p16 overexpression in high-grade neuroendocrine carcinomas of the head and neck: potential diagnostic pitfall with HPV-related carcinomas

Primary Oral Mixed Neuroendocrine-Non-neuroendocrine Neoplasm (MiNEN): A Rare Case Report and Review of the Literature

Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) are rare tumors recently characterized by the presence of both neuroendocrine and non-neuroendocrine components within the same tumor tissue. Although MiNEN found their place in the WHO classification for various organs, this composite tumor in the head and neck region remains exceptionally rare. We present a case of primary oral MiNEN in a 64-year-old male located on the left side of lower gingiva. Biopsy raised suspicion of neuroendocrine carcinoma (NEC) and the patient underwent partial mandibulectomy. The resected specimen showed two distinct components of NEC and squamous cell carcinoma (SCC) with the confirmation of immunohistochemical markers. There has been no sign of recurrence nor metastasis 6 years after the surgery. In addition, we have conducted a review of published cases with potential relevance to this entity, resulting in five cases. The diverse terminology reinforces the need for a standardized classification system of oral/head and neck MiNENs.

Clinical Behavior, Mutational Profile and T-Cell Repertoire of High-Grade Neuroendocrine Tumors of the Head and Neck

Neuroendocrine carcinomas (NECs) of the head and neck (HN) account for <1% of HN cancers (HNCs), with a 5-year overall survival (OS) <20%. This is a retrospective study of HN NECs diagnosed at our institution between 2005 and 2022. Immunohistochemistry and next-generation sequencing (NGS) were used to evaluate neuroendocrine markers, tumor mutational burden (TMB), mutational profiles and T-cell receptor repertoires. Eleven patients with high-grade HN NECs were identified (male:female ratio 6:5; median age 61 (Min-Max: 31-86)): nasoethmoidal (3), parotid gland (3), submaxillary gland (1), larynx (3) and base of tongue (1). Among n = 8 stage II/IVA/B, all received (chemo)radiotherapy with/without prior surgery or induction chemotherapy, with complete response in 7/8 (87.5%). Among n = 6 recurrent/metastatic patients, three received anti-PD1 (nivolumab (2), pembrolizumab (1)): two achieved partial responses lasting 24 and 10 months. After a median follow-up of 30 and 23.5 months since diagnosis and since recurrent/metastatic, median OS was not reached. Median TMB (n = 7) was 6.72 Mut/Mb. The most common pathogenic variants were TP53, HNF1A, SMARCB1, CDKN2A, PIK3CA, RB1 and MYC. There were 224 median TCR clones (n = 5 pts). In one patient, TCR clones increased from 59 to 1446 after nivolumab. HN NECs may achieve long-lasting survival with multimodality treatment. They harbor moderate-high TMBs and large TCR repertoires, which may explain responses to anti-PD1 agents in two patients and justify the study of immunotherapy in this disease.

High-risk HPV-related squamous cell carcinoma in the temporal bone: a rare but noteworthy subtype

High-risk human papillomavirus (HPV) is a risk factor for the development of several head and neck squamous cell carcinomas (SCCs). However, there have been few reports of high-risk HPV infection in temporal bone squamous cell carcinomas (TBSCCs), and thus the prevalence and clinicopathologic significance of high-risk HPV in TBSCCs are still unclear. We retrospectively collected 131 TBSCCs and analyzed them for transcriptionally active high-risk HPV infection using messenger RNA in situ hybridization; we also assessed the utility of p16-immunohistochemistry (IHC) and Rb-IHC to predict HPV infection. Eighteen (13.7%) of the 131 TBSCCs were positive for p16-IHC, and five of them were positive for high-risk HPV infection (the estimated high-risk HPV positivity rate was 3.8% [5/131]). Interestingly, all five HPV-positive patients were male and had TBSCC on the right side. In the p16-IHC⁺/HPV⁺ cases (n = 5), the Rb-IHC showed a partial loss pattern (n = 4) or complete loss pattern (n = 1). In contrast, all p16-IHC-negative cases (n = 113) showed an Rb-IHC preserved pattern. The positive predictive value (PPV) of p16-IHC positivity for high-risk HPV infection was low at 27.8%, while the combination of p16-IHC⁺/Rb-IHC partial loss pattern showed excellent reliability with a PPV of 100%. The prognostic significance of high-risk HPV infection remained unclear. High-risk HPV-related TBSCC is an extremely rare but noteworthy subtype.

