Neuroectodermal neoplasms of the head and neck with emphasis on neuroendocrine carcinomas

Top IHC/ISH Hacks for and Molecular Surrogates of Poorly Differentiated Sinonasal Small Round Cell Tumors

BACKGROUND

Poorly differentiated sinonasal small round cell tumors (SRCTs) are rare and heterogeneous, posing challenges in diagnosis and treatment.

METHODS

Recent advances in molecular findings and diagnostic refinement have promoted better understanding and management of these tumors.

RESULTS

The newly defined and emerging sinonasal entities demonstrate diverse morphologies, specific genomic signatures, and clinical behavior from conventional counterparts. In this review of SRCTs, emphasis is placed on the diagnostic approach with the employment of a pertinent panel of immunohistochemistry studies and/or molecular tests, fine-tuned to the latest WHO 5 classification of sinonasal/paranasal tumors and personalized treatment.

CONCLUSION

Specifically, this review focuses on tumors with epithelial and neuroectodermal derivation.

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.

Top 10 Histological Mimics of Neuroendocrine Carcinoma You Should Not Miss in the Head and Neck

BACKGROUND

The spectrum of neuroendocrine neoplasia (NEN) of the head and neck region is wide-ranging and diverse, including a variety of diagnoses stretching from benign and low-malignant tumor forms to highly proliferative, poor prognosis neuroendocrine carcinoma (NEC). Moreover, there are several non-neuroendocrine differential diagnoses to keep in mind as well, displaying various degree of morphological and/or immunohistochemical overlap with bona fide neuroendocrine lesions.

METHODS

Review.

RESULTS

While the growth patterns may vary, well-differentiated NEN usually display a stippled "salt and pepper" chromatin, a granular cytoplasm, and unequivocal expression of neuroendocrine markers such as chromogranin A and synaptophysin. However, these features are often less pronounced in NEC, which may cause diagnostic confusion-not the least since several non-NEC head and neck tumors may exhibit morphological similarities and focal neuroendocrine differentiation.

CONCLUSION

As patients with NEC may require specific adjuvant treatment and follow-up, knowledge regarding differential diagnoses and potential pitfalls is therefore clinically relevant. In this review, the top ten morphological and/or immunohistochemical mimics of NEC are detailed in terms of histology, immunohistochemistry, and molecular genetics.

Top 10 Nested Pattern Head and Neck Lesions to Notice

BACKGROUND

Nested is defined as "cellular clusters arranged in small groupings with intervening vascular or stromal networks, lacking lumens or glandular formation." Using this definition, multiple neoplastic and non-neoplastic lesions of the head and neck come into the differential. We have broadly organized the differential diagnosis of "nested" tumors into entities with neuroendocrine differentiation, squamous differentiation, thyroid follicular cell differentiation, and other lesions.

METHODS

Review.

RESULTS

Many different entities have a nested appearance and the morphologic, immunohistochemical, clinical, and radiographic features contribute to the differential diagnosis. The different tumors covered in this review include neuroendocrine neoplasms, paraganglioma, middle ear neuroendocrine tumor (formerly known as middle ear adenoma), medullary thyroid carcinoma, poorly differentiated thyroid carcinoma, olfactory neuroblastoma, ectopic pituitary neuroendocrine tumor, hyalinizing trabecular tumor, solid subtype of papillary thyroid carcinoma, solid cell nests/C-cell hyperplasia, necrotizing sialometaplasia, and meningioma.

CONCLUSION

In this review, we discuss the morphologic and immunohistochemical features of the covered entities as a guide to differential diagnosis when nested-patterned head and neck lesions are encountered.

Top 10 Basaloid Neoplasms of the Sinonasal Tract

BACKGROUND

Basaloid neoplasms of the sinonasal tract represent a significant group of tumors with histological overlap but often with different etiologies (i.e., viral, genetics), clinical management, and prognostic significance.

METHODS

Review.

RESULTS

"Basaloid" generally refers to cells with coarse chromatin in round nuclei and sparse cytoplasm, resembling cells of epithelial basal layers or imparting an "immature" appearance. Tumors with this characteristic in the sinonasal tract are represented by a spectrum of benign to high-grade malignant neoplasms, such as adenoid cystic carcinoma, NUT carcinoma, sinonasal undifferentiated carcinoma, SWI/SNF complex-deficient carcinomas, and adamantinoma-like Ewing sarcoma.

CONCLUSION

In some instances, histology alone may be sufficient for diagnosis. However, limited biopsy material or fine-needle aspiration specimens may be particularly challenging. Therefore, often other diagnostic procedures, including a combination of histology, immunohistochemistry (IHC), DNA and RNA testing, and molecular genetics are necessary to establish an accurate diagnosis.

Secondary Sinonasal Collision Tumor of Papillary Squamous Cell Carcinoma and Small Cell Neuroendocrine Carcinoma After Nasopharyngeal Carcinoma Radiotherapy: A Case Report and Literature Review of Sinonasal Collision Carcinomas

In the head and neck region, small cell neuroendocrine carcinoma (SmNEC) is extraordinary infrequent. Collision malignancy is also a rare entity in the nasal cavity, with merely sporadic 6 case reports on primary collision tumor associated with neuroendocrine carcinoma. The development of a secondary SmNEC within the previous radiation field had uncommonly been described, and there was no report on secondary sinonasal collision carcinoma with SmNEC component as a side reaction of nasopharyngeal carcinoma (NPC) radiotherapy. In light of the rarity of these neoplasms, we presented a case of a sinonasal collision carcinoma of papillary squamous cell carcinoma (PSCC) and SmNEC after NPC radiotherapy. To our knowledge, it may be the first case of a secondary coexistence of two malignancies synchronously in the nasal cavity after NPC treatment. Recognizing this peculiar kind of collision tumor associated SmNEC could promote our understanding of this entity and hence propose optimal treatment strategies.

Primary mucosal melanoma of the larynx: systematic review of the literature and qualitative synthesis

PURPOSE

Primary mucosal melanoma of the larynx (PLM) is a rare entity among head and neck cancers. Due to its rarity, clear protocols of management are not available. A deeper knowledge of the clinical and biological behaviour of PLM is strongly needed.

METHODS

According to PRISMA process, we searched through electronic databases case reports, case series and review articles providing relevant clinical data. The survival analysis was performed with Kaplan-Meier survival curves, using disease free survival (DFS) and overall survival (OS) as endpoints.

