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

Hiding in plain sight: NUT carcinoma is an unrecognized subtype of squamous cell carcinoma of the lungs and head and neck

In the past two decades, treatment for non-small-cell lung cancers (NSCLCs) and head and neck squamous cell carcinoma (HNSCC) has advanced considerably, owing largely to the characterization of distinct oncological subtypes, the development of targeted therapies for each subtype and the advent of immunotherapy. Data emerging over the past two decades suggest that NUT carcinoma, a highly aggressive malignancy driven by a NUT fusion oncoprotein and arising in the lungs, head and neck, and rarely in other sites, is a squamous cell carcinoma (SCC) based on transcriptional, histopathological, cell-of-origin and molecular characteristics. NUT carcinoma has an estimated incidence of 1,400 cases per year in the United States, surpassing that of some rare NSCLC and HNSCC subtypes. However, NUT carcinoma is currently not recognized as an SCC of the lungs or head and neck. The orphan classification of NUT carcinoma as a distinct entity leads to a lack of awareness of this malignancy among oncologists and surgeons, despite early diagnosis being crucial for this cancer type with a median survival of only ~6.5 months. Consequently, NUT carcinoma is underdiagnosed and often misdiagnosed, resulting in limited research and progress in developing effective treatments in one of the most aggressive forms of lung and head and neck cancer. With a growing number of targeted agents that can potentially be used to treat NUT carcinoma, improved recognition through reclassification and inclusion of NUT carcinoma as a squamous NSCLC or an HNSCC when arising in these locations will accelerate the development of effective therapies for this disease. Thus, in the Perspective, we propose such a reclassification of NUT carcinoma as an SCC and discuss the supporting evidence.

M&M: an RNA-seq based pan-cancer classifier for paediatric tumours

BACKGROUND

With many rare tumour types, acquiring the correct diagnosis is a challenging but crucial process in paediatric oncology. Historically, this is done based on histology and morphology of the disease. However, advances in genome wide profiling techniques such as RNA sequencing now allow the development of molecular classification tools.

METHODS

Here, we present M&M, a pan-paediatric cancer ensemble-based machine learning algorithm tailored towards inclusion of rare tumour types.

FINDINGS

The RNA-seq based algorithm can classify 52 different tumour types (precision ∼99%, recall ∼80%), plus the underlying 96 tumour subtypes (precision ∼96%, recall ∼70%). For low-confidence classifications, a comparable precision is achieved when including the three highest-scoring labels. We then validated M&M on an internal dataset (precision 99%, recall 76%) and an external dataset from the KidsFirst initiative (precision 98%, recall 77%). Finally, we show that M&M has similar performance as existing disease or domain specific classification algorithms based on RNA sequencing or methylation data.

INTERPRETATION

M&M's pan-cancer setup allows for easy clinical implementation, requiring only one classifier for all incoming diagnostic samples, including samples from different tumour stages and treatment statuses. Simultaneously, its performance is comparable to existing tumour- and tissue-specific classifiers. The introduction of an extensive pan-cancer classifier in diagnostics has the potential to increase diagnostic accuracy for many paediatric cancer cases, thereby contributing towards optimal patient survival and quality of life.

FUNDING

Financial support was provided by the Foundation Children Cancer Free (KiKa core funding) and Adessium Foundation.

Olfaction Preservation and Long-Term Outcomes in Patients with Unilateral Endoscopic Resection of Olfactory Neuroblastoma: A Systematic Review and Institutional Experience

BACKGROUND

Endoscopic endonasal surgical resection is an effective therapeutic approach for olfactory neuroblastoma (ONB). Unilateral excision of ONBs with limited extension has been reported with the purpose of preserving olfactory function. We aimed to review implications of surgical management, olfactory preservation feasibility, and survival outcomes in patients who underwent endoscopic unilateral resection of ONB.

METHODS

A systematic literature review was conducted using the search terms [("Olfactory neuroblastoma") OR ("Esthesioneuroblastoma")] AND [("Unilateral resection") OR ("Olfaction preservation")]. Studies reporting cases of unilateral ONB endoscopic resection with postoperative olfaction assessment were included. Concurrently, records of patients who met inclusion criteria at our institution were reviewed retrospectively. The survival and olfactory outcomes were analyzed in both cohorts.

RESULTS

Thirty-three patients were identified in the published literature. Twenty-three (69.7%) reported postoperative olfaction preservation. Olfactory function after surgery did not show an association with Kadish stage (P = 0.128). No evidence of disease was observed at the latest follow-up in this group of patients. Nine patients who met inclusion criteria were identified at our institution. The extent of resection influenced the level of olfaction preservation when cribriform plate and nasal septum resection coexisted (P = 0.05). A single patient at our institution developed recurrence after being lost to follow-up for 22 months.

CONCLUSIONS

Olfaction preservation can be achieved in patients who undergo endoscopic unilateral resection and adjuvant radiotherapy. The extent of resection should aim for negative margins, particularly in the midline. Larger studies are required to assess the risk of contralateral microscopic disease, and, hence, close follow-up is advised.

Amelanotic Melanoma: A Rare Sinonasal Malignancy

Mucosal melanomas account for less than 1% of all sinonasal malignancies and are aggressive tumours originating from melanocytes in various mucosal epithelia. Diagnosis is often delayed due to nonspecific symptoms, contributing to challenges in treatment and management. We present a case of a 75-year-old female with epistaxis and nasal blockage, ultimately diagnosed with amelanotic sinonasal melanoma. Despite diagnostic difficulties exacerbated by profuse bleeding during biopsy attempts, a comprehensive approach involving clinical evaluation, imaging, and histopathology led to a definitive diagnosis. Immunohistochemistry played a crucial role in confirming the diagnosis, ruling out differential diagnoses such as olfactory neuroblastoma and lymphoma. Surgical excision, despite intraoperative bleeding, was successful, followed by adjuvant chemotherapy and radiotherapy due to the tumor's advanced stage. The case underscores the importance of a multidisciplinary approach and personalized treatment strategies, considering the tumor's molecular characteristics for improved outcomes in managing this rare malignancy.