Top 10 Basaloid Neoplasms of the Sinonasal Tract

BACKGROUND

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

METHODS

Review.

RESULTS

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

CONCLUSION

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

Human papillomavirus status and prognosis of oropharyngeal high-grade neuroendocrine carcinoma

BACKGROUND

The prognostic impact of human papillomavirus (HPV) infection or smoking on oropharyngeal high-grade neuroendocrine carcinoma (HG-NEC) is not established.

METHODS

Retrospective study with patients with oropharyngeal HG-NEC seen at MD Anderson Cancer Center from 1997 to 2020, and previously reported patients with oropharyngeal HG-NEC and known p16 and HPV status from the literature review. Survival was estimated with the Kaplan-Meier method, and survival differences assessed with the log-rank test and Cox proportional hazards models.

RESULTS

Thirty patients were included; most had a heavy (≥10 pack-years) smoking history (52%), locoregional disease (stage III-IVB; 77%), and p16-positive tumor (92%). HPV was positive in 65% of tested samples (15/23). Of 24 patients treated with curative intent, the objective response rates was 90% (9/10) and 81% (17/21), respectively, for induction chemotherapy and definitive radiotherapy. During follow-up, 54% (13/24) recurred, mostly (11/13) at distant sites. Median overall survival (OS) was 46 months (95% CI, 14.3 - NA). OS was not associated with HPV status (HR 0.73, P = 0.6) or smoking (HR 1.16, P = 0.8). Among 63 patients with known HPV status after the literature review (19 HPV- and 44 HPV + ), HPV status remained unassociated with OS (P = 0.92).

CONCLUSIONS

This is the largest retrospective cohort of oropharyngeal HG-NEC. Distant recurrence rate after curative treatment was high, suggesting that multimodality treatment including systemic therapy may benefit patients with locally advanced disease. HPV infection did not affect survival outcomes, therefore should not lead to therapy de-intensification for this histology.

Positive clinical outcomes following therapy with programmed cell death protein 1/programmed cell death ligand 1 inhibitors in neuroendocrine carcinoma of the cervix

Neuroendocrine carcinoma of the cervix (NECC) is a highly aggressive and rare gynecological malignancy with a poor prognosis. Despite aggressive local and systemic treatments, there are high rates of locoregional recurrence and distant metastases. Therefore, more potent treatments are required to manage NECC. In recent years, emerging immune checkpoint inhibitors, such as programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) inhibitors, have been used in treating various solid tumors and provide a new direction for immune-targeted therapy for NECC. In this review, we summarize the biomarkers useful for the evaluation of the therapy with PD-1/PD-L1 inhibitors in patients with NECC and the clinical applications and prospects of monotherapy with PD-1/PD-L1 inhibitors and combinations with other therapies in patients with NECC. In some individual case reports, therapeutic strategies with PD-1/PD-L1 inhibitors showed good efficacy. Further studies are needed to confirm the possibility of using PD-1/PD-L1 inhibitors as a standard treatment strategy in NECC.

Human Papillomavirus-Associated Combined Neuroendocrine and Squamous Cell Carcinoma of the Sinonasal Tract

