma and Sinonasal Carcinoma

Olfactory carcinoma is one of many names applied to sinonasal malignancies with histologic similarity to olfactory neuroblastoma (ONB) but cytokeratin expression or gland formation. It is unclear whether these neuroepithelial tumors represent a unified category and if they are separate from ONB and currently-recognized sinonasal carcinomas. This study aims to explore their clinicopathologic characteristics based on a large collective experience. A total of 53 sinonasal tumors with neuroepithelial differentiation were identified affecting 41 men and 12 women, median age 47 years (range: 12 to 82 y). The vast majority arose in the superior nasal cavity and presented at the high Kadish-Morita stage. Frequent histologic findings included (1) lobulated and solid growth, (2) rosettes and/or neurofibrillary stroma, (3) high-grade cytology, (4) complex, often ciliated glands, (5) nonfocal pancytokeratin expression, (6) neuroendocrine pos+itivity, and (7) variable S100-positive sustentacular cells. Twelve patients with available follow-up (48%) developed progressive disease at a median 8 months (range: 0 to 114 mo to progression), and 7 (28%) died of disease. Despite disparate historical terminology, neuroepithelial differentiation is a recurrent and recognizable histologic pattern that is associated with aggressive behavior in sinonasal tumors. While tumors with this phenotype may originate from olfactory mucosa, well-developed epithelial features warrant separation from conventional ONB and neural elements distinguish them from most sinonasal carcinomas. Although their full histogenesis remains uncertain and some heterogeneity may exist, we propose that this pattern is sufficiently distinctive to merit separate recognition as olfactory carcinoma. Use of consistent nomenclature may facilitate greater recognition of tumors with this phenotype and understanding of their pathogenesis and classification.

The prognostic value of S-100 protein and Ki-67 index in olfactory neuroblastoma

OBJECTIVE

To evaluate the prognostic value of S-100 protein and Ki-67 labeling index in olfactory neuroblastomas.

METHODS

A retrospective study was conducted on a cohort of 85 patients with olfactory neuroblastomas. The immunohistochemical expression of S-100 and Ki-67 was assessed, and the predictive value of S-100 and Ki-67 was further evaluated. The optimal cutoff value of Ki-67 labeling index was determined using time-dependent receiver operating characteristic curve analysis. Overall survival and progression-free survival were assessed using the Kaplan-Meier method.

RESULTS

A cut-off Ki-67 labeling index value of 67.5% was determined for prognosis in patients with olfactory neuroblastomas. There was a significant correlation between Ki-67 expression and cervical lymph node metastasis (P = 0.049). Compared with S-100 (+), S-100 (-) was associated with a higher rate of lymph node metastasis and a higher level of Ki-67 (P = 0.007, < 0.001, respectively), as well as an advanced Kadish stage (P = 0.037). Survival analyses showed that patients with S-100 (+) had better 5-year overall survival than those with S-100 (-) (P = 0.028), and patients with both S-100 (+) and Ki-67 (<67.5%) had superior 5-year overall survival compared with all the other patients (P = 0.0225).

CONCLUSION

Our findings suggest that S-100 combined with Ki-67 labeling index are reliable prognostic factors in patients with olfactory neuroblastomas.

Sinonasal Neuroendocrine Carcinoma: 15 Years of Experience at a Single Institution

Objectives  Sinonasal neuroendocrine carcinomas (SNECs) are among the rarest paranasal sinus cancers. Consensus guidelines for therapy are difficult to develop due to limited data regarding the natural history and successful treatment of these tumors. This study presents 15 years of experience treating SNEC at a single institution and a review of the literature. Design  Retrospective review. Setting  Academic medical center in the United States. Participants  Patients diagnosed with primary SNEC. Main Outcome Measures  Overall survival. Results  Thirteen patients were identified and included. Overall estimated survival was 74.6% at 5 years. Ten of 13 (76.9%) patients were diagnosed with high-grade neuroendocrine carcinoma and three (23.1%) with intermediate or low grade. All three patients with low- or intermediate-grade cancer survived more than 10 years from their initial diagnosis (median survival: 11.6 years) and are currently alive. The four patients who died had high-grade carcinoma, and estimated overall 5-year survival for all patients with high-grade carcinomas was 65.6%. Five patients, all with high-grade carcinoma, of seven who completed primary chemoradiation therapy (CRT) required salvage resection, and 60% are alive without disease. Conclusion  This cohort has a higher overall rate of survival than many recent case series and reviews. There is consensus that multimodal therapy is preferred over monotherapy, but approaches to treatment vary widely. Our approach of surgical resection as primary therapy for low-grade tumors and primary CRT for high-grade SNEC has been successful, and could indicate hope for improved survival among these patients.

Methylation Drivers and Prognostic Implications in Sinonasal Poorly Differentiated Carcinomas

Simple Summary

Poorly differentiated sinonasal carcinomas (PDSNCs) are rare neoplasms that include a wide spectrum of malignancies characterized by alteration in different epigenetic mechanisms (SWI/SNF complex, IDH2, NUT). The aim of our study was to verify if the identification of specific genetic and epigenetic alterations can be useful to recognize different clinico-pathological subsets of PDSNCs to guide treatment decisions. In our cohort, 14 cases showed alterations in SWI/SNF complex or IDH2 genes, which were associated with a higher global DNA methylation level and worst prognosis. The integration of genetic and epigenetic features appears to be a good strategy to improve the clinico-pathological classification of these tumors and to recognize distinct prognostic entities that deserve tailored clinical management.