Blastic Plasmacytoid Dendritic Cell Neoplasm, from a Dermatological Point of View

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an aggressive hematological malignancy derived from the precursors of plasmacytoid dendritic cells. Although disease awareness has increased over time, BPDCN represents a rare disease with an aggressive clinical course and a dismal prognosis. Due to the overlap in clinical and histological features with a large spectrum of inflammatory and neoplastic diseases, BPDCN is difficult to diagnose. Furthermore, given the rarity of the disease, treatment options for BPDCN are limited, sometimes changing by practitioner and hospitals. Treatment options range from conventional chemotherapy to the recently approved biologic agent tagraxofusp and stem cell transplantation. Therefore, a multidisciplinary approach with coordination among dermatologists, pathologists, and hematologists is ultimately imperative to reach the correct diagnosis and management of BPDCN.

Primary Small Cell Carcinoma in Nasal Cavity and Paranasal Sinuses: 15 Cases From a Single Center

Small cell carcinoma (SCC) in the nasal cavity and sinuses is extremely rare. The clinical data of 15 patients with primary SCC in nasal cavity and sinuses were analyzed retrospectively. All patients were treated with surgery, radiotherapy, and chemotherapy. Of the 15 patients, 2 patients are alive for more than 6 years, and 5 patients died after the median follow-up period (11 months). Most of our patients represent the later stage (73% presented at stage III or IV) and had surgery combined with radiotherapy and chemotherapy; however, nearly half of patients have tumor recurrence and/or distant metastasis. SCC of nasal cavity and sinuses often invades surrounding tissues, and the long-term curative rate is generally low. Early diagnosis and comprehensive treatment are key to improve survival. Although the overall survival time of SCC is not optimistic, it is still recommended that patients take comprehensive treatment.

Extraskeletal Mesenchymal Chondrosarcoma in Nasal Cavity: A Rare Case Report

Extraskeletal mesenchymal chondrosarcoma (ESMC) originate from the nasal cavity have rarely been reported, especially its imaging features, which makes the preoperative diagnosis difficult. Here, we report the clinical, computed tomography, and magnetic resonance imaging features of a 60-year-old female patient with pathologically confirmed ESMC in the nasal cavity to help provide more reference for diagnosis before operation. Extraskeletal mesenchymal chondrosarcoma in the nasal cavity demonstrates typical imaging features, such as mesh-like enhancement, calcification, hemorrhage, necrosis, cystic degeneration, and so on.

Expression of NKX2.2 in Non-Ewing Tumors With Round Cell Morphology

Background Round cell sarcomas pose diagnostic challenges due to overlapping histopathological features, necessitating precise immunohistochemical markers for accurate categorization. NKX2.2 has emerged as a sensitive diagnostic tool, particularly in Ewing sarcoma. This study extends this understanding to various round-cell sarcomas, shedding light on the potential diagnostic utility of NKX2.2 beyond its established role. The nuanced exploration of NKX2.2 expression aims to enhance diagnostic strategies, prognostic assessments, and therapeutic developments in the landscape of sarcoma research. Methodology Cases were retrieved from the surgical pathology and consultation files of Shaukat Khanum Memorial Cancer Hospital and Research Center, Lahore, Pakistan. Representative hematoxylin and eosin-stained slides of six different types of already confirmed tumors, including lymphoblastic lymphoma, neuroblastoma, rhabdomyosarcoma, synovial sarcoma, Wilms tumor, and Ewing sarcoma, were reviewed by a panel of pathologists. Immunohistochemistry, utilizing a rabbit anti-NKX2.2 monoclonal antibody, was performed on formalin-fixed paraffin-embedded tissue sections. The presence of NKX2.2 was defined as moderate or high nuclear immunoreactivity in at least 5% of cells. Results The histopathological examination revealed characteristic features in each sarcoma subtype, aligning with established diagnostic criteria. In Lymphoblastic lymphoma, T-cell lineage was confirmed through TdT expression, while the atypical finding of focal NKX 2.2 expression hinted at genetic diversity. Neuroblastoma exhibited the expected salt and pepper chromatin pattern, with NKX 2.2 expression raising questions about its prognostic significance. Rhabdomyosarcoma presented primitive cells expressing desmin, and NKX 2.2 focal expression echoed previous subtype-associated studies. Synovial sarcoma displayed both monophasic and biphasic growth patterns and TLE1 expression, with NKX 2.2 variation suggesting tumor heterogeneity. In Wilms tumor, the characteristic WT1 expression was observed, while NKX2.2's absence reaffirmed its irrelevance in this context. Ewing sarcoma displayed the anticipated homogenous cell population, strong NKX2.2 expression, and CD99 positivity across various sites. Furthermore, age and gender impact on this range of sarcomas found no significant relation with an expression of NKX2.2. Conclusion In conclusion, the diverse expression profiles of diagnostic markers discovered in this study, particularly the atypical expression of NKX2.2 beyond its established role in Ewing sarcoma, signify a significant advancement. This unique finding accentuates the potential diagnostic importance of NKX2.2 in various sarcomas, presenting a novel dimension to our understanding of these malignancies.

Small Round Blue Cell Tumours of the Sinonasal Area: Our 5 year Experience in a Tertiary Care Centre in India

Purpose: The main purpose of this study is to understand the characteristics and management of sinonasal small round blue cell tumors and also to emphasise the role of immunohistochemistry in their diagnosis and on the outcomes after endoscopic/open excision in these patients. Methods: This is a retrospective study conducted at a tertiary care referral centre in India which included 38 patients with sino nasal for a period of 5 years. All the patients were evaluated clinically and radiologically. All cases were confirmed diagnostically with histopathological examination and immunohistochemistry following surgical excision either by endoscopic or open approach. Some of the cases underwent post operative radiotherapy. Results: In our study, among 176 cases diagnosed with Sino nasal malignancies, 38 (21.6%) cases were diagnosed with sinonasal small round blue cell tumors with male to female ratio 1.4:1. Most common histopathological type among all the sinonasal small round blue cell tumors that presented to us was esthesioneuroblastoma i.e., 8 (21%) patients followed by pituitary macroadenoma in 7(8.4%) patients. Other types are undifferentiated squamous cell carcinoma 10(13.1%), craniopharyngioma 8(10.5%), lymphoma 3(7.9%), synovial/spindle cell sarcoma, malignant melanoma and adenocarcinoma 1(2.6%) each. Schwannoma, rhabdomyosarcoma, neuroendocrine carcinoma and neurofibroma 2 (5.2%) each. Conclusion: Sinonasal small round blue cell tumors are extremely rare tumours. Histopathological diagnosis with immunohistochemistry is characteristic of various tumors and is conclusive for diagnosis. Knowledge of these tumor entity is essential as early diagnosis helps in further management in preventing spread to vital structures and improving outcome. Most of the tumors have a multimodality treatment approach which includes surgical excision, radiotherapy and chemotherapy.