RESULTS

1074 articles were initially screened, of which 37 studies describing 44 PLM cases were selected and included in the analysis. Mean age was 59.7 years with a mean follow-up time of 25.4 months. The most common symptom at presentation was hoarseness (52%), while the most involved laryngeal subsite was supraglottic region (62%). Most patients presented with an advanced stage. Tumour (T) and node (N) status at presentation did not influence OS nor DFS, whereas distant metastases (M) status resulted significantly associated with the reduction of OS and DFS time (Mantel-Cox: p < 0.0001 and p = 0.001, respectively). The laryngeal subsite and the type of surgery performed did not significantly impact on OS and DFS.

CONCLUSIONS

Treatment for PLM remains debated. Surgery with safe margins is recommended due to the high rates of local recurrence. Systemic therapy is advised for metastatic disease. However, the prognosis remains poor even after radical resection or targeted therapy.

Head and neck small-cell carcinoma: A multicenter study of 39 cases from 10 institutions

Objective

Basal information of head and neck small-cell carcinoma (HNSmCC) including epidemiology, primary site, treatment, and prognosis remains sparse due to its rarity. We report here a multicenter retrospective study on the diagnosis, treatment, and outcomes of patients with HNSmCC.

Materials and methods

This study involved 47 patients with HNSmCC from 10 participating institutions. Eight patients were excluded for whom no pathological specimens were available (n = 2) and for discrepant central pathological judgements (n = 6). The remaining 39 patients were processed for data analysis.

Results

As pretreatment examinations, computed tomography (CT) was performed for the brain (n = 8), neck (n = 39), and chest (n = 32), magnetic resonance imaging (MRI) for the brain (n = 4) and neck (n = 23), positron emission tomography-CT (PET-CT) in 23 patients, bone scintigraphy in 4, neck ultrasonography in 9, and tumor markers in 25. Primary sites were oral cavity (n = 1), nasal cavity/paranasal sinuses (n = 16), nasopharynx (n = 2), oropharynx (n = 4), hypopharynx (n = 2), larynx (n = 6), salivary gland (n = 3), thyroid (n = 2), and others (n = 3). Stages were II/III/IV-A/IV-B/IV-C/Not determined = 3/5/16/6/5/4; stage IV comprised 69%. No patient had brain metastases. First-line treatments were divided into 3 groups: the chemoradiotherapy (CRT) group (n = 27), non-CRT group (n = 8), and best supportive care group (n = 4). The CRT group included concurrent CRT (CCRT) (n = 17), chemotherapy (Chemo) followed by radiotherapy (RT) (n = 5), and surgery (Surg) followed by CCRT (n = 5). The non-CRT group included Surg followed by RT (n = 2), Surg followed by Chemo (n = 1), RT alone (n = 2), and Chemo alone (n = 3). The 1-year/2-year overall survival (OS) of all 39 patients was 65.3/53.3%. The 1-year OS of the CRT group (77.6%) was significantly better compared with the non-CRT group (31.3%). There were no significant differences in adverse events between the CCRT group (n = 22) and the Chemo without concurrent RT group (n = 9).

Conclusion

Neck and chest CT, neck MRI, and PET-CT would be necessary and sufficient examinations in the diagnostic set up for HNSmCC. CCRT may be recommended as the first-line treatment. The 1-year/2-year OS was 65.3%/53.3%. This study would provide basal data for a proposing the diagnostic and treatment algorithms for HNSmCC.

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.

Combined Neuroendocrine and Squamous Cell Carcinoma of the Sinonasal Tract: A Morphologic and Immunohistochemical Analysis and Review of Literature

Sinonasal malignancies constitute 3% of head and neck cancers, with squamous cell carcinoma (SCC) the most common histology. Neuroendocrine carcinomas (NEC) are rare, with a subset showing neuroendocrine carcinoma and a non-neuroendocrine component. The pathogenesis of these combined tumors is largely unknown, and TP53 driver mutations may play a role. A database search for combined NEC was performed across two institutions (UNM and UCSF) spanning 15 years. Excluding NUT midline carcinoma, 3 cases met inclusion criteria. All were morphologically NEC + SCC and underwent a comprehensive immunohistochemical evaluation. Tumors demonstrated two components histologically: moderately to poorly differentiated SCC and high-grade NEC. Divergent differentiation was confirmed with lineage-specific markers. Only one patient received neoadjuvant chemotherapy prior to surgery, with a remarkable response (a marked decrease in the size of the primary lesion and resolution of liver metastases). Immunohistochemical staining for p53 was increased in 2 of 3 cases (both components), suggesting a role in the carcinogenesis of these tumors. Aberrant expression of beta-catenin was not identified. One case tested positive for p16, which can be seen in high grade NECs due to inactivation of Rb gene. Additionally, both cases with a small cell NEC component expressed PD-L1, suggesting that immunotherapy may be an effective treatment. Findings in this study support the role of p53 mutation in a subset of combined NEC + SCC of the sinonasal tract. Recognition of this rare entity is essential for optimal management of these aggressive neoplasms.

Large cell neuroendocrine carcinoma of the floor of mouth and retromolar trigone in association with basaloid squamous cell carcinoma

Large cell neuroendocrine carcinoma and basaloid squamous cell carcinoma are each rare but aggressive diseases of the head and neck. A case of large cell neuroendocrine carcinoma occurring simultaneously with a basaloid squamous cell carcinoma originating from the oral cavity is described in this report. The diagnosis of these pathologies can be challenging but is important, as staging and treatment recommendations differ from those for oral cavity squamous cell carcinoma.