Abstract

Background: Poorly differentiated sinonasal carcinomas (PDSNCs) are rare and aggressive malignancies, which include squamous cell carcinoma (SCC), sinonasal undifferentiated carcinoma (SNUC), and neuroendocrine carcinomas (NEC). Several epigenetic markers have been suggested to support the histopathological classification, predict prognosis, and guide therapeutic decision. Indeed, molecularly distinct subtypes of sinonasal carcinomas, including SMARCB1-INI1 or SMARCA4 deficient sinonasal carcinoma, isocitrate dehydrogenase (IDH)-mutant SNUC, ARID1A mutant PDSNCs, and NUT carcinomas, have recently been proposed as separate entities. Identification of aberrant DNA methylation levels associated with these specific epigenetic driver genes could be useful for prognostic and therapeutic purpose. Methods: Histopathological review and immunohistochemical study was performed on 53 PDSNCs. Molecular analysis included mutational profile by NGS, Sanger sequencing, and MLPA analyses, and global DNA methylation profile using LINE-1 bisulfite-PCR and pyrosequencing analysis. Results: Nine SWI/SNF complex defective cases and five IDH2 p.Arg172x cases were identified. A significant correlation between INI-1 or IDH2 defects and LINE-1 hypermethylation was observed (p = 0.002 and p = 0.032, respectively), which were associated with a worse prognosis (p = 0.007). Conclusions: Genetic and epigenetic characterization of PDSNCs should be performed to identify distinct prognostic entities, which deserved a tailored clinical treatment.

MRI of Sinonasal Malignancies

ABSTRACT

Sinonasal cavity is an important subsite in head and neck tumors. There are a myriad of malignancies that present within this area. Adequate staging for treatment planning requires multimodality evaluation. Magnetic resonance imaging (MRI) forms an important component in the evaluation of sinonasal tumors. We sought to review the most common sinonasal tumors, including sinonasal anatomy, clinical features, and common imaging features. A literature review was performed to evaluate common sinonasal tumors. Owing to the different tissue types within the sinonasal cavity, there are multiple different tumor pathologies within the sinonasal compartment. Most present in adults although some present in the young. Many of these tumor types have imaging overlaps, although some have a characteristic appearance. MRI can aid in soft tissue delineation, evaluation of multicompartmental extension, intracranial spread, and perineural spread. Sinonasal tumors are a heterogeneous group for which soft tissue delineation via MRI forms an important role in ensuring adequate treatment planning to improve outcomes, decreasing morbidity, and improve functional outcomes.

High-grade sinonasal carcinomas and surveillance of differential expression in immune related transcriptome

The skull base is the location of a wide variety of malignant tumors. Among them is sinonasal undifferentiated carcinoma (SNUC), a highly aggressive sinonasal neoplasm that was recently reclassified into subgroups of high-grade carcinomas with unique genomic events (e.g., SMARC-deficient carcinoma, nuclear protein in testis NUT carcinoma). Other high-grade carcinomas in this location are neuroendocrine carcinomas, sinonasal adenocarcinomas, and teratocarcinosarcomas. Given the rarity of these tumors, little transcriptomic data is available. The aim of this study was to characterize the immune-oncology gene expression profile in SNUC and other high-grade sinonasal carcinomas. Next-generation sequencing was performed in 30 high-grade sinonasal carcinoma samples using the HTG EdgeSeq Precision Immuno-Oncology Panel. Ingenuity pathway analysis was performed to understand the immunobiology, signaling, and functional perturbations during tumor development. The samples were divided into 3 groups: 21 SNUCs and SMARC-deficient sinonasal carcinomas; 5 high-grade neuroendocrine carcinomas (HGNECs), with small cell and large cell variants; and 4 high-grade sinonasal carcinomas (HGSNCs) of mixed histology (1 NUT carcinoma, 1 teratocarcinosarcoma, and 2 sinonasal adenocarcinomas). PRAME and ASCL1 emerged as upregulated transcripts with strong protein validation for SNUC and HGNEC; other upregulated candidates EZH2 and BRCA1 offer consideration for alternative targeted therapy, and downregulation of major histocompatibility complex molecules and chemokines represent another hurdle in the development of effective immunotherapy. This immune-oncology gene expression analysis of 3 groups of high-grade sinonasal carcinoma with emphasis on SNUC identified a number of differentially expressed transcripts reflecting effects on tumorigenesis. Identification of immune pathways should be further investigated for possible integration of immunotherapy into a multidisciplinary approach to these cancers and personalized treatment.