Combined neuroendocrine and squamous cell carcinoma (SCC) of the sinonasal tract is rare entity but is increasingly gaining recognition within the head and neck pathology community. In a recent series, a single case was reported to demonstrate diffuse p16 positivity despite lacking high-risk human papillomavirus (HPV) by RNA in-situ hybridisation (ISH). Here we describe a case of p16 positive combined neuroendocrine and SCC containing high-risk HPV. Retrospective case review of sinonasal carcinomas within the Head and Neck Pathology Department at Guy's and St Thomas' NHS Foundation Trust identified a single case of combined neuroendocrine and SCC. Clinico-demographic data was obtained through electronic hospital records. All immunohistochemistry and in-situ hybridisation were undertaken according to departmental standard operating procedures. Routine microscopy showed the tumour to comprise small and large cell neuroendocrine components as well as squamous and spindle cell elements. Small and large cells demonstrated CD56 and synaptophysin expression, whereas CK5/6 and p63 were confined to squamous components. There was diffuse p16 expression and punctate nuclear positivity for DNA ISH. We describe a case of HPV-associated combined neuroendocrine and SCC of the sinonasal tract. Recognition of HPV association with this entity avoids diagnostic pitfalls.

High prevalence of p16 staining in malignant tumors

p16 (CDKN2A) is a member of the INK4 class of cell cycle inhibitors, which is often dysregulated in cancer. However, the prevalence of p16 expression in different cancer types is controversial. 15,783 samples from 124 different tumor types and 76 different normal tissue types were analyzed by immunohistochemistry in a tissue microarray format. p16 was detectable in 5,292 (45.0%) of 11,759 interpretable tumors. Except from adenohypophysis in islets of Langerhans, p16 staining was largely absent in normal tissues. In cancer, highest positivity rates were observed in uterine cervix squamous cell carcinomas (94.4%), non-invasive papillary urothelial carcinoma, pTaG2 (100%), Merkel cell carcinoma (97.7%), and small cell carcinomas of various sites of origin (54.5%-100%). All 124 tumor categories showed at least occasional p16 immunostaining. Comparison with clinico-pathological data in 128 vulvar, 149 endometrial, 295 serous ovarian, 396 pancreatic, 1365 colorectal, 284 gastric, and 1245 urinary bladder cancers, 910 breast carcinomas, 620 clear cell renal cell carcinomas, and 414 testicular germ cell tumors revealed only few statistically significant associations. Comparison of human papilloma virus (HPV) status and p16 in 497 squamous cell carcinomas of different organs revealed HPV in 80.4% of p16 positive and in 20.6% of p16 negative cancers (p<0.0001). It is concluded, that a positive and especially strong p16 immunostaining is a feature for malignancy which may be diagnostically useful in lipomatous, urothelial and possibly other tumors. The imperfect association between p16 immunostaining and HPV infection with high variability between different sites of origin challenges the use of p16 immunohistochemistry as a surrogate for HPV positivity, except in tumors of cervix uteri and the penis.

Systematic review of neuroendocrine carcinomas of the oropharynx

Data describing features and management of oropharyngeal neuroendocrine carcinomas (NEC) remain sparse. A systematic review was performed. Patients were stratified by treatment modality and examined for disease progression and survival outcomes. Ninety-four patients from 50 publications were included. Average age at diagnosis was 59.7 years (range 14-83). 73.4% were male. Most studies did not document HPV status. Forty patients (85.1%) were p16 positive, and 34 (85.0%) were HPV-ISH positive. Overall survival was 75.4% at 1 year, and 40.0% at 2 years. Of patients with locoregional disease, 33.8% developed distant metastasis. 12.5% of patients developed locoregional recurrence. Patients who developed distant metastases had worse overall survival (p = 0.0004). No significant difference was found between treatment modalities. Human papilloma virus may be associated with oropharyngeal NEC. Current treatments provide locoregional control, but distant metastases are common and confer low overall survival.

High-risk HPV-related Squamous Cell Carcinoma in the Conjunctiva and Lacrimal sac: Clinicopathologic Characteristics and Diagnostic Utility of p16 and Rb Immunohistochemistry