Update from the 5th Edition of the World Health Organization Classification of Head and Neck Tumors: Overview of the 2022 WHO Classification of Head and Neck Neuroendocrine Neoplasms

This review article provides a brief overview of the new WHO classification by adopting a question-answer model to highlight the spectrum of head and neck neuroendocrine neoplasms which includes epithelial neuroendocrine neoplasms (neuroendocrine tumors and neuroendocrine carcinomas) arising from upper aerodigestive tract and salivary glands, and special neuroendocrine neoplasms including middle ear neuroendocrine tumors (MeNET), ectopic or invasive pituitary neuroendocrine tumors (PitNET; formerly known as pituitary adenoma) and Merkel cell carcinoma as well as non-epithelial neuroendocrine neoplasms (paragangliomas). The new WHO classification follows the IARC/WHO nomenclature framework and restricts the diagnostic term of neuroendocrine carcinoma to poorly differentiated epithelial neuroendocrine neoplasms. In this classification, well-differentiated epithelial neuroendocrine neoplasms are termed as neuroendocrine tumors (NET), and are graded as G1 NET (no necrosis and < 2 mitoses per 2 mm²; Ki67 < 20%), G2 NET (necrosis or 2-10 mitoses per 2 mm², and Ki67 < 20%) and G3 NET (> 10 mitoses per 2 mm² or Ki67 > 20%, and absence of poorly differentiated cytomorphology). Neuroendocrine carcinomas (> 10 mitoses per 2 mm², Ki67 > 20%, and often associated with a Ki67 > 55%) are further subtyped based on cytomorphological characteristics as small cell and large cell neuroendocrine carcinomas. Unlike neuroendocrine carcinomas, head and neck NETs typically show no aberrant p53 expression or loss of RB reactivity. Ectopic or invasive PitNETs are subtyped using pituitary transcription factors (PIT1, TPIT, SF1, GATA3, ER-alpha), hormones and keratins (e.g., CAM5.2). The new classification emphasizes a strict correlation of morphology and immunohistochemical findings in the accurate diagnosis of neuroendocrine neoplasms. A particular emphasis on the role of biomarkers in the confirmation of the neuroendocrine nature of a neoplasm and in the distinction of various neuroendocrine neoplasms is provided by reviewing ancillary tools that are available to pathologists in the diagnostic workup of head and neck neuroendocrine neoplasms. Furthermore, the role of molecular immunohistochemistry in the diagnostic workup of head and neck paragangliomas is discussed. The unmet needs in the field of head and neck neuroendocrine neoplasms are also discussed in this article. The new WHO classification is an important step forward to ensure accurate diagnosis that will also form the basis of ongoing research in this field.

Oral and Maxillofacial Neuroendocrine Carcinoma: A Systematic Review

The aim of the present study was to integrate the available data published in the literature on oral and maxillofacial neuroendocrine carcinomas concerning the demographic, clinical and histopathological features of this condition. An electronic search with no publication date restriction was undertaken in April 2021 in four databases. Eligibility criteria included reports published in English having enough data to confirm a definite diagnosis, always showing a neuroendocrine marker. Cases originating in the oropharynx, including base of the tongue and tonsils, were excluded. Outcomes were evaluated by the Kaplan-Meier method along with Cox regression. Twenty-five articles (29 cases) from nine different countries were detected. Mean patient age was 56.3 (± 17.5) years, with a slight male predilection. Symptomatology was present in 72.2% of informed cases. Regarding clinical presentation, a non-ulcerated nodule located in the gingiva with a mean size of 3.4 (± 2.0) cm was most frequently reported. Concomitant metastasis was identified in seven individuals. Histopathologically, most neoplasms were of the small cell type, and immunohistochemistry for both epithelial and neuroendocrine differentiation was used in 65.5% cases. Radical surgery was the treatment of choice in almost all cases, with or without adjuvant therapy. Mean follow-up was 20.5 (± 21.2) months, and only four patients developed recurrences. Eleven (44.0%) individuals died due to the disease. Ulcerated lesions were a prognostic factor. This study provides knowledge that can assist surgeons, oncologists, and oral and maxillofacial pathologists with the diagnosis and management of neuroendocrine carcinomas. Our findings demonstrated that the long-term prognosis of this lesion continues to be poor.

Neuroectodermal tumours of the sino-nasal tract: a clinicopathological study of 18 cases with a newly proposed revised classification and a brief review of literature

AIM

Sino-nasal tract tumours constitute 3% of the head and neck malignancies. Among these tumours, neuroectodermal tumours are rare with histo-morphological and immunohistochemical overlap making them a challenge for the pathologist. We included Ewing's/PNET, olfactory neuroblastoma (OFN), mucosal malignant melanomas (MMM), Melanotic neuroectodermal tumour of infancy (MNTI), small-cell neuroendocrine carcinoma (SNEC), and the newest entity Adamantinoma like Ewing's sarcoma (ALES) as part of the neuroectodermally derived tumours of the sino-nasal tract. The last three entities were added to the existing ones, which also has been emphasized in this paper.

METHODS AND RESULTS

A comprehensive analysis was done on all neuroectodermally derived tumours from 2016 to 2020. A total of 18 cases were collected, which included OFN (10 cases), SNEC (2 cases), MMM (2 cases), Ewing's/PNET (2 cases), MNTI (1 case), and ALES (1 case). The most common presentation in NE tumours was nasal obstruction (80-100%). Except for OFN, all other tumours were confined to the nasal and paranasal sinuses. 4/10 cases of OFN showed orbital extension. Cervical lymph-node metastasis was seen in 50% of cases of SNEC and MMM groups. An array of relevant immune-histochemical markers were performed. The marker expression was very subtle among the groups. On follow-up, recurrence was seen in the OFN and MMM groups in 30 and 50%, respectively. Metastasis was seen in SNEC group (100%) and OFN group (10%).

CONCLUSION

As sino-nasal neuroectodermal tumours pose a diagnostic challenge and have different therapies and are prognostically different, the pathologist must be aware of the subtle morphological, immunohistochemical clues which have been dealt with in-depth in this study.

IDH2 R172 Mutations Across Poorly Differentiated Sinonasal Tract Malignancies: Forty Molecularly Homogenous and Histologically Variable Cases With Favorable Outcome