IDH2 Mutation Analysis in Undifferentiated and Poorly Differentiated Sinonasal Carcinomas for Diagnosis and Clinical Management

A large number of tumor types arise from the mucosa of the sinonasal cavities. Although presenting clinically distinct behavior, due to poorly differentiated histologic features, they can be difficult to classify correctly. Our aim was to investigate whether IDH2 and IDH1 mutations may be specific to a subset of undifferentiated and poorly differentiated sinonasal carcinomas. A total of 125 tumor samples of 7 different histologic subtypes were analyzed for IDH mutations by sequencing and mutant-specific immunohistochemistry, and the results were correlated to clinical and follow-up data. The highest incidence of IDH2 mutations occurred in sinonasal undifferentiated carcinoma, with 11/36 (31%) cases affected. However, also, 1/9 neuroendocrine carcinomas, 2/4 high-grade non-intestinal-type adenocarcinomas, and 1/8 poorly differentiated squamous cell carcinomas carried the IDH2 mutation, whereas 1/48 intestinal-type adenocarcinomas harbored an IDH1 mutation. Immunohistochemical analysis of mutant IDH1/2 produced a number of false-negative results, but also 1 false-positive tumor was found. Disease-specific survival was more favorable in IDH2-mutant versus wild-type cases. Our data suggest that IDH-mutant sinonasal cancers, independent of their histologic subtype, may represent a distinct tumor entity with less aggressive clinical behavior. Clinically, patients with these mutations may benefit from specific IDH-guided therapies.

Management of olfactory neuroblastoma, neuroendocrine carcinoma, and sinonasal undifferentiated carcinoma involving the skullbase

INTRODUCTION

Sinonasal tumors that harbor neuroendocrine histologic features include olfactory neuroblastoma (previously known as esthesioneuroblastoma), sinonasal neuroendocrine carcinoma, and sinonasal undifferentiated carcinoma. These tumors represent a diverse spectrum of clinical behavior and as such require histology-specific management. Herein, we review the management of these sinonasal tumors with neuroendocrine features and discuss fundamentals of multi-modality care for each histology. An emphasis is placed on olfactory neuroblastomas, given their relative frequency and skullbase origin.

METHODS

A comprehensive literature review on contemporary management of olfactory neuroblastoma, sinonasal neuroendocrine carcinoma, and sinonasal undifferentiated carcinoma was performed.

RESULTS

Management of sinonasal tumors with neuroendocrine features can include surgical resection, radiation therapy, and/or chemotherapy. Due to their site of origin, these tumors can frequently involve the skullbase, which can require site-specific care. The optimal treatment modalities and the sequence in which they are performed are largely dependent on histology. In most cases, olfactory neuroblastoma is best managed with surgical resection followed by radiation therapy. Sinonasal neuroendocrine carcinomas represent a variety of histologic phenotypes (carcinoid, atypical carcinoid, small cell, and large cell), which determine the optimal treatment modality. Finally, sinonasal undifferentiated carcinoma is likely best managed by induction chemotherapy with subsequent therapy dictated by the initial response.

CONCLUSIONS

A team approach to multi-modality care is essential in the treatment of olfactory neuroblastoma, sinonasal neuroendocrine carcinoma, and sinonasal undifferentiated carcinoma. Early biopsy, histologic diagnosis, and comprehensive imaging are critical to determining the appropriate management paradigm.

Sinonasal Undifferentiated Carcinoma (SNUC): From an Entity to Morphologic Pattern and Back Again-A Historical Perspective

Since the first description of sinonasal undifferentiated carcinoma (SNUC) as a distinctive highly aggressive sinonasal neoplasm with probable origin from the sinonasal mucosa (Schneiderian epithelium), SNUC has been the subject of ongoing study and controversy. In particular, the SNUC category gradually became a "wastebasket" for any undifferentiated or unclassifiable sinonasal malignancy of definite or probable epithelial origin. However, with the availability of more specific and sensitive immunohistochemical antibodies and increasing implementation of novel genetic tools, the historical SNUC category became the subject of progressive subdivision leading to recognition of specific genetically defined, reproducible subtypes. These recently recognized entities are characterized by distinctive genetic aberrations including NUTM1-rearranged carcinoma (NUT carcinoma) and carcinomas associated with inactivation of different members of the SWI/SNF chromatin-remodeling gene complex such as SMARCB1-deficient and less frequently SMARCA4-deficient carcinoma. The ring became almost closed, with recent studies highlighting frequent oncogenic IDH2 mutations in the vast majority of histologically defined SNUCs, with a frequency of 82%. A review of these cases suggests the possibility that "true SNUC" probably represents a distinctive neoplastic disease entity, morphologically, phenotypically, and genetically. This review addresses this topic from a historical perspective, with a focus on recently recognized genetically defined subsets within the SNUC spectrum.

Neuroradiological and Neuropathological Changes After 177Lu-Octreotate Peptide Receptor Radionuclide Therapy of Refractory Esthesioneuroblastoma

BACKGROUND AND IMPORTANCE

Olfactory neuroblastoma, also known as esthesioneuroblastoma (ENB), is a malignant neoplasm with an unpredictable behavior. Currently, the widely accepted treatment is inductive chemotherapy, with or without surgery, followed by radiotherapy. Since data on genetics and molecular alterations of ENB are lacking, there is no standard molecularly targeted therapy. However, ENB commonly expresses the somatostatin receptor (SSTR) that is also expressed by neuroendocrine tumors. Peptide receptor radionuclide therapy (PRRT) using radiolabeled somatostatin analogues, such as 177Lu-octreotate, is an effective treatment for the latter. We present the complex neuroradiological and neuropathological changes associated with 177Lu-octreotate treatment of a patient with a highly treatment-resistant ENB.