PET/CT Imaging in Treatment Planning and Surveillance of Sinonasal Neoplasms

Sinonasal cancers are uncommon malignancies with a generally unfavorable prognosis, often presenting at an advanced stage. Their high rate of recurrence supports close imaging surveillance and the utilization of functional imaging techniques. Whole-body 18F-FDG PET/CT has very high sensitivity for the diagnosis of sinonasal malignancies and can also be used as a "metabolic biopsy" in the characterization of some of the more common subgroups of these tumors, though due to overlap in uptake, histological confirmation is still needed. For certain tumor types, radiotracers, such as 11C-choline, and radiolabeled somatostatin analogs, including 68Ga-DOTATATE/DOTATOC, have proven useful in treatment planning and surveillance. Although serial scans for posttreatment surveillance allow the detection of subclinical lesions, the optimal schedule and efficacy in terms of survival are yet to be determined. Pitfalls of 18F-FDG, such as post-surgical and post-radiotherapy crusting and inflammation, may cause false-positive hypermetabolism in the absence of relapse.

Nasal Malignant Melanoma With an Inverted Papilloma in the Contralateral Nasal Cavity: A Case Report

Background: We describe a patient with sinonasal mucosal melanoma (SNMM) and an inverted papilloma, which existed independently in both nasal cavities. Case presentation: We describe an unusual case of a 74-year-old male patient with SNMM and an inverted papilloma. He presented with symptoms of coughing up blood and pain in the left forehead. The patient underwent surgical resection of the lesion, and the SNMM and inverted papilloma were confirmed by histopathology. The patient refused further treatment after surgery, but was re-admitted 7 months later with local recurrence of the left tumor and systemic metastases. Conclusions: Nasal malignant melanoma with an inverted papilloma in the contralateral nasal cavity is rare and can easily be misdiagnosed as the same tumor by imaging. Simultaneous histopathology of bilateral nasal masses is very necessary. The recommended treatment is surgery for the inverted papilloma. An SNMM is a devastating tumor with poor outcomes.

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.

Cutaneous Metastasis of Alveolar Rhabdomyosarcoma in a Child

ABSTRACT

Rhabdomyosarcoma (RMS) is one of the most common soft tissue sarcomas in children. This lesion is classically included in the generic group of "small round blue cell tumors" along with other entities that share similar microscopic features. Although the head and neck region is a frequent site for primary tumors, cutaneous metastases of RMS involving this anatomical location are rare in the pediatric population. We report a case of a 12-year old girl previously diagnosed with a primary alveolar RMS involving the left maxillary sinus, presenting with a metastatic lesion on the skin of the left temple area. Along with a brief review of the previous case reports on the topic, we highlight the initial immunohistochemistry panel useful for diagnosing this tumor.

Extraskeletal Ewing sarcoma of the stomach: A rare case report

BACKGROUND

Extraskeletal Ewing sarcoma (EES) is a rare and highly malignant small round cell tumor associated with a poor clinical outcome. Ewing sarcoma (ES) involving the stomach is an uncommon presentation and can be easily confused with other small round cell tumors. We herein present a rare case of ES involving the gastric area.

CASE SUMMARY

We report a case of gastric ES in a 19-year-old female patient who initially presented with a complaint of a tender epigastric mass for 5 d. Contrast-enhanced abdominal computed tomography revealed a soft-tissue-density mass with a diameter of 8.5 cm between the liver and stomach; the mass was connected to the gastric antrum. Then, the mass was surgically excised completely. Upon histopathological, immunophenotype and molecular analysis, the mass was identified to be a primary gastric ES.

CONCLUSION

EES is an aggressive tumor with poor prognosis. Therefore, early diagnosis and timely intervention are essential for a good prognosis. It is imperative for us to raise awareness about this rare tumor. Surgical resection is still the best treatment option.

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.

Merkel Cell Carcinoma: An Otolaryngological Point of View of An Unusual Sinonasal Mass

Merkel cell carcinoma is a pathologic diagnosis mainly observed in sun-exposed cutaneous areas, like the head and neck. Ultraviolet (UV) exposure and immunosuppression are the common predisposing factors. Merkel cell carcinoma of the head and neck is quite an uncommon disease. This case report involves a 56-year-old man who exhibited a skin lesion on the nasal dorsum with a mass in the right maxillary sinus. The biopsies from both sides were diagnostic for Merkel cell carcinoma. The patient underwent endoscopic sinus surgery and removal of the skin lesion with free margins. The patient has been free of disease for the last 20 months now and maintains follow-up with endoscopy and imaging in the Ear Nose Throat office. Only a few cases of Merkel cell carcinoma of the nasal mucosa have been reported in the literature. We report our approach and management of this rare pathologic presentation.

Desmoplastic Small Round Cell Tumor of the Head and Neck: A Potential Diagnostic Pitfall

Primary desmoplastic small round cell tumor (DSRCT) in the head and neck region is extremely rare. There is limited information about its clinicopathological characteristics, prognosis, and treatment modalities. The purpose of this study is to provide a comprehensive review of DSRCT occurring primarily in the head and neck, to demonstrate its peculiar morphology and immunohistochemical expression, and to address the differential diagnoses. A total of 25 cases were collected after a thorough review of the relevant literature. DSRCT was most frequently reported in the major salivary glands, followed by the eyes. Furthermore, some cases were misinterpreted as poorly differentiated carcinoma, Ewing sarcoma, and olfactory neuroblastoma. Diagnosing DSRCTs in the head and neck can be very challenging due to their rarity in this location, overlapping morphology, and immunohistochemistry. In these cases, following a systemic approach helps to solve diagnostic problems.

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.