IDH2 R172 mutations occur in sinonasal undifferentiated carcinoma (SNUC), large-cell neuroendocrine carcinoma (LCNEC), sinonasal adenocarcinomas, and olfactory neuroblastoma (ONB). We performed a clinical, pathologic, and genetic/epigenetic analysis of a large IDH2-mutated sinonasal tumor cohort to explore their distinct features. A total 165 sinonasal/skull base tumors included 40 IDH2 mutants studied by light microscopy, immunohistochemistry, and genome-wide DNA methylation, and 125 IDH2 wild-type tumors used for comparison. Methylation profiles were analyzed by unsupervised hierarchical clustering, t-distributed stochastic neighbor embedding dimensionality reduction and assessed for copy number alterations (CNA). Thirty-nine histologically assessable cases included 25 (64.1%) SNUC, 8 (20.5%) LCNEC, 2 (5.1%) poorly differentiated adenocarcinomas, 1 (2.7%) ONB, and 3 (7.7%) IDH2-mutated tumors with ONB features. All cases were high-grade showing necrosis (82.4%), prominent nucleoli (88.9%), and median 21 mitoses/10 HPFs. AE1/AE3 and/or CAM 5.2 were positive in all and insulinoma-associated protein 1 (INSM1) in 80% cases. All IDH2 mutants formed one distinct group by t-distributed stochastic neighbor embedding dimensionality reduction separating from all IDH2 wild-type tumors. There was no correlation between methylation clusters and histopathologic diagnoses. Recurrent CNA included 1q gain (79.3%), 17p loss (75.9%), and 17q gain (58.6%). No CNA differences were observed between SNUC and LCNEC. IDH2 mutants showed better disease-specific survival than SMARCB1-deficient (P=0.027) and IDH2 wild-type carcinomas overall (P=0.042). IDH2-mutated sinonasal tumors are remarkably homogeneous at the molecular level and distinct from IDH2 wild-type sinonasal malignancies. Biology of IDH2-mutated sinonasal tumors might be primarily defined by their unique molecular fingerprint rather than by their respective histopathologic diagnoses.

Management and outcome of middle ear adenomatous neuroendocrine tumours: A systematic review

Middle ear adenomatous neuroendocrine tumours (MEANTs) are rare, unpredictable tumours. Although most MEANTs are characterized by a benign biological behaviour and indolent growth pattern, some studies have reported locally invasive and metastastic disease. Currently, the optimal management strategy for MEANTs remains subject of debate. The aim of this study is to review the literature on MEANTs with focus on its clinical characteristics, treatment strategies and outcome. A systematic review was conducted using PubMed, Embase and Cochrane databases. A total of 111 studies comprising 198 patients with MEANT were included. Treatment modalities comprised surgery (90%), surgery with adjuvant radiotherapy (9%) and palliative (chemo)radiotherapy in (1%). Local recurrence was observed in 25% of the patients and 7% of the patients developed metastasis, over a median period of 5.7 years (range 7 months - 32 years). Twelve of 13 patients (92%) who developed metastases had a local recurrence. Four patients (2%) died of MEANT: three due to distant metastases and one due to extensive local recurrence. Reliable histopathologic predictors of outcome could not be identified. These findings indicate that the clinical presentations of MEANT vary substantially, the overall recurrence rate is considerable and initial local tumour control is paramount. Because of the unpredictable clinical course, prolonged follow-up is warranted.

Rare Diseases of the Nose, the Paranasal Sinuses, and the Anterior Skull Base

Due to their low incidence and thus resulting limited diagnostic criteria as well as therapeutic options, rare diseases of the nose, the paranasal sinuses, and the anterior skull base are a significant challenge. The value as of which a disease has to be considered as rare amounts to a maximum of 5 patients per 10 000 people. Within these diseases, however, there are extreme differences. Some rare or orphan diseases like for example the inverted papilloma belong to regularly diagnosed and treated diseases of larger departments of oto-rhino-laryngology whereas other rare diseases and malformations have only been described in less than 100 case reports worldwide. This fact emphasizes the necessity of bundling the available experience of diagnostics and therapy. The present article gives an overview about rare diseases of the nose, the paranasal sinuses, and the anterior skull base from the field of diseases/syndromes of the olfactory system, malformations of the nose and paranasal sinuses, ventilation and functional disorders as well as benign and malignant tumors. The classification and data on diagnostic and therapeutic options were established based on the current literature.

Nomograms Forecasting Long-Term Overall and Cancer Specific Survival of Patients With Head and Neck Neuroendocrine Carcinoma

Background

The purpose of this retrospective analysis was to build and validate nomograms to predict the cancer-specific survival (CSS) and overall survival (OS) of head and neck neuroendocrine carcinoma (HNNEC) patients.

Methods

A total of 493 HNNEC patients were selected from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2015, and 74 HNNEC patients were collected from the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University/Hunan Cancer Hospital (HCH) between 2008 and 2020. Patients from SEER were randomly assigned into training (N=345) and internal validation (N=148) groups, and the independent data group (N=74) from HCH was used for external validation. Independent prognostic factors were collected using an input method in a Cox regression model, and they were then included in nomograms to predict 3-, 5-, and 10-year CSS and OS rates of HNNEC patients. Finally, we evaluated the internal and external validity of the nomograms using the consistency index, while assessing their prediction accuracy using calibration curves. A receiver operating curve (ROC) was also used to measure the performance of the survival models.

Results

The 3-, 5-, and 10-year nomograms of this analysis demonstrated that M classification had the largest influence on CSS and OS of HNNEC, followed by the AJCC stage, N stage, age at diagnosis, sex/gender, radiation therapy, and marital status. The training validation C-indexes for the CSS and OS models were 0.739 and 0.713, respectively. Those for the internal validation group were 0.726 and 0.703, respectively, and for the external validation group were 0.765 and 0.709, respectively. The area under the ROC curve (AUC) of 3-, 5-, and 10-year CSS and OS models were 0.81, 0.82, 0.82, and 0.78, 0.81, and 0.82, respectively. The C-indexes were all higher than 0.7, indicating the high accuracy ability of our model's survival prediction.

Conclusions

In this study, prognosis nomograms in HNNEC patients were constructed to predict CSS and OS for the first time. Clinicians can identify patients' survival risk better and help patients understand their survival prognosis for the next 3, 5, and 10 years more clearly by using these nomograms.

Radiopharmaceuticals for Neuroendocrine Tumors

Neuroendocrine tumors (NETs) are a heterogeneous group of tumors that originate in endocrine tissues throughout the body. Peptide receptor radionuclide therapy (PRRT) has emerged as a promising therapeutic option for patients with locally advanced and/or metastatic disease refractory to standard of care treatment. The landmark international phase III NETTER-1 trial led to the approval of ¹⁷⁷Lu-DOTATATE (Lutathera) in the treatment of somatostatin receptor-positive gastroenteropancreatic NETs. Similarly, data from the multicenter, phase II Study IB12B led to the approval of meta-[¹³¹I]Iodo-Benzyl-Guanidine (^I31I-MIBG) for treatment of iobenguane scan-positive, unresectable, locally advanced or metastatic pheochromocytoma or paraganglioma. With the clinical approval of these novel radiopharmaceuticals for managing select patients with NETs, additional studies are needed to refine patient selection, predict and assess therapy response, and optimize radiopharmaceutical delivery and clinical outcomes.