CLINICAL PRESENTATION

A 60-yr-old male presented with an ENB that recurred after chemotherapy, surgery, stereotactic radiosurgery, and immunotherapy. Pathology revealed a Hyams grade 3 ENB and the tumor had metastasized to lymph nodes. Tumor SSTR expression was seen on 68Ga-octreotate positron emission tomography (PET)/computed tomography (CT), suggesting that PRRT may be an option. He received 4 cycles of 177Lu-octreotate over 6 mo, with a partial response of all lesions and symptomatic improvement. Four months after the last PRRT cycle, 2 of the lesions rapidly relapsed and were successfully resected. Three months later, 68Ga-octreotate PET/CT and magnetic resonance imaging indicate no progression of the disease.

CONCLUSION

We describe imaging changes associated with 177Lu-octreotate PRRT of relapsing ENB. To our knowledge, this is the first report describing neuropathological changes associated with this treatment. PRRT is a promising therapeutic option to improve the disease control, and potentially, the survival of patients with refractory ENB.

Evaluating the prognostic potential of the Ki67 proliferation index and tumour-infiltrating lymphocytes in olfactory neuroblastoma

AIMS

Olfactory neuroblastomas (ONBs) are rare malignant tumours that arise in the nasal vault. To date, the Hyams grade remains the only widely used histological grading system. However, it is based only on morphological criteria, and has not been updated since 1988. The objective of this study was to explore the prognostic potential of the Ki67 proliferation index (PI) and tumour-infiltrating lymphocytes (TILs) in ONB.

METHODS AND RESULTS

A retrospective study was conducted on a bicentric series of 45 cases. The Ki67 PI was determined by counting at least 1000 nuclei on whole slides. TILs were evaluated with CD20, CD4 and CD8 immunohistochemical markers on whole slides. In this series, Hyams grades I, II, III and IV accounted for 13.4%, 44.4%, 20% and 22.2% of all cases, respectively. The Ki67 PI ranged from 1 to 93; the Ki67 PI was significantly higher in Hyams grade III-IV ONBs than in Hyams grade I-II ONBs (P < 0.0001). A Ki67 PI of ≥25 was associated with poorer survival (P = 0.02). TILs were present in both stromal and intratumoral compartments, but were located predominantly in the stromal component of the tumour. The numbers of intratumoral CD8+ cells/mm² and CD4+ cells/mm² were greater in high-grade ONBs than in low-grade ONBs (P = 0.0015 and P = 0.043, respectively). The numbers of T cells/mm² and B cells/mm² were not associated with survival, but a CD4/CD8 ratio of >2 was significantly associated with shorter survival (P = 0.04).

CONCLUSION

Our findings suggest that the Ki67 PI and TILs could be used as prognostic markers, as a potential alternative to the Hyams grade.

DNA methylation-based classification of sinonasal undifferentiated carcinoma

Sinonasal undifferentiated carcinoma (SNUC) is an aggressive malignancy harboring IDH2 R172 mutations in >80% cases. We explored the potential of genome-wide DNA methylation profiling to elucidate tumor biology and improve the diagnosis of sinonasal undifferentiated carcinoma and its histologic mimics. Forty-two cases, including sinonasal undifferentiated, large cell neuroendocrine, small cell neuroendocrine, and SMARCB1-deficient carcinomas and olfactory neuroblastoma, were profiled by Illumina Infinium Methylation EPIC array interrogating >850,000 CpG sites. The data were analyzed using a custom bioinformatics pipeline. IDH2 mutation status was determined by the targeted exome sequencing (MSK-IMPACT^TM) in most cases. H3K27 methylation level was assessed by the immunohistochemistry-based H-score. DNA methylation-based semi-supervised hierarchical clustering analysis segregated IDH2 mutants, mostly sinonasal undifferentiated (n = 10) and large cell neuroendocrine carcinomas (n = 4), from other sinonasal tumors, and formed a single cluster irrespective of the histologic type. t-distributed stochastic neighbor embedding dimensionality reduction analysis showed no overlap between IDH2 mutants, SMARCB1-deficient carcinoma and olfactory neuroblastoma. IDH2 mutants demonstrated a global methylation phenotype and an increase in repressive trimethylation of H3K27 in comparison to IDH2 wild-type tumors (p < 0.001). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed no difference in pathway activation between IDH2-mutated sinonasal undifferentiated and large cell neuroendocrine carcinomas. In comparison to SMARCB1-deficient, IDH2-mutated carcinomas were associated with better disease-free survival (p = 0.034) and lower propensity for lung metastasis (p = 0.002). ARID1A mutations were common in small cell neuroendocrine carcinoma but not among IDH2 mutants (3/3 versus 0/18 and p < 0.001). IDH2 mutations in sinonasal carcinomas induce a hypermethylator phenotype and define a molecular subgroup of tumors arising in this location. IDH2-mutated sinonasal undifferentiated carcinoma and large cell neuroendocrine carcinoma likely represent a phenotypic spectrum of the same entity, which is distinct from small cell neuroendocrine and SMARCB1-deficient sinonasal carcinomas. DNA methylation-based analysis of the sinonasal tumors has potential to improve the diagnostic accuracy and classification of tumors arising in this location.