Adult Patient With Neuroblastoma Presenting as Acute Leukemia

Neuroblastoma (NB) is the most common extra-cranial cancer of early childhood and rarely occurs in adults. The clinical symptoms of NB can be diverse. We discuss a rare case of an adult NB presenting as acute leukemia. A 45-year-old woman presented with persistent hip pain, weight loss, anemia, and incidental fever for several months. Imaging studies showed diffuse bone marrow (BM) uptake and hypermetabolic lesions involving the left adrenal gland, bilateral axillary nodes, and left lateral aspect of the abdomen. Her 24-hour urine catecholamines were within the normal range. On the peripheral blood film, blast-like cells were noted, occupying approximately 2% of leukocytes. The BM imprints showed infiltration of blast-like cells with convoluted nuclei and scant cytoplasm in more than 85% of the total nucleated cells. Acute leukemia was initially suspected based on morphology. Blast-like cells were negative for myeloperoxidase, combined esterase, periodic acid-Schiff, CD45RB, CD68, and CD138. In a further study, these cells were positive for CD56, synaptophysin (SYN), and CD99 with negativity for desmin, myogenin, NKX-2.2, CD31, cytokeratin (AE1/AE3), Melan-A, ERG, S-100, and SALL4. Morphologically similar neoplastic cells in axillary node biopsy were positive for CD56, chromogranin A, SYN, and neurofilament, but negative for GFAP, CD246, and vimentin. Based on laboratory, pathological, and imaging studies, metastatic NB with BM and multifocal involvement was diagnosed. The differential diagnosis of metastatic small blue round cell tumors should be considered for adult patients with circulating blast-like cells, and an accurate diagnosis would enable the patient to receive appropriate and timely treatment.

Update from the 5th Edition of the World Health Organization Classification of Head and Neck Tumors: Hypopharynx, Larynx, Trachea and Parapharyngeal Space

In this article, we review the chapter on tumors of the larynx, hypopharynx, trachea and parapharyngeal space in the new edition of the WHO book, focusing on the new developments in comparison to the previous edition. Squamous cell carcinoma (SCC) and its variants are by far the most common malignancies at these locations, with very limited new insights. The most important is the introduction of new targeted treatment-checkpoint inhibitors, with a new task for pathologists, who may help to predict the response to treatment by analyzing the expression of targeted proteins in biopsy samples. Precancerous lesions remain a controversial topic and, similarly to other organs, it is acceptable to use the terms "dysplasia" or "squamous intraepithelial lesion" (SIL), but there is a slight difference between low-grade dysplasia and low-grade SIL: in the former, mild atypia must be present, while the latter also includes hyperplastic epithelium without atypia. Two approaches have been proposed: a two-tiered system with low- and high-grade dysplasia/SIL and a three-tiered system with an additional category, carcinoma in situ. We are still searching for reliable diagnostic markers to surpass the subjectivity in biopsy diagnosis, with a few potential candidate markers on the horizon, e.g., stem cell markers. Other tumors are rare at these locations, e.g., hematolymphoid, neuroendocrine and salivary gland neoplasms, and are no longer included in Chapter 3. They must be diagnosed according to criteria described in specific chapters. The same holds true for soft tissue tumors, with the exception of cartilaginous neoplasms, which are still included in Chapter 3.

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

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

Molecular Biomarkers in Sinonasal Cancers: New Frontiers in Diagnosis and Treatment

Purpose of Review

Sinonasal tumors are rare and heterogeneous diseases which pose challenges in diagnosis and treatment. Despite significant progress made in surgical, oncological, and radiotherapy fields, their prognosis still remains poor. Therefore, alternative strategies should be studied in order to refine diagnosis and improve patient care.

Recent Findings

In recent years, in-depth molecular studies have identified new biological markers, such as genetic abnormalities and epigenetic variations, which have allowed to refine diagnosis and predict prognosis. As a consequence, new histological entities have been described and specific subgroup stratifications within the well-known histotypes have been made possible. These discoveries have expanded indications for immunotherapy and targeted therapies in order to reduce tumor spread, thus representing a valuable implementation of standard treatments.

Summary

Recent findings in molecular biology have paved the way for better understanding and managing such rare and aggressive tumors. Although further efforts need to be made in this direction, expectations are promising.

Machine learning to differentiate small round cell malignant tumors and non-small round cell malignant tumors of the nasal and paranasal sinuses using apparent diffusion coefficient values

OBJECTIVE

We used radiomics feature-based machine learning classifiers of apparent diffusion coefficient (ADC) maps to differentiate small round cell malignant tumors (SRCMTs) and non-SRCMTs of the nasal and paranasal sinuses.

MATERIALS

A total of 267 features were extracted from each region of interest (ROI). Datasets were randomized into two sets, a training set (∼70%) and a test set (∼30%). We performed dimensional reductions using the Pearson correlation coefficient and feature selection analyses (analysis of variance [ANOVA], relief, recursive feature elimination [RFE]) and classifications using 10 machine learning classifiers. Results were evaluated with a leave-one-out cross-validation analysis.

RESULTS

We compared the AUC for all the pipelines in the validation dataset using FeAture Explorer (FAE) software. The pipeline using RFE feature selection and Gaussian process classifier yielded the highest AUCs with ten features. When the "one-standard error" rule was used, FAE produced a simpler model with eight features, including Perc.01%, Perc.10%, Perc.90%, Perc.99%, S(1,0) SumAverg, S(5,5) AngScMom, S(5,5) Correlat, and WavEnLH_s-2. The AUCs of the training, validation, and test datasets achieved 0.995, 0.902, and 0.710, respectively. For ANOVA, the pipeline with the auto-encoder classifier yielded the highest AUC using only one feature, Perc.10% (training/validation/test datasets: 0.886/0.895/0.809, respectively). For the relief, the AUCs of the training, validation, and test datasets that used the LRLasso classifier using five features (Perc.01%, Perc.10%, S(4,4) Correlat, S(5,0) SumAverg, S(5,0) Contrast) were 0.892, 0.886, and 0.787, respectively. Compared with the RFE and relief, the results of all algorithms of ANOVA feature selection were more stable with the AUC values higher than 0.800.

CONCLUSIONS

We demonstrated the feasibility of combining artificial intelligence with the radiomics from ADC values in the differential diagnosis of SRCMTs and non-SRCMTs and the potential of this non-invasive approach for clinical applications.

KEY POINTS

• The parameter with the best diagnostic performance in differentiating SRCMTs from non-SRCMTs was the Perc.10% ADC value. • Results of all the algorithms of ANOVA feature selection were more stable and the AUCs were higher than 0.800, as compared with RFE and relief. • The pipeline using RFE feature selection and Gaussian process classifier yielded the highest AUC.