Occult olfactory neuroblastoma presenting with multiple bone metastases: a case report

RATIONABLE

Olfactory neuroblastoma (ONB) is a rare malignant tumor of the nasal cavity, the primary local symptoms are usually inconspicuous. Patients are often admitted to various specialties based on different primary symptoms, which may result in delayed diagnosis and even a misdiagnosis.

PATIENT CONCERNS

Here we report a case of ONB that presented initially as multiple ostealgia without any local symptoms of the tumor and primarily misdiagnosed as multiple myeloma. The patient was a 47-year-old female with bone pain at multiple sites. The initial diagnosis was considered as multiple myeloma. However, the morphologic examination of bone marrow suggested that the tumor cells originated from the nervous tissues. After the positron emission computed tomography scan, the primary lesion in the nasal cavity was located, and a biopsy was performed.

DIAGNOSIS

The final diagnosis of ONB was confirmed by histopathological tests.

INTERVENTIONS

The patient was treated with metronomic chemotherapy.

OUTCOMES

The symptoms of bone pain were significantly relieved 3 months later. The emission computed tomography scan of the whole body bones and the magnetic resonance imaging of the head showed that the tumor size did not change significantly and proved a progression-free of the disease.

LESSONS

It is a reasonable strategy to identify the original latent tumor by a prompt positron emission computed tomography scan when the primary diagnosis indicates a metastatic disease, especially for the occult malignancies like ONB.

Intralaryngeal paraganglioma workup and discussion of surgical approach

Laryngeal paragangliomas are an uncommon presentation of head and neck paragangliomas, with laryngeal paragangliomas along with a synchronous paraganglioma being exceptionally rare. We present two challenging cases of laryngeal paragangliomas with extralaryngeal extension, completely resected through a transcervical approach without endolaryngeal disruption, with one case having synchronous bilateral carotid body tumours. Both patients had excellent results with complete tumour resection and no resultant functional impact. The surgical approaches for large laryngeal paraganglioma are discussed with considerations for endolaryngeal, transcervical and combined approaches as well as decision-making when approaching these rare lesions in the setting of synchronous head and neck paragangliomas.

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.

Update on Neuroendocrine Carcinomas of the Larynx

OBJECTIVES

Laryngeal neuroendocrine carcinomas are heterogeneous neoplasms characterized by neuroendocrine differentiation. Their prognoses are dependent on tumor type, therefore different classifications have been developed. Moreover, other tumors have overlapping pathologic features posing a range of diagnostic possibilities.

METHODS

A review of the literature was performed to comprehensively understand the classification and diagnosis of these tumors.

RESULTS

We review the past and present classification systems, with emphasis to the latest 2017 World Health Organization Classification of Head and Neck Tumors. We highlight salient clinicopathologic features and discuss the presumptive etiologic role of human papilloma virus. We share a practical algorithmic approach to the diagnosis of suspected neuroendocrine neoplasms of the larynx including a novel marker for neuroendocrine differentiation, insulinoma-associated protein 1.

CONCLUSIONS

Accurate diagnosis and grading of laryngeal neuroendocrine carcinomas is critical for prognostication and therapeutic decision making. The use of an algorithm is instrumental in assuring the exclusion of mimickers.

[A case of paraneoplastic limbic encephalitis associated with neck neuroendocrine carcinoma]

A 69-year-old man presented with a history of personality change for several years. He was admitted to our hospital due to partial seizure. A cerebrospinal fluid test and an electroencephalogram showed no specific abnormalities, but brain magnetic resonance imaging revealed abnormal findings in the right temporal pole, bilateral amygdala to hippocampus, and insular cortex. He was diagnosed with limbic encephalitis accompanied by partial seizure, and received infusion of an antiepileptic agent and acyclovir. Additional examinations for malignancy and autoimmune disease were performed, and neck CT and MRI revealed a neck tumor. Neck lymph node biopsy suggested lymph node metastasis of a neuroendocrine neoplasm derived from other organs. He did not want aggressive treatment involving surgical resection and chemotherapy, and thus, conservative treatment was chosen by an otorhinolaryngologist and immunotherapy was not used. After discharge, the neck tumor grew gradually. To manage the focal mass effect, chemotherapy and surgical resection followed by chemoradiotherapy were performed by the otorhinolaryngologist on days 244 and 325 of the disease course, respectively. Histology of resected tissues disclosed neck neuroendocrine carcinoma derived from a submandibular gland. His personality change improved temporarily after surgical resection, but then worsened again with regrowth of the tumor. He died on day 723. After death, a blood test revealed the presence of anti-amphiphysin antibody. This case suggests that neck neuroendocrine carcinoma can induce paraneoplastic limbic encephalitis, and in such cases, early surgical resection of the neck tumor with suspected lymph node metastasis is necessary both to control symptoms associated with encephalitis and to exclude carcinoma derived from the neck itself.

Well-differentiated Neuroendocrine Carcinoma of the Larynx: Confusion of Terminology and Uncertainty of Early Studies

Well-differentiated neuroendocrine carcinoma (also known as "carcinoid") of the larynx is an exceedingly rare tumor that has an epithelial origin. These tumors are malignant and have a low, but definite, risk of metastasis. Although it can be challenging, this tumor should be differentiated from moderately differentiated neuroendocrine carcinoma (also known as "atypical carcinoid"). The clinical and pathologic features of this tumor, as well as treatment and prognosis, are reviewed in detail.

Primary Sino-nasal Neuroendocrine Carcinoma: A Rare Tumor

Primary sino-nasal neuroendocrine carcinomas (PSNNECs) are rare, with a wide spectrum of histological differentiation. Advanced tumors may invade the surrounding structures, such as the skull base, orbit, or brain. Here, we present a rare case of PSNNEC and its management by concurrent chemoradiation (CCRT) followed by adjuvant chemotherapy with the radiological resolution of the tumor mass.