Translational genomics of sinonasal cancers

The sinonasal cavities harbor a wide variety of histologically distinct cancers, the majority very aggressive with 5-year survival rates between 30-60% and local recurrence as the main cause of death. This is a complex anatomic area, close to structures such the eyes and the brain, which is of special relevance for surgery and postoperative radiotherapy. The low incidence of these rare tumors hampers accumulation of experience with diagnosis and clinical managment as well as knowledge on recurrent genetic aberrations or testing of new treatment strategies. However, recent years have seen a growing number of publications on genetic aberrations providing data that can aid or fine-tune classification and provide molecular targets for treatment with specific inhibitors. In addition, new sinonasal cancer models are created that enable preclinical testing of candidate inhibitor drugs. With more and more novel targeted therapies being developed, options for personalized treatment of sinonasal cancer patients are now opening up.

[Neuroendocrine neoplasms of the auditory, olfactory, and visual sensory organs]

Neuroendocrine neoplasms (NENs) are infrequent in sensory organs. There are well-differentiated neuroendocrine neoplasms that should be classified as neuroendocrine tumors, in analogy to their gastrointestinal counterparts, however the nomenclature is inconsistent. The best defined entities are neuroendocrine tumors in the middle ear and ectopic pituitary adenoma in the sphenoid region. Poorly differentiated NENs most often arise in the olfactory organ and nasal cavity that are represented by olfactory neuroblastomas and poorly differentiated neuroendocrine carcinomas. They have several mimickers such as the sinonasal undifferentiated carcinoma, poorly differentiated squamous cell carcinoma, mucosal malignant melanoma, rhabdomyosarcoma, Ewing sarcoma/primitive neuroectodermal tumor and non-Hodgkin lymphoma.

Diagnostic traps awaiting the head/neck pathologist: "Cytoplasm-poor" neoplasms

CONTEXT

Beyond squamous carcinoma, a variety of diagnostically challenging neoplasms arise within various head and neck sites. This is particularly the situation with neoplasms where little cellular cytoplasm is present to assist the pathologist in categorizing such lesions.

OBJECTIVE

To highlight diagnostic pitfalls that accompanying neoplasms composed primarily of 'cytoplasmically-poor' cells. These pitfalls include morphologic and immunohistochemical traps that emerge from this class of neoplasms.

DATA SOURCES

Selection of pathologic specimens from the author's personal files, and literature review.

CONCLUSIONS

Interpretative pitfalls regarding the histopathology and immunophenotype of small 'cytoplasmically-poor' neoplasms are a diagnostic hazard in head and neck surgical pathology practice, and require knowledge of histomorphologic plasticity and aberrant immunophenotyping.

INSM1 is a Sensitive and Specific Marker of Neuroendocrine Differentiation in Head and Neck Tumors

The head and neck is the site of a wide and sometimes bewildering array of neuroendocrine (NE) tumors. Although recognition of NE differentiation may be necessary for appropriate tumor classification and treatment, traditional NE markers such as synaptophysin, chromogranin, and CD56 are not always sufficiently sensitive or specific to make this distinction. Insulinoma-associated protein 1 (INSM1) is a novel transcription factor that has recently demonstrated excellent sensitivity and specificity for NE differentiation in various anatomic sites, but has not yet been extensively evaluated in tumors of the head and neck. We performed INSM1 immunohistochemistry on NE tumors (n=97) and non-NE tumors (n=626) across all histologic grades and anatomic subsites of the head and neck. INSM1 was positive in all types of head and neck NE tumors evaluated here (99.0% sensitivity), including middle ear adenoma, pituitary adenoma, paraganglioma, medullary thyroid carcinoma, olfactory neuroblastoma, small cell carcinoma, large cell NE carcinoma, and sinonasal teratocarcinosarcoma. Notably, it was positive in the vast majority of high-grade NE malignancies (95.8% sensitivity). INSM1 also was negative in almost all non-NE tumors (97.6% specificity) with the highest rates of reactivity in alveolar rhabdomyosarcoma and SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily B, member 1 (SMARCB1)-deficient sinonasal carcinoma. These findings confirm that INSM1 may be used as a standalone first-line marker of NE differentiation for tumors of the head and neck.

Sinonasal Undifferentiated Carcinoma

PURPOSE OF REVIEW

To provide a comprehensive review of the literature highlighting the recent advances in the diagnosis and management of sinonasal undifferentiated carcinoma (SNUC) RECENT FINDINGS: SNUC usually presents at advanced stage and the prognosis is usually poor with high rates of locoregional recurrence and tendency to metastasize. Special attention should be made in differentiating SNUC from other sinonasal malignancies in order to guide the appropriate treatment accordingly. Multimodality treatment is usually recommended for treating SNUC. The use of neoadjuvant chemotherapy may be associated with improved outcome and can be used to guide the subsequent treatment selection. Despite the recent advances in chemotherapeutic agents, radiation techniques, and surgical approaches, the prognosis and survival outcomes of SNUC remain poor. The addition of induction chemotherapy to the treatment approach followed by definitive local therapy needs to be further studied as it might improve the outcome.