Texture Analysis of Fat-Suppressed T2-Weighted Magnetic Resonance Imaging and Use of Machine Learning to Discriminate Nasal and Paranasal Sinus Small Round Malignant Cell Tumors

Objective

We used texture analysis and machine learning (ML) to classify small round cell malignant tumors (SRCMTs) and Non-SRCMTs of nasal and paranasal sinus on fat-suppressed T2 weighted imaging (Fs-T2WI).

Materials

Preoperative MRI scans of 164 patients from 1 January 2018 to 1 January 2021 diagnosed with SRCMTs and Non-SRCMTs were included in this study. A total of 271 features were extracted from each regions of interest. Datasets were randomly divided into two sets, including a training set (∼70%) and a test set (∼30%). The Pearson correlation coefficient (PCC) and principal component analysis (PCA) methods were performed to reduce dimensions, and the Analysis of Variance (ANOVA), Kruskal-Wallis (KW), and Recursive Feature Elimination (RFE) and Relief were performed for feature selections. Classifications were performed using 10 ML classifiers. Results were evaluated using a leave one out cross-validation analysis.

Results

We compared the AUC of all pipelines on the validation dataset with FeAture Explorer (FAE) software. The pipeline using a PCC dimension reduction, relief feature selection, and gaussian process (GP) classifier yielded the highest area under the curve (AUC) using 15 features. When the “one-standard error” rule was used, FAE also produced a simpler model with 13 features, including S(5,-5)SumAverg, S(3,0)InvDfMom, Skewness, WavEnHL_s-3, Horzl_GlevNonU, Horzl_RLNonUni, 135dr_GlevNonU, WavEnLL_s-3, Teta4, Teta2, S(5,5)DifVarnc, Perc.01%, and WavEnLH_s-2. The AUCs of the training/validation/test datasets were 1.000/0.965/0.979, and the accuracies, sensitivities, and specificities were 0.890, 0.880, and 0.920, respectively. The best algorithm was GP whose AUCs of the training/validation/test datasets by the two-dimensional reduction methods and four feature selection methods were greater than approximately 0.800. Especially, the AUCs of different datasets were greater than approximately 0.900 using the PCC, RFE/Relief, and GP algorithms.

Conclusions

We demonstrated the feasibility of combining artificial intelligence and the radiomics from Fs-T2WI to differentially diagnose SRCMTs and Non-SRCMTs. This non-invasive approach could be very promising in clinical oncology.

Diffuse Large B-Cell Lymphoma of the Left Upper Extremity Mimicking a Sarcoma

Diffuse large B-cell lymphoma (DLBCL) can arise in both lymph nodes and extranodal sites. DLBCLs rarely present in the soft tissue of the upper extremity. We report a case of a 64-year-old woman who presented with a large left upper arm mass and underwent surgical resection under the presumptive diagnosis of sarcoma but the final pathology showed DLBCL. Sarcomas are common malignant tumors of the soft tissue of the extremities, but lymphomas also occasionally present as a soft tissue mass. It is important to keep lymphomas in mind in order to avoid unnecessary surgical excisions.

Lobular to Lobule: Metastatic Breast Carcinoma to Olfactory Neuroblastoma

Tumor-to-tumor metastasis (TTM) is a rare, but well-described phenomenon occurring in patients with multiple synchronous or metachronous primary malignancies. Olfactory neuroblastoma (ONB) is a rare malignant, neuroectodermal sinonasal tract tumor that occurs within the ethmoid sinus involving the cribriform plate. Very few cases of ONB have been documented to metastasize to other primary malignancies, but the reverse scenario is exceptional. During an evaluation for anosmia, a right nasal polyp was identified on imaging and endoscopy in a 66-year-old woman, with a polypectomy performed. Histologic examination showed classical features of a low-grade olfactory neuroblastoma, but within the tumor were isolated epithelioid cells which were strongly pancytokeratin immunoreactive. Review of the clinical history revealed lobular breast carcinoma treated 10 years earlier. Further evaluation with immunohistochemistry showed strong and diffuse nuclear estrogen and progesterone receptor reactivity, along with GATA3. These results confirmed TTM of an invasive lobular breast carcinoma to ONB. By employing a limited immunohistochemistry panel for all small round blue cell tumors that includes pancytokeratin, p40, S100 protein, SOX10, synaptophysin, desmin, CD99, and CD45, one is able to more accurately diagnose the classical tumor types, while also showing potentially unusual tumor features or exceptionally rare events like metastatic lobular breast carcinoma to ONB.

The vomeronasal organ: History, development, morphology, and functional neuroanatomy

The human vomeronasal organ (VNO) is an accessory olfactory organ located on the anteroinferior part of the nasal septum, 1.5-2.5cm from the nostrils. Its main role is pheromone reception and, through its anatomical connections with the central nervous system, especially parts of the hypothalamus, modulation of both social and sexual behavior, although these relations have been established only in nonprimates and very little is yet established for the structure and function of the human VNO. Morphologically, the human VNO is a pit or duct-shaped structure, comprised of three cellular layers-basal cells, neural cells with olfactory cell morphology and immunohistochemical phenotype, and ciliated respiratory epithelium. Medially and connected to the VNO, a small nerve fiber is found that runs longitudinally to the nasal septum and is considered by some to be a distant process of the Cranial Nerve 0 or terminal nerve. In addition to pheromone reception, the human VNO has also been associated with several pathological conditions, including sinus septi nasi, posttraumatic stress disorder, and ectopic olfactory esthesioblastoma.

Orbital invasion by Esthesioneuroblastoma: a comparative case series and review of literature

Purpose: To review the current literature on esthesioneuroblastoma (ENB) as it pertains to clinical features, grading systems, treatment options, and survival.Methods: A literature search in PubMed was performed to include all articles published in English with orbit involving ENB. Only articles that included each patient's demographics, tumor stage, treatment, or survival were included. A total of 22 articles with 104 patients were considered for this literature review. We also present five cases of ENB, all encountered in our health system, between 2010 and 2020.Results: The median age of diagnosis of orbit involving ENB was 44.5 years. Males were more likely affected than females at 72.9%. Common presenting ocular symptoms were visual change (38.1%), periorbital pain (33.3%), and diplopia (14.3%). Common clinical exam findings were proptosis (47.6%), extraocular movement deficit (23.8%), and periorbital edema (19.0%). Twenty-seven patients (77.1%) received surgery, 22 patients (62.9%) received chemotherapy, and 30 patients (85.7%) received radiation therapy as part of their treatment. Median duration of survival was 124.0 months and 5-year overall survival (OS) was 67.1%. Hyams, Kadish, and Dulguerov T-staging showed inconsistent survival prognosis while orbital invasion and lymph node metastasis had worse outcomes. Our five cases exhibited the spectrum of disease processes evidenced above, with four involving the orbit.Conclusions: ENB is a rare sinonasal tumor that can invade the orbit. Because of its rarity, no single staging system appears superior. Resection with radiation therapy has superior survival results while the benefits of chemotherapy are currently unknown.