From Mouth to Brain: Neuroendocrine Markers Play as a Crosstalk Among Oral and Neurodegenerative Diseases

The neuroendocrine system consists of various cells distributed in non-endocrine functional structures, able to synthesize amines and peptides with both local (paracrine) and systemic (endocrine) effects. The presence of such cells, belonging to the neuroendocrine system, is highlighted by the presence of neuroendocrine markers: the most suggestive are chromogranin A, synaptophysin, S-100B protein and glial fibrillary acidic protein. The presence of neuroendocrine markers is commonly associated to the occurrence of neuroendocrine cancers, currently representing the 0.5 percent of all malignant tumors. Nevertheless, neuroendocrine markers have been found to be overexpressed in rare oral neuroendocrine tumors, but also in quite common inflammatory conditions, such as severe periodontitis. The monitoring of neuroendocrine markers is, thus, a common factor of interest among dentistry and neurology: the analysis of neuroendocrine markers in oral diseases may be predictive and prognostic about the severity of neurological diseases, such as lateral amyotrophic sclerosis and traumatic brain injuries. The aim of this mini-review is to highlight the role of neuroendocrine molecules as advantageous diagnostic and prognostic markers for both oral diseases and neurodegenerative disorders.

DNA methylation-based reclassification of olfactory neuroblastoma

Olfactory neuroblastoma/esthesioneuroblastoma (ONB) is an uncommon neuroectodermal neoplasm thought to arise from the olfactory epithelium. Little is known about its molecular pathogenesis. For this study, a retrospective cohort of n = 66 tumor samples with the institutional diagnosis of ONB was analyzed by immunohistochemistry, genome-wide DNA methylation profiling, copy number analysis, and in a subset, next-generation panel sequencing of 560 tumor-associated genes. DNA methylation profiles were compared to those of relevant differential diagnoses of ONB. Unsupervised hierarchical clustering analysis of DNA methylation data revealed four subgroups among institutionally diagnosed ONB. The largest group (n = 42, 64%, Core ONB) presented with classical ONB histology and no overlap with other classes upon methylation profiling-based t-distributed stochastic neighbor embedding (t-SNE) analysis. A second DNA methylation group (n = 7, 11%) with CpG island methylator phenotype (CIMP) consisted of cases with strong expression of cytokeratin, no or scarce chromogranin A expression and IDH2 hotspot mutation in all cases. T-SNE analysis clustered these cases together with sinonasal carcinoma with IDH2 mutation. Four cases (6%) formed a small group characterized by an overall high level of DNA methylation, but without CIMP. The fourth group consisted of 13 cases that had heterogeneous DNA methylation profiles and strong cytokeratin expression in most cases. In t-SNE analysis, these cases mostly grouped among sinonasal adenocarcinoma, squamous cell carcinoma, and undifferentiated carcinoma. Copy number analysis indicated highly recurrent chromosomal changes among Core ONB with a high frequency of combined loss of chromosome 1-4, 8-10, and 12. NGS sequencing did not reveal highly recurrent mutations in ONB, with the only recurrently mutated genes being TP53 and DNMT3A. In conclusion, we demonstrate that institutionally diagnosed ONB are a heterogeneous group of tumors. Expression of cytokeratin, chromogranin A, the mutational status of IDH2 as well as DNA methylation patterns may greatly aid in the precise classification of ONB.

Small Cell Neuroendocrine Carcinoma: A Rare Nasopharyngeal Malignancy with Aggressive Clinical Course

Primary small cell neuroendocrine carcinoma is uncommon in head and neck region, with occasional cases in nasopharynx. Distinction from other round cell tumors is imperative to ensure optimal patient management. We present a case of a 30-year-old woman who presented with a rapidly growing nasopharyngeal mass.

Role of ancillary techniques in profiling unclassified laryngeal malignancies

Laryngeal biopsies, contrary to biopsies from many other sites of the body, very often contain minute amounts of tumour tissue that may consist of morphologically undifferentiated tumour only. In haematoxylin- and eosin-stained sections, there may be no indicative features of what specific tumour entity that is present. In the larynx, particularly small round cell neoplasms, primary or metastatic, often cause a diagnostic dilemma and where an incorrect diagnosis can induce substantial clinical consequences for the patient (e.g., primary neuroendocrine carcinomas vs metastatic variants, certain sarcomas). If sufficient/representative material has been obtained, the application of immunohistochemistry and/or molecular techniques should in virtually every case reveal the true nature of the malignancy. In cases with sparse amount of material, and therefore a limited number of sections to be cut, a careful and thoughtful stepwise approach is necessary to ascertain a reliable diagnosis, or at least guide the clinician to the most likely diagnoses. With today's advanced and widely available technology with an abundance of markers to discriminate different tumours, the use of the term "undifferentiated" should be largely unnecessary. In the exceptional, and indeed exceedingly rare cases, when a classification is not possible, even after repeat biopsy, we suggest that the laryngeal neoplasm is better termed "unclassified malignant neoplasm" rather than "undifferentiated malignant neoplasm".

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.

Neuroendocrine Carcinomas of the Upper Airways: A Small Case Series with Histopathological Considerations

Neuroendocrine carcinomas are rare tumors. In the head and neck region they are most common in the larynx, where they represent 0.5-1% of epithelial cancers. Diagnosis requires the recognition of the typical neuroendocrine architecture and morphology and the immunohistochemical confirmation of neuroendocrine differentiation. In the 1991 WHO classification laryngeal neuroendocrine carcinomas have been divided into carcinoids, atypical carcinoids, small cell carcinomas and paragangliomas. Atypical carcinoids in the head and neck region usually show an aggressive behavior analogous to poorly differentiated carcinomas, and are resistant to chemo- and radiotherapy. For this reason, it was recently proposed to change their designation to “moderately differentiated neuroendocrine carcinomas”.

We present the clinical and histopathological features of 2 moderately differentiated neuroendocrine carcinomas of the larynx, one large cell poorly differentiated neuroendocrine carcinoma of the oropharynx, and one small cell carcinoma of the minor salivary glands of the tongue. The patient with small cell carcinoma was free from disease 26 months after radical surgery, while the other patients showed liver, lung and bone metastases 18, 26 and 24 months after the diagnosis despite radical surgery or concomitant intra-arterial chemotherapy and radiotherapy.

Early Stage olfactory neuroblastoma and the impact of resecting dura and olfactory bulb

OBJECTIVE

Compare outcomes of patients with olfactory neuroblastoma (ONB) without skull base involvement treated with and without resection of the dura and olfactory bulb.