Large cell neuroendocrine carcinoma of the nasal cavity: an extremely rare and new distinct entity

Large cell neuroendocrine carcinoma (LCNEC) is a rare but distinct entity of nasal cavity carcinomas. Only a very few cases have been reported in the nasal cavity. Its treatment is not well established. We report the case of a LCNEC in a 70 years old patient who presented with right nasal obstruction and epistaxis since 2 months. Diagnosis was confirmed by histological and immunohistochemical study. The patient underwent complete endoscopic removal of the tumor combined to adjuvant chemoradiotherapy. After 6 month follow-up, the patient was in complete clinical and radiological remission. We will discuss in this paper the various epidemiology, clinical features, pathological findings, differential diagnosis, and evolution of treatment of this uncommon malignancy in the light of current knowledge. Optimal treatment strategies are yet to be determined for this rare malignancy with poor prognosis including surgery and chemoradiotherapy.

Imaging review of the anterior skull base

The anterior skull base (ASB) is intimately associated with the unique soft tissue subtypes of the nasal cavity, paranasal sinuses, orbits, and intracranial compartment. Pathology involving the ASB is rare but the causes are manifold and can be broadly subdivided into those intrinsic to the skull base and processes extending from below or above. Sinonasal pathology is the most commonly encountered and poses significant management challenges that rely heavily on accurate interpretation of the radiological findings. We illustrate the normal anatomy of the ASB and present a cross-sectional imaging review of the pathological entities that may be encountered, focusing on the specific features that will impact on clinical and surgical management.

Genetic profiling of poorly differentiated sinonasal tumours

The sinonasal cavities harbour a variety of rare tumour types. Many carry a poor prognosis while therapeutic options are limited. Histopathological classification can be difficult, especially for poorly differentiated tumours such as olfactory neuroblastoma (ONB), sinonasal neuroendocrine carcinoma (SNEC) and sinonasal undifferentiated carcinoma (SNUC). We analysed Affymetrix OncoScan genome-wide copy number profiles of these three tumour types, both as originally diagnosed and as regrouped by their cytokeratin (Ck) and neuroendocrine (Ne) expression pattern, aiming to find a relation between phenotype and genotype. According to the original histopathological classification our series consisted of 24 ONB, 11 SNEC and 19 SNUC, while immunohistochemistry indicated 11 Ck−Ne+/ONB, 18 Ck+Ne+/SNEC, 24 Ck+Ne−/SNUC, and 1 Ck−Ne−/unclassified. As originally diagnosed, the three tumour types showed similar copy number profiles. However, when regrouped by Ck/Ne immunostaining we found a distinct set of gains and losses; Ck−Ne+/ONB harboured few and predominantly whole chromosomes abnormalities, Ck+Ne+/SNEC carried both gains and losses in high frequency, and Ck+Ne−/SNUC showed mostly gains. In addition, each tumour carried a number of unique chromosomal deletions. Genome-wide copy number profiling supports the value of immunohistochemical CkNe staining of ONB, SNEC and SNUC for tumour classification, which is important for prognosis and therapeutic decision-making.

Sinonasal Neuroendocrine Neoplasms: Current Challenges and Advances in Diagnosis and Treatment, with a Focus on Olfactory Neuroblastoma

Sinonasal tumors with neuroendocrine differentiation form a group of rare heterogeneous neoplasms of neuroectodermal and epithelial origin, consisting of olfactory neuroblastomas and neuroendocrine carcinomas. Because the natural history and biological behavior of this group of tumors vary, the morphological diagnosis coupled with grading/staging is important for prognostication, and the approach to treatment and rehabilitation is multidisciplinary. The identification of molecular abnormalities underlying these tumors is critical to the development of specific targeted therapies and the design of clinical trials.

Genetic and molecular alterations in olfactory neuroblastoma: implications for pathogenesis, prognosis and treatment

Olfactory neuroblastoma (ONB, Esthesioneuroblastoma) is an infrequent neoplasm of the head and neck area derived from olfactory neuroepithelium. Despite relatively good prognosis a subset of patients shows recurrence, progression and/or metastatic disease, which requires additional treatment. However, neither prognostic nor predictive factors are well specified. Thus, we performed a literature search for the currently available data on disturbances in molecular pathways, cytogenetic changes and results gained by next generation sequencing (NGS) approaches in ONB in order to gain an overview of genetic alterations which might be useful for treating patients with ONB. We present briefly ONB molecular pathogenesis and propose potential therapeutic targets and prognostic factors. Possible therapeutic targets in ONB include: receptor tyrosine kinases (c-kit, PDGFR-b, TrkB; EGFR); somatostatin receptor; FGF-FGFR1 signaling; Sonic hedgehog pathway; apoptosis-related pathways (Bcl-2, TRAIL) and neoangiogenesis (VEGF; KDR). Furthermore, we compare high- and low-grade ONB, and describe its frequent mimicker: sinonasal neuroendocrine carcinoma. ONB is often a therapeutic challenge, so our goal should be the implementation of acquired knowledge into clinical practice, especially at pretreated, recurrent and metastatic stages. Moreover, the multicenter molecular studies are needed to increase the amount of available data.

Diagnostic reliability of pretreatment biopsy in malignant nasoethmoidal tumors: A retrospective study of 77 cases

OBJECTIVES/HYPOTHESIS

Pretreatment biopsy is crucial in histology-based management of malignant nasoethmoidal tumors, because misdiagnosis can lead to inadequate therapeutic planning. Factors influencing the reliability of biopsy were retrospectively investigated in a tertiary referral center.

