Ciliated Adenosquamous Carcinoma: Expanding the Phenotypic Diversity of Human Papillomavirus-Associated Tumors

Prognostic implications across histological subtypes of head and neck squamous cell carcinoma: An update

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is one of the most common malignancies worldwide, arising from the mucosal epithelium of the oral cavity, oropharynx, hypopharynx, nasopharynx, larynx, and sinuses. In addition to the conventional morphologic pattern characterized by the degree of cellular atypia and squamous differentiation, HNSCC is classified into eight histopathologic subtypes: basaloid, spindle cell, adenosquamous, cuniculatum, verrucous, lymphoepithelial, papillary, and acantholytic.

METHODS

This review provides a comprehensive review of the literature on the prognostic implications of the histological subtypes of HNSCC.

RESULTS

Although there is extensive literature on HNSCC, few studies specifically focus on the treatment and prognosis of its histopathologic subtypes. Among these subtypes, verrucous squamous cell carcinoma and carcinoma cuniculatum generally have a favorable prognosis, while others, such as basaloid and spindle cell squamous cell carcinoma, tend to follow a more aggressive clinical course.

CONCLUSION

In this review, we delve into the histopathological subtypes of HNSCC and explore their clinicopathological, molecular, and prognostic findings. Further molecular investigations aimed at identifying targeted therapies for these subtypes are necessary. Moreover, it is crucial to recognize the emerging histopathological variants documented in the literature, considering the ongoing limitations in prognostic assessment.

Primary cilia-associated signalling in squamous cell carcinoma of head and neck region

Squamous cell carcinoma (SCC) of the head and neck originates from the mucosal lining of the upper aerodigestive tract, including the lip, tongue, nasopharynx, oropharynx, larynx and hypopharynx. In this review, we summarise what is currently known about the potential function of primary cilia in the pathogenesis of this disease. As primary cilia represent a key cellular structure for signal transduction and are related to cell proliferation, an understanding of their role in carcinogenesis is necessary for the design of new treatment approaches. Here, we introduce cilia-related signalling in head and neck squamous cell carcinoma (HNSCC) and its possible association with HNSCC tumorigenesis. From this point of view, PDGF, EGF, Wnt and Hh signalling are discussed as all these pathways were found to be dysregulated in HNSCC. Moreover, we review the clinical potential of small molecules affecting primary cilia signalling to target squamous cell carcinoma of the head and neck area.

Morphologic Spectrum of HPV-associated Sinonasal Carcinomas

BACKGROUND

High-risk human papillomavirus (HR-HPV) infection has been increasingly recognized as a risk factor for sinonasal tract carcinomas. However the prevalence and prognostic significance of HPV-associated sinonasal carcinomas is not well known due to limited studies and inconsistency in HPV testing modalities in literatures. Morphologically, HPV-associated sinonasal carcinomas encompass a diverse group of tumors. HPV-associated sinonasal adenocarcinoma has not been reported. The purpose of this study was to determine the prevalence, morphologic spectrum and prognostic implication of HPV-associated sinonasal carcinomas.

METHODS

This cohort included 153 sinonasal carcinomas. Tissue microarrays were constructed. P16 immunohistochemistry and HR-HPV E6/7 in-situ Hybridization (ISH) were performed. Carcinomas were deemed HPV-associated based on a positive ISH testing. Clinicopathologic data was collected.

RESULTS

28/153 (18%) sinonasal carcinomas were HPV-associated. HPV-associated carcinomas consisted of 26 (93%) squamous cell carcinomas and variants, 1 (3.5%) HPV-related multiphenotypic sinonasal carcinoma and 1 (3.5%) adenocarcinoma. The HPV-associated adenocarcinoma closely resembled HPV-associated endocervical adenocarcinoma morphologically. HPV-associated carcinomas occurred in 8 (29%) women and 20 (71%) men with a median age of 66 years old. HPV-associated carcinomas were predominantly located at nasal cavity. A trend toward improved overall survival and progression free survival in HPV-associated carcinomas patients was observed, yet without statistical significance.

CONCLUSION

Our study identifies a novel HPV-associated sinonasal adenocarcinoma subtype, highlights the broad morphologic spectrum of HPV-associated sinonasal carcinomas, and supports routine p16 testing during pathology practice regardless of tumor subtype followed by a confirmatory HR-HPV testing. This practice is critical for studying the clinical behavior of HPV-associated sinonasal carcinomas.