METHODS

Retrospective review of ONB patients treated from 1992 to 2013 at the MD Anderson Cancer Center (The University of Texas, Houston, Texas, U.S.A.). Primary outcomes were overall and disease-free survival.

RESULTS

Thirty-five patients were identified. Most patients had Kadish A/B. tumors (97%), Hyams grade 2 (70%), with unilateral involvement (91%), and arising from the nasal cavity (68%). Tumor involved the mucosa abutting the skull base in 42% of patients. Twenty-five patients (71%) received surgery and radiation, whereas the remainder had surgery alone. Five patients (14%) had bony skull base resection, and eight patients (23%) had resection of bony skull base, dura, and olfactory bulb. Surgical margins were grossly positive in one patient (3%) and microscopically positive in four patients (12%). The 5- and 10-year overall survival were 93% and 81%, respectively. The 5- and 10-year disease-free survival (DFS) were 89% and 78%, respectively. Bony cribriform plate resection was associated with better DFS (P = 0.05), but dura and olfactory bulb resection was not (P = 0.11). There was a trend toward improved DFS in patients with negative resection margins (P = 0.19). Surgical modality (open vs. endoscopic) and postoperative radiotherapy did not impact DFS.

CONCLUSION

Most Kadish A/B ONB tumors have low Hyams grade, unilateral involvement, and favorable survival outcomes. Resection of the dura and olfactory bulb is not oncologically advantageous in patients without skull base involvement who are surgically treated with negative resection margins and cribriform resection.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:1274-1280, 2018.

Sinonasal Tract Alveolar Rhabdomyosarcoma in Adults: A Clinicopathologic and Immunophenotypic Study of Fifty-Two Cases with Emphasis on Epithelial Immunoreactivity

Sinonasal tract (SNT) alveolar rhabdomyosarcoma (ARMS) are frequently misdiagnosed, especially in adults. Fifty-two adult (≥18 years) patients with SNT ARMS were reviewed and characterized by immunohistochemistry and molecular studies. Twenty-six females and 26 males (18-72 years; mean 43.2 years), presented after a short duration (mean 2.6 months) with a large (mean 5.5 cm) destructive nasal cavity mass, involving multiple contiguous paranasal sites (n = 46) and with cervical adenopathy (n = 41). The tumors showed an alveolar, nested to solid growth pattern below an intact, but often involved (n = 9) epithelium with frequent necrosis (n = 37), destructive bone invasion (n = 30), and lymphovascular invasion (n = 25). The neoplastic cells were dyshesive and dilapidated, with crush artifacts. Rhabdoid features (n = 36) and tumor cell multinucleation (n = 28) were common. Mitotic counts were high (mean 17/10 HPFs). The neoplastic cells showed the following immunohistochemical positive findings: desmin (100%), myogenin (100%), MYOD1 (100%), MSA (96%), SMA (52%), CAM5.2 (50%), AE1/AE3 (36%); other positive markers included S100 protein (27%), CD56 (100%), synaptophysin (35%), and chromogranin (13%). Overall, 54% show epithelial marker reactivity. Molecular studies showed FOXO1 translocations (81%) with PCR demonstrating PAX3 in 72.7% tested. Patients presented with high stage (IV 24; III 26) and metastatic disease (lymph nodes n = 41; distant metastases n = 25) (IRSG grouping). Surgery (n = 16), radiation (n = 41) and chemotherapy (n = 45) yielded an overall survival of 36.1 months (mean; range 2.4-286); 18 alive without disease (mean 69.6 months); 7 alive with disease (mean 11.0 months); 1 dead without disease (63.7 months); and 26 dead with disease (mean 18.5 months). SNT ARMS frequently present in adults as a large, destructive midline mass of short symptom duration, with high stage disease. The alveolar to solid pattern of growth of cells with rhabdoid-plasmacytoid features suggests the diagnosis, but epithelial immunohistochemistry markers are present in 54% of cases, leading to misdiagnosis as carcinomas if muscle markers are not also performed. Overall survival of 36.1 months is achieved with multimodality therapy, but 64% have incurable disease (16.9 months). Mixed anatomic site (p = 0.02) was a significant adverse prognostic indicator, while stage (0.06) and tumor size >5 cm (0.06) approached marginal significance.

Pathologic Progression, Possible Origin, and Management of Multiple Primary Intracranial Neuroendocrine Carcinomas

BACKGROUND

Primary intracranial neuroendocrine carcinomas (NECs) are extremely rare malignant tumors with no previous reports of multiple ones in the literatures.

CASE DESCRIPTION

The clinical presentation, preoperative and reexamined magnetic resonance imaging findings, as well as histopathologic studies of a 56-year-old female subject with multiple intracranial NECs mimicking multiple intracranial meningiomas, who underwent 3 operations with left parietal craniotomy, right occipital parietal craniotomy, and left frontal craniotomy, separately and chronologically, are presented in this article. Noteworthy, the first and second tumors were confirmed as NECs exhibiting histologic characteristics of typical anaplastic meningiomas with features of whorl formation, while the third tumor was a typical NEC with features of organoid cancer nests. In other words, the first 2 lesions were diagnosed as meningioma as opposed to NEC. It was only after the third surgery that the pathology for the first 2 cases was reviewed and had a revised diagnosis. After the third surgical resection, the patient further received whole brain radiotherapy and systemic chemotherapy (temozolomide combined with YH-16). At her 10-month follow-up, the patient achieved a good outcome.

CONCLUSIONS

Multiple primary intracranial NECs are extremely rare. The tumor might be of arachnoidal or leptomeningeal origin, with histologic patterns that might lead to transformation and/or progression. Maximal surgical resection is warranted for symptomatic mass effect. Postoperative adjuvant treatments including radiotherapy and chemotherapy should be a recommended therapeutic modality.

Squamous cell carcinoma arising within a maxillary odontogenic keratocyst: A rare occurrence

Squamous cell carcinoma (SCC) arising within the lining of an odontogenic keratocyst (OKC) is a rare occurrence. Although potentially locally destructive, OKC is a benign odontogenic process that typically presents with clinical and radiographic features characteristic of a benign intraosseous neoplasm. We present the clinical and radiographic features of a maxillary mass that demonstrated SCC arising from the lining of an OKC. Although the initial clinical and radiographic presentation suggested an infection or malignant neoplasm, biopsies revealed an infiltrative well-differentiated SCC contiguous with and arising from the focus of a pre-existing OKC. The patient subsequently underwent a type II hemi-maxillectomy with neoadjuvant chemoradiation. This report discusses the clinical and radiographic features associated with intraosseous malignancies, especially those arising from an otherwise benign odontogenic lesion. While the majority of OKCs are benign, the current report illustrates the potential for carcinomatous transformation within the lining of an OKC.