STUDY DESIGN

Retrospective case series.

METHODS

All patients who underwent biopsy, staging magnetic resonance, surgery, and histologic diagnosis for nasoethmoidal tumors in our hospital were retrospectively evaluated. Histologic discrepancy, histology, procedure for biopsy (biopsy under local anesthesia [OB], biopsy under local anesthesia and sedation [SB], or under general anesthesia [GB]), site of the lesion, and the biopsy volume were analyzed. Biopsy reliability rate (BRR) (preoperative biopsy confirmed after surgical treatment) and concordance rate (CR) (postoperative diagnosis identified in preoperative biopsy) were calculated. Univariate and multivariate statistical analyses were used to identify factors influencing histologic discrepancies.

RESULTS

Seventy-seven patients were included. Five (6.5%) minor and eight (10.4%) major histologic discrepancies were observed (16.9%). OB and SB showed significantly lower biopsy volumes than GB (P < .0001 and P = .002, respectively). The biopsy volume was significantly lower in cases with histologic discrepancies (P = .045). Squamous cell carcinoma was independently associated with lower BRR. Germ cell tumor, salivary gland carcinoma, and sarcoma showed the lowest CR. Adenocarcinoma, mucosal melanoma, and olfactory neuroblastoma showed the highest BRR and CR.

CONCLUSIONS

The risk of misdiagnosis for nasoethmoidal tumors may be high even in referral centers. Especially when clinical and radiologic findings suggest a diagnosis different from adenocarcinoma, mucosal melanoma, and olfactory neuroblastoma, obtaining abundant material under general anesthesia may reduce the risk of diagnostic error and inadequate treatment.

LEVEL OF EVIDENCE

4. Laryngoscope, 1772-1777, 2018.

The Impact of Histologic Phenotype in the Treatment of Sinonasal Cancer

The management of sinonasal cancer is a challenge due to its low occurrence and anatomical and significant diversity of histological types. The therapeutic modality used should be tailored individually according to the histology, tumour stage, molecular profile and previous treatments. The clinical management of sinonasal cancer has improved greatly owing to developments in endoscopic surgery and precision radiotherapy. Complete surgical resection is the mainstay of sinonasal malignancies' management but multimodality therapy is associated with improved outcomes in certain histologies. The recognition of various histological types with biological behaviours more suitable for non-surgical modalities has allowed treatment protocols to become more tailored to the disease. In this review we aim to describe and to summarise the current data guiding the management of sinonasal cancer with emphasis on phenotypic variation.

Staging of Sinonasal and Ventral Skull Base Malignancies

Tremendous pathologic diversity among sinonasal and ventral skull base malignancies complicates development of a uniform and prognostically relevant staging system. Because of the comparatively low incidence of these tumors, comprehensive evaluation and comparison of specific staging systems is difficult. The current American Joint Committee on Cancer TNM staging system for sinonasal malignancies is the most common and widely used system in current clinical practice. Alternative systems have been proposed for use with individual histopathologic subtypes. Many of these staging systems are of great utility and accurately predict patient survival. Further research and adjustment of these current staging systems remains an important area of research.

Serotonin, ATRX, and DAXX Expression in Pituitary Adenomas: Markers in the Differential Diagnosis of Neuroendocrine Tumors of the Sellar Region

Differential diagnosis based on morphology and immunohistochemistry between a clinically nonfunctioning pituitary neuroendocrine tumor (NET)/pituitary adenoma and a primary or secondary NET of nonpituitary origin in the sellar region may be difficult. Serotonin, a frequently expressed marker in the NETs, has not been systematically evaluated in pituitary NETs. Although mutations in ATRX or DAXX have been reported in a significant proportion of pancreatic NETs, the mutational status of ATRX and DAXX and their possible pathogenetic role in pituitary NETs are unknown. Facing a difficult diagnostic case of an invasive serotonin and adrenocorticotroph hormone immunoreactive NET in the sellar region, we explored the immunohistochemical expression of serotonin, ATRX, and DAXX in a large series of pituitary endocrine tumors of different types from 246 patients and in 2 corticotroph carcinomas. None of the pituitary tumors expressed serotonin, suggesting that serotonin immunoreactive sellar tumors represent primary or secondary NETs of nonpituitary origin. Normal expression of ATRX and DAXX in pituitary tumors suggests that ATRX and DAXX do not play a role in the pathogenesis of pituitary endocrine tumors that remain localized to the sellar and perisellar region. A lack of ATRX or DAXX in a sellar NET suggests a nonpituitary NET, probably of pancreatic origin. One of the 2 examined corticotroph carcinomas, however, demonstrated negative ATRX immunolabeling due to an ATRX gene mutation. Further studies on a larger cohort of pituitary carcinomas are needed to clarify whether ATRX mutations may contribute to the metastatic potential in a subset of pituitary NETs.