Merkel Cell Carcinoma of the Maxillary Sinus: An Unusual Presentation of a Common Tumor

Merkel cell carcinoma is most commonly seen in the skin of sun exposed areas, particularly the head and neck and is associated with Merkel cell polyomavirus. Merkel cell carcinoma at an extracutaneous mucosal site of the head and neck is rare. We report a case of a 74-year-old women who presented with an enlarging thyroid mass found to be neuroendocrine carcinoma consistent with Merkel cell carcinoma (positive for synaptophysin, chromogranin, CK20). Subsequent work up revealed a maxillary sinus mass with extension into the nasal cavity. Biopsy was diagnostic for Merkel cell carcinoma (positive for synaptophysin, chromogranin, CK20 and Merkel cell polyomavirus). There are only case reports and small case series of Merkel cell carcinoma arising in the mucosal sites of the head and neck most commonly in the oral cavity, rarely the sinonasal mucosa. Merkel cell carcinoma metastasizing to the thyroid has only been reported in three other case reports, all from skin primaries. In addition to our case, we review the literature of extracutaneous sinonasal Merkel cell carcinoma and metastases to the thyroid.

Middle Ear and Temporal Bone Nonkeratinizing Squamous Cell Carcinomas With DEK-AFF2 Fusion: An Emerging Entity

Primary squamous cell carcinomas (SCCs) of the middle ear and temporal bone are rare and usually keratinizing by morphology. Nonkeratinizing, basaloid SCCs arising in this area are exceedingly rare, and, due to the anatomic proximity to the skull base, nasopharynx, and nasal sinuses, the differential diagnosis is broad. Most tumors with squamous differentiation arising in these subsites are either viral-induced (human papillomavirus/Epstein-Barr virus) or rarely may have specific molecular alterations (BRD4-NUT, EWSR1-FLI translocations). Occasional tumors are negative for these findings, and their pathogenesis is unknown. A recently discovered DEK-AFF2 fusion was clinically detected in a series of 2 cases known to the authors. This fusion has been previously reported in the literature in a patient with a base of skull tumor who was an exceptional responder to programmed cell death protein 1 inhibitor therapy. We examine here the histomorphologic and molecular findings of 2 additional cases of an emerging entity. Two male patients were identified. Each had a primary middle ear/temporal bone mass with locally advanced disease. The histology was reviewed, and immunohistochemistry was performed. RNA-based next-generation sequencing was performed for clinical detection of diagnostic or actionable fusions. Both patients had basaloid/nonkeratinizing tumors on biopsy. They were positive for markers of squamous differentiation (HMWK, CK5, and p40). By RNA sequencing, they demonstrated the presence of a DEK-AFF2 fusion and were negative for EWSR1 and NUT translocations. The DEK-AFF2 fusion may define a novel diagnostic category of middle ear and temporal bone nonkeratinizing/basaloid SCCs. This fusion also may represent a potential avenue for immunotherapy in these patients. Further studies are needed to fully explore whether this fusion defines a location-specific clinicopathologic entity.

Intraoperative squash cytology provides a qualitative intraoperative diagnosis for cases in which frozen section yields a diagnosis of equivocal brain tumour

OBJECTIVE

We assessed whether intraoperative squash cytology could provide surgeons with a qualitative diagnosis of brain lesions when frozen section diagnosis is equivocal.

METHODS

The study included 51 lesions that were diagnosed intraoperatively as equivocal brain tumour on the basis of frozen section. We retrospectively classified the lesions into five groups according to the final histopathological diagnoses (I: malignant lymphomas; II: diffuse astrocytic and oligodendroglia tumours; III: pituitary adenomas, IV: metastatic carcinomas; V: others). We assessed the squash cytology features of Groups I-IV and of the specific lesion types, and compared features among the groups.

RESULTS

The four groups differed in a range of salient cytomorphological features: lymphoglandular bodies in Group I (eight of nine cases), cytoplasmic fibrillary processes in Group II (six of eight cases), low-grade nuclear atypia in Group III (seven of seven cases), and large nuclei (approximately 80 μm² ) and nuclear crush artefacts in Group IV (seven of nine cases).

CONCLUSION

Findings of lymphoglandular bodies on intraoperative squash cytology can be considered characteristic of malignant lymphomas, while cytoplasmic fibrillary processes indicate diffuse astrocytic and oligodendroglial tumours. We conclude that squash cytology could yield a qualitative intraoperative diagnosis in over 25% of cases for which frozen section yields a diagnosis of equivocal brain tumour.

Diffusion Kurtosis Imaging and Intravoxel Incoherent Motion in Differentiating Nasal Malignancies

OBJECTIVES/HYPOTHESIS

To evaluate the usefulness of diffusion kurtosis imaging (DKI) and intravoxel incoherent motion (IVIM) in the differentiation of sinonasal malignant tumors (SNMTs) with different histological types.

STUDY DESIGN

Retrospective observational and diagnostic study.

METHODS

Sixty-five patients with SNMTs who underwent DKI and IVIM were enrolled in this retrospective study, including 27 squamous cell carcinomas (SCCs), 13 olfactory neuroblastomas (ONBs), 14 malignant melanomas (MMs) and 11 lymphomas. The kurtosis (K) and diffusion coefficient (Dk) from DKI and the pure diffusion coefficient (D), pseudodiffusion coefficient (D*), perfusion fraction (f), and the product of D* and f (f∙D*) from IVIM were measured. Kruskal-Wallis and Dunn multiple comparison tests with Bonferroni correction, receiver operating characteristic curve, and logistic regression analyses were used for statistical analysis.