Differential Diagnosis in Neuroendocrine Neoplasms of the Larynx

The differential diagnosis of neuroendocrine neoplasms of the larynx is broad and includes lesions of epithelial, mesenchymal, and neuroectodermal origin. These lesions have overlapping clinical and pathologic aspects and must be carefully considered in the differential diagnosis of laryngeal neoplasms. The prognosis and treatment are also different among these tumor types, which necessitates making these distinctions clinically. The current literature was reviewed to provide updated information regarding the epithelial-derived tumors, including carcinoid, atypical carcinoid, small cell neuroendocrine carcinomas, large cell neuroendocrine carcinoma, and squamous cell carcinoma with neuroendocrine component. These tumors are compared and contrasted with non-epithelial-derived tumors such as paraganglioma and nonmucosal tumors, such as medullary thyroid carcinoma. The morphologic and cytologic features are discussed, along with helpful immunohistochemical and ancillary investigations.

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 Carcinomas with Neuroendocrine Features: Histopathological Differentiation and Treatment Outcomes

Objectives Sinonasal cancers with neuroendocrine features share similar clinical, radiological, and histopathological features; however, these tumors often exhibit varying degrees of aggressive behavior presenting significant treatment challenges. The objective of this study was to report our experience with these rare malignancies and to present a review of current literature. Methods Following institutional review board approval, the records of all patients with biopsy-proven sinonasal malignancies over a 5-year period were reviewed. Results The study included 14 patients with olfactory neuroblastomas (ONBs), 7 patients with sinonasal undifferentiated carcinomas (SNUC), and 2 patients with sinonasal neuroendocrine carcinomas (SNEC). Histopathologic markers aided in final diagnosis, but showed variable specificity. In patients with sufficient follow-up, the 2-year disease-free survival rate was 81% (9/11) for ONB and 75% (3/4) for SNUC. Three patients developed a regional or distant recurrence (two with ONBs and one with SNUC). Two patients, one with SNEC and one with ONB, succumbed to brain radionecrosis related to proton radiation therapy. Conclusions Overlapping clinical and histopathological features in poorly differentiated sinonasal cancers with neuroendocrine features continue to present a diagnostic challenge. Individualized assessment and treatment strategies can improve the accuracy of the initial assessment and the treatment outcomes.

Meta-analysis of 701 published cases of sinonasal neuroendocrine carcinoma: The importance of differentiation grade in determining treatment strategy

The aim of this meta-analysis was to provide treatment guidelines for sinonasal neuroendocrine carcinoma (SNC) by combining all available data in the literature. A literature search for all studies concerning SNC was performed against the MEDLINE and EMBASE databases. Available clinical data was normalized, pooled, and statistically analyzed. A total of 701 cases of SNC were available for analysis, comprising 127 well or moderately differentiated sinonasal neuroendocrine carcinomas (SNEC), 459 sinonasal undifferentiated carcinoma (SNUC) and 115 sinonasal small cell carcinoma (SmCC). Tumor type was the most important predictor of survival, with a 5-year disease-specific survival (DSS) of 70.2% for SNEC, 35.9% for SNUC and 46.1% for SmCC. Tumor stage on presentation was of limited value in predicting survival or response to treatment. Overall, the application of surgery yielded significantly better results (5-year DSS 52.2% versus 30.1%, p<0.001). In SNUC, radiotherapy was a beneficial supplement to surgery (5-year DSS 54.7% versus 15.7%, p=0.027), while radiotherapy as monotherapy performed poorly (5-year DSS 17.9%). Chemotherapy did not appear to contribute to survival. Based on these findings, we can conclude that the most important predictors of survival in SNC are differentiation grade and the associated choice of treatment modality. In contrast to other head and neck cancers, tumor staging appears of limited value in predicting survival or deciding on a treatment strategy. Surgery should be the cornerstone of treatment, supplemented by radiotherapy in poorly differentiated subtypes (SNUC, SmCC). Chemotherapy does not appear to contribute to survival.

Human papillomavirus-associated small cell carcinoma/neuroendocrine carcinoma of the oropharynx: a report of two cases

Introduction

Small cell carcinoma/neuroendocrine carcinoma (SCNEC) of the oropharynx is uncommon. Two cases of SCNEC in an 81-year-old woman and in a 54-year-old man are presented here.

Case description

We have documented two cases of SCNEC arising in the oropharynx with evidence of high-risk human papillomavirus (HPV) infection. Histologically, both cases were classified as poorly differentiated SCNEC with high nuclear-to-cytoplasmic ratios and nuclear molding. Observations using a transmission electron microscope revealed membrane-bound neuroendocrine granules in some tumor cells. Both tumors expressed high levels of p16, a surrogate marker for high-risk HPV infection. HPV infection was confirmed in both cases using HPV polymerase chain reaction analysis; HPV subtype 16 was identified in one case and HPV subtype 18 in the other.

Discussion and Evaluation

SCNEC of the oropharynx is a rare and novel HPV-associated disease with neuroendocrine granules and aggressive clinical behavior.

Conclusions

Herein, we present two cases of SCNEC, focusing on its histologic features and treatment modalities. More studies are required to elucidate the pathophysiology of HPV-associated SCNEC in different organ systems.

Electronic supplementary material

The online version of this article (doi:10.1186/s40064-016-3501-x) contains supplementary material, which is available to authorized users.

A Rare Primary Neuroendocrine Tumor (Typical Carcinoid) of the Sublingual Gland

A typical carcinoid is extremely rare in the oral cavity. We here present a case of a typical carcinoid arising in the sublingual gland of a 62-year-old woman. The tumor was removed by primary excision with 10 mm surgical margins and submandibular dissection. Examination of the tumor showed medium-sized tumor cells that were positive for CD56 and chromogranin A, with no necrosis, and with a mitotic count less than 1/10 HPF. A pathological diagnosis of typical carcinoid was made from both morphological and immunological examinations. One year after excision surgery, there was no tumor recurrence or neck metastasis.