Lacrimal sac ciliated HPV16 positive, adenosquamous carcinoma-A case report of a unique histological variant at this site and a review of the literature

A 47-year-old female developed a reddish swelling of the right medial canthus over 3 months. On examination, a red, firm mass, involving the right medial canthal and extending into the inferior fornix was present and the globe was displaced upwards and inwards. A staging MRI scan confirmed a lacrimal sac lesion with anterior orbit extension. After an equivocal biopsy, the patient underwent debulking surgery. Histology showed a lacrimal sac invasive adenosquamous carcinoma, comprising poorly differentiated squamous carcinoma and invasive adenocarcinoma areas arranged in a tubulo-glandular pattern. The adenocarcinoma harboured numerous cilia. p16 showed block positivity of both components and micro-dissected tissue from both areas showed the presence of HPV16 DNA by PCR. This is the first description of ciliated adenosquamous carcinoma of the lacrimal sac and this finding is placed into the context of what is known about ciliated head and neck adenosquamous carcinomas and the role of high-risk HPV.

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

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

The Milan System classification of Warthin tumor: A large institutional study of 124 cases highlighting cytologic features that limit definitive interpretation

BACKGROUND

Fine-needle aspiration (FNA) is highly accurate for the diagnosis of Warthin tumor (WT). However, there is a minor subset of WT cases that are more challenging to interpret. The goal of this study is to identify factors that limit definitive diagnosis of WT on FNA.

METHODS

All WT surgical specimens diagnosed during a 6.5-year study period were retrospectively identified and the preceding cytologic specimen diagnostic categories were analyzed. Of particular interest were WT cases with indeterminate or malignant interpretations. Cases that noted squamous or mucinous change in either the surgical or cytologic reports were also reviewed.

RESULTS

A total of 157 WT surgical specimens were identified, with 124 (79.0%) having prior FNAs. The distribution of cytologic diagnostic categories was 12 (9.7%) nondiagnostic, 10 (8.1%) nonneoplastic, 13 (10.5%) atypia of undetermined significance (AUS), 82 (66.1%) neoplasm: benign, 4 (3.2%) salivary gland neoplasm of uncertain malignant potential (SUMP), 2 (1.6%) suspicious for malignancy, and 1 (0.8%) malignant. Of the 20 cases in indeterminate/malignant categories, a majority noted either squamoid (9 of 20) or mucinous (2 of 20) changes. The remainder noted scant cellularity as a limiting factor to interpretation. Additionally, 27 cases mentioned squamous or mucinous change in the surgical or cytology report, with a wide spectrum of cytologic categorization including 2 (7.4%) nondiagnostic, 2 (7.4%) nonneoplastic, 7 (25.9%) AUS, 8 (29.6%) neoplasm: benign, 4 (14.8%) SUMP, 2 (7.4%) suspicious for malignancy, and 1 (3.7%) malignant.

CONCLUSIONS

This study identified 2 key causes for indeterminate or misclassification of WT on FNA: specimen hypocellularity and metaplastic changes. Recognition of the potential for squamous and mucinous metaplastic changes combined with observance of some helpful diagnostic clues such as the presence of crystalloids may aid in preventing diagnostic pitfalls.

A Novel Ciliated, Mucin-producing Variant of HPV-related Cervical Adenosquamous Carcinoma In Situ: A Case Report

Uterine cervical adenosquamous carcinoma in situ was originally defined as having either a uniform population of cells with features intermediate in appearance between glandular and squamous cells, or a mixture of distinct glandular and squamous components within a single lesion. The former type would likely be reclassified today as stratified mucin-producing intraepithelial lesion, while the latter type is vanishingly rare. Here, we report a novel case of bona fide adenosquamous carcinoma in situ, which exhibits 2 morphologically and immunophenotypically distinct components: (1) an inner glandular component composed of a single layer of p40-negative, ciliated, mucin-producing dysplastic columnar cells and (2) an outer p40-positive, stratified dysplastic squamous component otherwise identical to cervical intraepithelial neoplasia-3. Both components show block-positive staining for p16 and are positive for high-risk human papillomavirus RNA by in situ hybridization. Our finding expands the histological spectrum of human papillomavirus-associated preinvasive cervical lesions while also providing further evidence that human papillomavirus-driven processes can exhibit ciliated morphology.

Human Papillomavirus (HPV)-Related Carcinoma of the Oropharynx with Squamous Cell and Adenoid Cystic Carcinoma-Like Features: Report of a Case

We describe the heretofore unreported case of an HPV-related carcinoma of the palatine tonsil with distinct areas of squamous cell- and adenoid cystic carcinoma-like differentiation in a 54-year old patient. The morphological, immunophenotypic and molecular findings of the tumor are illustrated. We discuss the parallels between the tumor and HPV-related multiphenotypic sinonasal carcinoma (HMSC) which is well-known to exhibit adenoid cystic carcinoma-like features. A review of the literature of high-risk HPV-associated non-squamous carcinomas of the oropharynx is presented.