RESULTS

Lymphomas demonstrated the highest K values but lowest Dk, D, D*, f, and f∙D* values among these four malignant tumors. ONBs exhibited high K values and MMs had highest D*, f, and f∙D* values. The cutoff value of ≤0.887 × 10^-3 mm² /sec for f∙D* provided a sensitivity, specificity, and an accuracy of 100%, 98.1%, and 98.5%, respectively, for differentiating lymphomas from the other three entities. The combination of f∙D* and D values showed a sensitivity of 92.9% and a specificity of 92.5% for the discrimination of MMs from ONBs and SCCs. The K value was useful for differentiating ONBs from SCCs, with a threshold value of 0.942 (sensitivity, 84.6%; specificity, 63.0%).

CONCLUSIONS

The combined use of DKI and IVIM is helpful for differentiating among four histological types of SNMTs.

LEVEL OF EVIDENCE

3 Laryngoscope, 2019.

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.

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.

Positron emission computed tomography and magnetic resonance imaging features of sinonasal small round blue cell tumors

AIM

The sinonasal tract hosts numerous types of undifferentiated neoplasms, having small round cell morphology. The aim of this study was to determine whether sinonasal small round blue cell tumors (SRBCT) have distinct imaging features on computed tomography (CT), magnetic resonance imaging (MRI), and 18-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET)/CT.

METHODS

Seventy-three patients (43 male; M_age = 61.2 years) with histopathologically proven sinonasal SRBCT were retrospectively reviewed. Imaging features of SRBCTs including location, maximum dimension, margin characteristics, presence of calcification, sclerotic bone changes, intratumoral necrosis, tumor extension, bone destruction, bone remodeling, perineural spread, T1- and T2-weighted MRI signal intensity, qualitative features on diffusion-weighted imaging and ¹⁸F-FDG PET/CT, and pattern of contrast enhancement were analyzed using Fisher's exact test or the chi-square test. The maximum standardized uptake values (SUV_max) and apparent diffusion coefficient (ADC_mean) values of SRBCT were compared by utilizing the Kruskal-Wallis test.

RESULTS

There was a significant difference between SRBCT type regarding the tumor location (p = 0.006), ¹⁸F-FDG uptake pattern (p = 0.006), involvement of the orbit (p = 0.016) and pterygopalatine fossa (p = 0.043), the presence of perineural spread (p < 0.001), bone destruction (p = 0.034), and intratumoral necrosis (p = 0.022). Bone destruction and necrosis were more common in rhabdomyosarcoma. Perineural spread was common in sinonasal adenoid cystic carcinoma (ACC). Qualitative ¹⁸F-FDG uptake features as well as tumor location were significantly different between sinonasal ACC and sinonasal undifferentiated carcinoma. The ADC_mean and SUV_max values were not statistically different between SRBCT types.

CONCLUSIONS

Sinonasal SRBCTs have numerous distinct imaging features on CT, MRI, and ¹⁸F-FDG PET/CT that could be useful in the differentiation between lesions when the histopathologic diagnosis is inconclusive.

Management of Locally Advanced Esthesioneuroblastoma in a Pregnant Woman

Esthesioneuroblastoma (ENB) is a rare malignant tumor that commonly develops in the upper nasal cavity. Standard treatment is not established, especially in locally advanced disease which portends the worse prognosis. Hereby, we report a case of a 27-year-old, 23-week pregnant woman, with a 2-month history of progressively growing right cervical lymphadenopathy, nasal obstruction, anosmia, frequent episodes of epistaxis, and right frontal headache. Imagiological evaluation revealed a lesion with 7×5,2×3,2 cm in the nasal fossae with extension to the ethmoidal complex and right olfactive fend and invasion of the endocranial compartment associated with lymphadenopathy. The biopsy revealed a high-grade EBN. Neoadjuvant chemotherapy with cisplatin and etoposide was administrated during pregnancy and continued after delivery up to 6 cycles of treatment with partial response. Radiotherapy followed, with complete response. This case report is intended to highlight that a high grade of suspicion should be kept in the presence of nonspecific symptoms of nasal obstruction, anosmia, facial pain, and/or headache and focus that chemotherapy is an important component of a combined-treatment modality for locally advanced ENB that can be used during pregnancy in a lifesaving situation.

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

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

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.

Whole-tumor histogram analysis of monoexponential and advanced diffusion-weighted imaging for sinonasal malignant tumors: Correlations with histopathologic features

BACKGROUND

The histopathological basis of monoexponential diffusion-weighted imaging (DWI), intravoxel incoherent motion (IVIM), and diffusion kurtosis imaging (DKI) in the characterization of sinonasal malignant tumors is still unclear.

PURPOSE

To explore the correlations of histogram metrics from monoexponential DWI, IVIM, and DKI with histopathologic features in sinonasal malignant tumors.

STUDY TYPE

Retrospective.

SUBJECTS

In all, 76 patients with sinonasal malignant tumors.

FIELD STRENGTH/SEQUENCE

Fourteen different b values (b = 0, 50, 100, 150, 200, 250, 300, 350, 400, 800, 1000, 1500, 2000, and 2500 sec/mm² ) were used to perform different DWI models at 3.0T.

ASSESSMENT

The whole-tumor histogram metrics were calculated on the apparent diffusion coefficient (ADC), pure diffusion coefficient (D), pseudodiffusion coefficient (D*), perfusion fraction (f), diffusion kurtosis (K), and diffusion coefficient (Dk) maps. Histopathologic features, including nuclear, cytoplasmic, cellular, stromal fractions, and the nuclear-to-cytoplasmic (N/C) ratio, were measured.

STATISTICAL TESTS

Spearman correlations and stepwise multiple linear regression analyses were performed to determine the correlations between histogram metrics and histopathologic features.

RESULTS

ADC, Dk, and f histogram metrics showed significant correlations with investigated histopathologic features; D and K histogram metrics were significantly correlated with cellular, stromal, and nuclear fractions (all P < 0.05). Significant correlations between the 75th percentile of D and cytoplasmic fraction and between the kurtosis of K and the N/C ratio were observed (P < 0.05). The skewness of Dk, K, and the 75th percentile of D were independently associated with cellular and nuclear fractions; the skewness of Dk and K were independently associated with stromal fraction (P < 0.05).

DATA CONCLUSION

Monoexponential and advanced DWI histogram parameters were significantly correlated with histopathologic features in sinonasal malignancies.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:273-285.