High-risk human papillomavirus (HPV) infection in conjunctival and lacrimal sac squamous cell carcinomas (SCCs) has been sporadically reported; however, its prevalence, clinicopathologic significance and surrogate markers have not been fully elucidated. Here, we attempted to clarify these questions in Japanese patients with conjunctiva and lacrimal sac SCCs. We retrospectively collected 51 conjunctival SCC and 7 lacrimal sac SCC samples and analyzed them for (1) transcriptionally active high-risk HPV infection using messenger RNA in situ hybridization and (2) protein expressions of p16 and Rb using immunohistochemistry (IHC). Among a total of 58 cases, 25 (43.1%) and 16 (27.6%) tumors were positive for p16-IHC and HPV in situ hybridization, respectively. Ten (19.6%) of the 51 conjunctival SCCs, especially in the palpebral conjunctiva, and 6 (85.7%) of the 7 lacrimal sac SCCs were positive for high-risk HPV. High-risk HPV infection was significantly associated with younger patients, nonkeratinizing SCC histology, p16-positivity and partial loss of Rb expression, but not with recurrence risk. Notably, p16-IHC was not a perfect surrogate marker for high-risk HPV infection; only 64% (16/25) of p16-positive tumors were positive for high-risk HPV. In contrast, the p16+/Rb partial loss pattern was exclusively correlated with high-risk HPV-positivity. The results suggest that the combination of p16 and Rb expression patterns by IHC could be a useful method to predict high-risk HPV infection in conjunctival and lacrimal sac SCCs. HPV infection may be of less prognostic value in this field of cancers.

Large cell neuroendocrine carcinoma originating in the subglottic larynx

Large cell neuroendocrine carcinoma (LCNEC) of the larynx is an exceedingly rare cancer of the head and neck that is difficult to diagnose. Few case reports of laryngeal LCNEC exist within the literature, and it was not until recently that LCNEC was recognized as a discrete subtype of neuroendocrine carcinoma. Given its recent recognition as a distinct subtype, histologic characteristics distinguishing LCNEC from other poorly differentiated carcinomas remain under investigation. Various reports have shown genetic alterations such as p53 and/or p16 overexpression, which are typically associated with infection by human papilloma virus (HPV). However, some reports have shown p53 and/or p16 overexpression in HPV negative samples. In this case, we discuss a 67-year-old patient with a history of extensive alcohol and tobacco use with a newly diagnosed T4N0M0, high grade, LCNEC of the subglottic larynx. Tumor pathology demonstrated positive staining for typical neuroendocrine (NE) markers like synaptophysin and chromogranin A; however, there was diffuse CK34βE12 and p16 expression. LCNEC is a newly classified subtype of poorly differentiated neuroendocrine (NE) tumors, and the diagnosis requires consideration of the clinical presentation, microscopic features, and immunostaining markers.

Prognostic Analysis of HPV Status in Sinonasal Squamous Cell Carcinoma

Sinonasal squamous cell carcinoma (SNSCC) is a rare and aggressive malignancy with poor prognosis. Human papilloma virus (HPV) can induce SNSCC although its incidence and impact on patients’ outcomes remains unclear. We performed a retrospective cohort study of patients with SNSCC treated consecutively in a comprehensive cancer center. HPV status was determined with p16 immunohistochemistry followed by RNA in situ hybridization (RNAscope). The incidence, clinical characteristics, and oncologic outcomes of HPV+SNSCC were assessed. P16 prognostic value was evaluated. Fifty-nine patients were included. Eleven (18.6%) SNSCC were p16+ with five (8.4%) doubtful cases. RNAscope was positive in nine cases (15.2%). Patients with HPV+SNSCC were younger (p = 0.0298) with a primary tumor originating mainly in nasal fossa (p < 10−4). Pathologic findings were not different according to HPV status. Among patients who were curatively treated, overall survival was better for HPV+SNSCC (p = 0.022). No prognostic value of p16 expression was reported. Patients with HPV+SNSCC have better oncologic outcomes, probably due to earlier tumor stage with primary location predominantly in the nasal fossa, a more suitable epicenter to perform a surgical resection with clear margins. P16 expression seems not to be a good surrogate of HPV status in SNSCC.

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

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

Update from the 5th Edition of the World Health Organization Classification of Head and Neck Tumors: Oropharynx and Nasopharynx

The new WHO classification of head and neck tumors provides a comprehensive overview of lesions by summarizing their clinical, epidemiological, histological, immunohistochemical, molecular and genetic features. The chapters related to the description of oropharyngeal and nasopharyngeal lesions have thus been largely modified.