HPV-related carcinoma of the oropharynx: challenges on small biopsy specimens

Human papillomavirus (HPV)-related oropharyngeal carcinoma can morphologically mimic many processes from benign to malignant and lead pathologists to incorrectly diagnose them and/or use inappropriate diagnostic terminology. Recognition of HPV-related oropharyngeal carcinoma and its variants is critical for appropriate prognostic and therapeutic considerations in small biopsy material. Various pitfalls in diagnosing these tumors on limited biopsies are discussed herein.

Intra-Cystic (In Situ) Mucoepidermoid Carcinoma: A Clinico-Pathological Study of 14 Cases

AIMS

To report on the clinico-pathological features of a series of 14 intra-oral mucoepidermoid carcinomas showing exclusive intra-cystic growth.

Materials and methods

All mucoepidermoid carcinomas diagnosed in the period 1990–2012 were retrieved; the original histological preparations were reviewed to confirm the diagnosis and from selected cases, showing exclusive intra-cystic neoplastic components, additional sections were cut at three subsequent 200 m intervals and stained with Hematoxylin–Eosin, PAS, Mucicarmine and Alcian Blue, to possibly identify tumor invasion of the adjacent tissues, which could have been overlooked in the original histological preparations. Additionally, pertinent findings collected from the clinical charts and follow-up data were analyzed.

Results

We identified 14 intraoral mucoepidermoid carcinomas treated by conservative surgery and with a minimum follow up of five years. The neoplasms were located in the hard palate (nine cases), the soft palate (two), the cheek (two) and the retromolar trigone (one). In all instances, histological examination revealed the presence of a single cystic space, containing clusters of columnar, intermediate, epidermoid, clear and mucous-producing cells, the latter exhibiting distinct intra-cytoplasmic mucin production, as confirmed by PAS, Mucicarmine and Alcian Blue stains. The cysts were entirely circumscribed by fibrous connective tissue, and no solid areas or infiltrating tumor cell clusters were detected. Conservative surgical resection was performed in all cases, and no recurrences or nodal metastases were observed during follow up.

Conclusions

Mucoepidermoid carcinomas showing prominent (>20%) intra-cystic proliferation currently are considered low-grade tumors. In addition, we also unveil the possibility that mucoepidermoid carcinomas, at least in their early growth phase, may display an exclusive intra-cystic component and might be considered as in situ carcinomas, unable to infiltrate adjacent tissues and metastasize.

Ciliated HPV-Related Carcinoma: A Diagnostic Challenge on Frozen Section

Oropharyngeal squamous cell carcinomas associated with high risk HPV show a wide morphological spectrum, including papillary, adenosquamous, lymphoepithelioma-like and sarcomatoid. We report an interesting case of ciliated HPV-related carcinoma arising from tonsillar tissue in a 55-year-old man which was associated with HPV33. This rare variant has been described in only a handful of cases in the literature, and to our knowledge this is the first case specifically associated with HPV33. The presence of cilia is a potential diagnostic problem as it has been traditionally considered a feature of benignancy, and could pose a particular challenge on frozen section. The diagnostic challenges, differential diagnosis of this tumor and the association with HPV33 are discussed.

Head and Neck Cytopathology: Human Papillomavirus-Positive Carcinomas, Including Diagnostic Updates, Testing Modalities, and Recommendations

Oropharyngeal squamous cell carcinoma caused by transcriptionally active human papillomavirus (HPV) is now well established as a unique form of head and neck cancer. Given the high frequency of metastasis to cervical lymph nodes by HPV-positive oropharyngeal squamous cell carcinomas, fine-needle aspiration (FNA) represents a widely accepted method for the sampling and diagnosis of these cancers. The recently published College of American Pathologists Guideline (2017) provides recommendations for the effective performance and interpretation of high-risk (HR) HPV testing in head and neck squamous cell carcinoma (HNSCC), including testing on FNA samples of metastatic HNSCC to cervical lymph nodes. There is a wide range of options available for HR-HPV testing in cytologic specimens.

MAML2 Rearrangements in Variant Forms of Mucoepidermoid Carcinoma: Ancillary Diagnostic Testing for the Ciliated and Warthin-like Variants

Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy. Recent studies have shown that most MECs harbor gene fusions involving MAML2-an alteration that appears to be specific for MEC, a finding that could be diagnostically useful. While most cases of MEC are histologically straightforward, uncommon variants can cause considerable diagnostic difficulty. We present 2 variants of MEC for which MAML2 studies were crucial in establishing a diagnosis: a previously undescribed ciliated variant, and the recently described Warthin-like variant. All cases of ciliated and Warthin-like MEC were retrieved from the archives of The Johns Hopkins Hospital. Break-apart fluorescence in situ hybridization for MAML2 was performed on all cases. One ciliated MEC and 6 Warthin-like MECs were identified. The ciliated MEC presented as a 4.6 cm cystic lymph node metastasis originating from the tongue base in a 47-year-old woman. The Warthin-like MECs presented as parotid masses ranging in size from 1.2 to 3.3 (mean, 2.7 cm) in 4 women and 2 men. The ciliated MEC consisted of macrocystic spaces punctuated by tubulopapillary proliferations of squamoid cells and ciliated columnar cells. The Warthin-like MECs were comprised of cystic spaces lined by multilayered oncocytic to squamoid cells surrounded by a circumscribed cuff of lymphoid tissue with germinal centers. In these cases, the Warthin-like areas dominated the histologic picture. Conventional MEC, when present, represented a minor tumor component. MAML2 rearrangements were identified in all cases. Warthin-like MEC, and now a ciliated form of MEC, are newly described variants of a common salivary gland carcinoma. Unfamiliarity with these novel forms, unanticipated cellular features (eg, cilia), and morphologic overlap with mundane benign processes (eg, developmental ciliated cysts, Warthin tumor) or other carcinomas (eg, ciliated human papillomavirus-related carcinoma) may render these variants susceptible to misdiagnosis. These unusual variants appear to consistently harbor MAML2 fusions-a finding that establishes a clear link to conventional MEC and provides a valuable adjunct in establishing the diagnosis.

Human Papillomavirus-Associated Neoplasms of the Head and Neck

Human papillomavirus (HPV) is an essential causal factor in a subset of head and neck neoplasms, most notably oropharyngeal squamous cell carcinoma, for which HPV infection has important diagnostic, prognostic, and therapeutic implications. This article summarizes the current understanding of HPV-associated neoplasms of the head and neck, including the recently described carcinoma with adenoid cystic-like features. Salient clinical, gross, and microscopic features are discussed, and the utility of specific ancillary studies is highlighted.

Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Oropharynx

The changes for oropharyngeal lesions in the 2017 edition of the WHO/IARC Classification of Head and Neck Tumours reference book are dramatic and significant, largely due to the growing impact of high risk human papillomavirus (HPV). The upcoming edition divides tumours of the oral cavity and oropharynx into separate chapters, classifies squamous cell carcinomas (SCC) of the oropharynx on the basis of HPV status, abandons the practice of histologic grading for oropharyngeal SCCs that are HPV positive, recognizes small cell carcinoma of the oropharynx, and combines polymorphous low grade adenocarcinoma and cribriform adenocarcinoma of tongue and minor salivary glands under the single term "polymorphous adenocarcinoma." This review not only calls attention to these changes, but describes the rationale driving these changes and highlights their implications for routine clinical practice.

Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: What Is New in the 2017 WHO Blue Book for Tumors and Tumor-Like Lesions of the Neck and Lymph Nodes

The World Health Organization (WHO) 2017 Classification of Head and Neck Tumors ("Blue Book") will now include a new chapter on tumors and tumor-like lesions of the neck and lymph nodes, which was not included in the previous edition. Tumors and tumor-like lesions, including a variety of cysts and metastases, can arise in any component in the neck, including soft tissue, lymph nodes, and developmental remnants. The pathology and clinical features of metastatic carcinoma of unknown primary in the head and neck has changed dramatically in the last several years. Many of these tumors which were previously diagnosed as unknown primary are now identified as oropharyngeal and nasopharyngeal carcinomas related to human papillomavirus (HPV), less commonly to Epstein-Barr virus (EBV) and occasionally even to Merkel cell polyomavirus. Many unusual features can arise in these metastases, such as undifferentiated morphology, extensive cystic change with central degeneration, gland formation, and even ciliated cells. Rarely, carcinoma in the neck can arise in association with a heterotopic tissue, primarily thyroid or salivary gland tissue. Tumor-like lesions include branchial cleft cysts, thyroglossal duct cyst, dermoid and teratoid cyst, and ranula. Pathologists should be familiar with the diagnostic features and clinicopathologic corrections of these neck lesions in order to correctly diagnosis them and to provide for proper clinical management. This article will briefly describe the pathologic and clinical features of these entities as they are covered in the new 2017 Blue Book.

Morphologic diversity in human papillomavirus-related oropharyngeal squamous cell carcinoma: Catch Me If You Can!

As the human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma epidemic has developed in the past several decades, it has become clear that these tumors have a wide variety of morphologic tumor types and features. For the practicing pathologist, it is critical to have a working knowledge about these in order to make the correct diagnosis, not to confuse them with other lesions, and to counsel clinicians and patients on their significance (or lack of significance) for treatment and outcomes. In particular, there are a number of pitfalls and peculiarities regarding HPV-related tumors and their nodal metastases that can easily result in misclassification and confusion. This article will discuss the various morphologic types and features of HPV-related oropharyngeal carcinomas, specific differential diagnoses when challenging, and, if established, the clinical significance of each finding.