Discordance in Preoperative and Postoperative Histopathology of Sinonasal Tumors

Background Head and neck surgical pathology has been shown to be prone to histopathologic diagnostic error that can adversely impact patient care due to inappropriate management. Sinonasal tumors, in particular, present a diagnostic challenge given the relative rarity and diversity in histology and thus may have higher rates of discordant histology. Objective The purpose of this study is to determine the rate of discrepancy between preoperative and postoperative diagnoses of sinonasal tumors. Methods Retrospective chart review was performed on 52 patients treated for sinonasal tumors between January 2013 and December 2016. Initial diagnosis on preoperative biopsy was compared to postoperative diagnosis rendered at a single tertiary care referral center. A discrepant diagnosis was regarded as any change in diagnosis that resulted in further refinement of therapy or prognosis. Results Eleven (21.2%) patients had discrepancy between the preliminary pathology and postsurgical diagnosis. Of these diagnoses, four involved a change from a benign to a more aggressive benign or malignant process, three involved reclassification of a malignant tumor to a more aggressive histology, and four involved change from an aggressive process to benign histology. In all 11 cases, alteration in management strategy was rendered. The majority of discordant diagnoses were of fibro-osseous lesions and small round blue cell tumors. Conclusion Sinonasal tumors exhibit a high degree of discordance from preoperative to postoperative diagnosis. Critical decision-making should be reserved until careful review of operative specimens is performed to minimize patient morbidity and unnecessary interventions.

Data Set for the Reporting of Mucosal Melanomas of the Head and Neck: Explanations and Recommendations of the Guidelines From the International Collaboration on Cancer Reporting

Standardized pathologic reporting for cancers allows for improved communication for patient care and prognostic determination. If used universally, synoptic reporting enhances comparing data globally for scientific leverage. The International Collaboration on Cancer Reporting is a nonprofit organization whose mission is to develop evidence-based, universally available surgical pathology reporting data sets. Multiple different sites within the head and neck may be affected by mucosal melanoma, whose behavior and patient outcome are not equivalent to carcinomas of the corresponding sites. Factors such as Breslow thickness and Clark depth of invasion applied to cutaneous melanomas do not yield any prognostic significance in mucosal sites, and thus are not meaningful. Likewise, margin assessment is unique in head and neck sites. Further, the genetic profile of mucosal melanomas is different from that of most cutaneous tumors. Thus, within the head and neck region, mucosal melanoma is a distinct entity for which a dedicated data set was developed for implementation. The elements that comprise the core (required) and noncore (recommended) elements are discussed.

Intravoxel incoherent motion MRI for differentiating sinonasal small round cell malignant tumours (SRCMTs) from Non-SRCMTs: comparison and correlation with dynamic contrast-enhanced MRI

AIM

To investigate the value of intravoxel incoherent motion (IVIM) in the differentiation of sinonasal small round cell malignant tumours (SRCMTs) from non-SRCMTs and to compare and correlate these results with those of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Ninety patients with histologically confirmed sinonasal malignant tumours (53 SRCMTs and 37 non-SRCMTs) who underwent conventional MRI, IVIM, and DCE-MRI before treatment were enrolled. The IVIM and DCE-MRI parameters were measured. Statistical analyses were performed using Student's t-tests, receiver operating characteristic (ROC) curve analyses, and Spearman's correlation coefficients.

RESULTS

A lower pure diffusion coefficient (D) value and a higher pseudo-diffusion coefficient (D*) value were found in the sinonasal SRCMTs than in the non-SRCMTs (p<0.001 and p=0.011, respectively). Moreover, the mean extravascular extracellular space volume ratio (V_e) of the SRCMTs was significantly lower than that of the non-SRCMTs (p=0.020). ROC curve analysis showed that the diagnostic performance of D outperformed those of the other perfusion and diffusion parameters. A cut-off D value of 0.56 ×10^-3 mm²/s yielded a sensitivity of 80.4%, a specificity of 75%, and an accuracy of 78.2%, with an AUC of 0.825. Significant but poor-to-fair correlations were found between the parameters from IVIM and DCE-MRI.

CONCLUSIONS

The D and D* values of IVIM and the V_e value of DCE-MRI are helpful in distinguishing sinonasal SRCMTs from non-SRCMTs, with the D values having the best diagnostic efficiency.

NUT carcinoma of the sinonasal tract infiltrating the orbit in a man with birdshot chorioretinitis

A 48-year-old man with a history of birdshot chorioretinitis presented with blurry vision, retro-bulbar pain and sinusitis. Though visual acuity was unaffected, he had left optic disc oedema and mild restriction of left eye abduction. His symptoms progressed quickly, with diplopia in primary gaze, epistaxis from his left nostril, and a left relative afferent pupillary defect (RAPD). On computed tomography, there was a mass in the nasal cavity that extended through the left cribriform plate and lamina papyracea and posteriorly into the optic canal.

Pathological examination of biopsy specimens revealed sheets of undifferentiated cells with extensive areas of necrosis and islands of squamous differentiation. The tumour cells expressed monokeratin, p63, CD34, and p16. Molecular testing indicated rearrangement of the NUTM1 (15q14) locus and fusion of the NUTM1 and BRD4 (19p13.12) loci, confirming the diagnosis of NUT carcinoma of the sinonasal tract.

This is the first reported case of NUT carcinoma in a patient with birdshot chorioretinitis. The onset of chorioretinitis may have been the earliest sign of the effects of the BRD4-NUTM1 fusion protein, resulting in expression of HLA-A29. There is evidence that bromodomain and extra terminal (BET) family proteins play a role in inflammatory marker expression.

Atypical presentation of blastic plasmacytoid dendritic cell neoplasm: A potential diagnostic pitfall in nasal cavity

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare disease with an aggressive clinical course resulting in median survival times of 12 to 14 months.¹ It represents approximately 0.8% of primary cutaneous lymphomas.² According to the World Health Organization Classification of Tumors of Hematopoietic and Lymphoid Tissue, published in 2008, BPDCN is defined as an acute myeloid leukemia related precursor neoplasm, derived from precursors of the plasmacytoid dendritic cell. It is characterized microscopically by its dense monomorphous infiltrates of medium-sized blastoid morphology and expression of CD4 and CD56, as well as the absence of any common myeloid, T-lymphoid, B-lymphoid, and natural killer-lymphoid lineage markers.³ A few series of BPDCN have been reported in the literature, but very few cases of BPDCN have been described with lack of skin manifestation at the time of diagnosis.⁴ Here, we report a rare case of BPDCN in the nasal cavity.

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.

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.