Simultaneous integrated prophylactic cranial irradiation in sino-nasal cancer

Therapy for small cell cancer and high grade neuroendocrine tumours of the paranasal sinuses is extrapolated from the treatment of small cell lung cancer and paranasal cancer of different histologies. Prophylactic cranial irradiation has proven survival benefit in small cell lung cancer. Two patients with aggressive cancer of the paranasal sinuses received radiotherapy with simultaneous integrated prophylactic brain irradiation, using two sequential plans. Chemotherapy was given before, during and after radiotherapy. None of the patients had intracranial recurrence. One patient experienced severe, but transient encephalitis-like symptoms that could only be attributed to radiotherapy. No long term side effects in the CNS were observed. The treatment was feasible, but with possible severe, but transient side effects. It should be considered in cases with head and neck cancer, with a high risk of intracerebral metastasis, as well as a significant overlap between the primary irradiated volume and the brain.

Small round blue cell tumors of the sinonasal tract: a differential diagnosis approach

One of the most challenging diagnostic categories within tumors of the sinonasal tract is the small round blue cell tumors. Biopsies are usually small and limited, resulting in considerable diagnostic difficulty for practicing surgical pathologists. These tumors share several overlapping histologic and immunophenotypic findings while also showing considerable variation within and between cases. Specific tumor site of origin, imaging findings, and clinical findings must be combined with the histology and pertinent ancillary studies if the correct diagnosis is to be reached. Discrimination between neoplasms is critical as there are significant differences in therapy and overall outcome. It is important to have a well developed differential diagnosis for this category of tumors, where each of the diagnoses is considered, evaluated, and either confirmed or excluded from further consideration. In an undifferentiated tumor, showing a small round blue cell morphology, using the mnemonic 'MR SLEEP' helps to highlight tumors to consider: melanoma, mesenchymal chondrosarcoma, rhabdomyosarcoma, sinonasal undifferentiated carcinoma, squamous cell carcinoma (including NUT carcinoma), small cell osteosarcoma, lymphoma, esthesioneuroblastoma (olfactory neuroblastoma), Ewing sarcoma/primitive neuroectodermal tumor, pituitary adenoma, and plasmacytoma. A panel of pertinent immunohistochemistry studies, histochemistries and/or molecular tests should aid in reaching a diagnosis, especially when taking the pattern and intensity of reactions into consideration.

Sinonasal Small Round Blue Cell Tumors: An Immunohistochemical Approach

Although clinical history and morphologic appearance should be the initial considerations when evaluating small round blue cell tumors of the sinonasal tract, the final diagnosis often hinges on immunohistochemical findings. Unfortunately, interpretation of stains in these tumors is fraught with numerous pitfalls and limitations. This article presents an approach to sinonasal small round blue cell tumors based on four common immunohistochemical patterns: cytokeratin positivity, squamous marker positivity, neuroendocrine marker positivity, and cytokeratin negativity.

An isolated orbital mass with proptosis and diplopia: an uncommon metastasis from intracranial olfactory neuroblastoma in a chinese patient

Purpose

Olfactory neuroblastoma (ONB) is a rare neuroectodermal malignant neoplasm that originates from the olfactory sensory epithelium. In reported cases involving the orbit, the primary neoplasms could invade the orbits through bone destruction or cranio-orbital communication anatomical structure. The present study reports a rare case of orbital metastatic tumor arising from an intracranial ONB in a Chinese patient, which is the first case demonstrating an uncommon route of ONB involving the orbit.

Patient and methods

A 62-year-old man with a right orbital tumor was diagnosed as having a secondary tumor arising from intracranial ONB. Clinical examination, including ocular imaging examination, and histopathological and immunohistochemical studies were performed.

Results

In the ocular examination, a focal, firm, nontender swelling with ill-defined margins in the right orbit was found on palpation. Proptosis, limited eyeball movement, and visual loss were also observed. The unenhanced computed tomography scan showed a homogeneous, isolated, ill-defined soft tissue neoplasm in the right orbit. The histopathological study revealed irregularly shaped nests of tumor cells surrounded by avascularized fibrous stroma. The monomorphic malignant tumor cells are small round blue cells that are slightly larger than mature lymphocytes, with a very high nuclear to cytoplasmic ratio. The immunohistochemical staining for tumor cells was positive for synaptophysin, chromogranin A, cluster of differentiation 56 (CD56), cytokeratin, vimentin, S-100 protein, and negative for epithelial membrane antigen, and cluster of differentiation (CD99).

Conclusion

This is so far the first Chinese case of orbital metastasis from intracranial ONB that has ever been reported. Metastasis might be another route of ONB invading the orbit besides direct invasion.

Neuroendocrine Neoplasms of the Sinonasal Tract: Neuroendocrine Carcinomas and Olfactory Neuroblastoma

Neuroendocrine neoplasms (NENs) can occur in organs or tissues that do not contain neuroendocrine cells normally and do not necessarily imply embryologic derivation from the neuroectoderm; but rather reflect a shared phenotype characterized by the expression of multiple genes encoding both endocrine and neuronal features. NENs are rare in the sinonasal tract and are subdivided into epithelial and neural subtypes based on the presence of keratins or neurofilaments, respectively. Although relatively rare, neuroendocrine carcinomas (NECs) and olfactory neuroblastoma (ONB) are the most common neuroendocrine neoplasms of the sinonasal tract. The focus of this review is to highlight recent developments in the pathology of sinonasal NECs and ONB in light of the upcoming update of the World Health Organization (WHO) 2005 classification of tumors of the head and neck.