Development of head and neck pathology in Europe

This review gives a brief history of the development of head and neck pathology in Europe from a humble beginning in the 1930s to the explosive activities the last 15 years. During the decades before the introduction of immunohistochemistry in the 1980s, head and neck pathology grew as a subspeciality in many European countries. In the late 1940s, the Institute of Laryngology and Otology with its own pathology laboratory was founded in London, and in 1964 the World Health Organization (WHO) International Reference Centre for the Histological Classification of Salivary Tumours was established at the Bland-Sutton Institute of Pathology, also in London. International collaboration, and very much so in Europe, led to the publication of the first WHO Classification of Salivary Gland Tumours in 1972. In the 1960s, a salivary gland register was organised in Hamburg and in Cologne the microlaryngoscopy was invented enabling microscopic endoscopic examination and rather shortly afterwards a carbon dioxide laser attached to the microscope became established and laryngeal lesions could be treated by laser vaporisation. During the last three decades, the use of immunohistochemistry supplemented with cytogenetic and refined molecular techniques has greatly facilitated the pathological diagnostics of head and neck lesions and has had a huge impact on research. Collaboration between different European centres has drastically increased partly due to establishment of scientific societies such as the Head and Neck Working Group (HNWG) within the European Society of Pathology and the International Head and Neck Scientific Group (IHNSG). A very large number of European pathologists have contributed to the 2nd, 3rd and 4th WHO books, and are involved in the upcoming 5th edition. Accredited educational meetings and courses are nowadays regularly arranged in Europe. Numerous textbooks on head and neck pathology have been written and edited by European pathologists. The increased collaboration has created larger series of tumours for research and new entities, mainly defined by their genetic abnormalities, are continuously emerging from Europe, particularly regarding salivary gland neoplasms and "undifferentiated" sinonasal tumours. These findings have led to a better and more precise classification and open the possibilities for new treatment strategies.

Undifferentiated and dedifferentiated head and neck carcinomas

Undifferentiated carcinomas arising at salivary gland and head and neck mucosal sites may originate either de novo or through a process of dedifferentiation of a differentiated carcinoma. While in the latter group the diagnosis is largely dependent on the identification of the differentiated component or recognition of a specific genotype, the classification of undifferentiated carcinomas that lack a differentiated component is mainly based on the identification of specific genetic drivers, like for example the NUTM1 fusions in NUT carcinoma. A further category is represented by virus associated carcinomas (mainly HPV and EBV), that frequently displays an undifferentiated morphology. Overall, these tumors often represent a diagnostic challenge, especially in small biopsies. This review summarizes and discuss the diagnostic approach to the main head and neck carcinoma types that frequently or occasionally display an undifferentiated appearance, with a focus on salivary gland, oropharyngeal, nasopharyngeal and sinonasal subsites.

Neuroendocrine Carcinoma of the Larynx and Pharynx: A Clinical and Histopathological Study

Simple Summary

Neuroendocrine carcinomas (NECs) of the head and neck are rare. The presented series of 20 patients with laryngeal and pharyngeal NECs is population-based and one of the largest published to date. We analyzed the treatment results according to the type of therapy and the role of various standard (synaptophysin-chromogranin-CD56, Ki-67, p16, HPV, and EBV) and some novel (INSM1 and PD-L1) neuroendocrine markers or potential prognosticators. The results indicate the following: (1) laryngeal and pharyngeal NECs accounted for 0.43% and 0.17% of the cases in the corresponding tumor groups, respectively; (2) neuroendocrine differentiation can be reliably determined by INSM1 immunohistochemistry; (3) the prognosis was determined by the nodal stage and TNM stage but not by the histological grade (which refers to moderately and poorly differentiated NECs); (4) except in well-differentiated NECs and early-stage (T1-2N0-1) moderately/poorly differentiated NECs, aggressive multimodal therapy is needed; and (5) the p16, HPV, and EBV statuses failed to show any prognostic value.

Abstract

Neuroendocrine carcinomas (NECs) of the head and neck are rare and the experience scanty. The Cancer Registry of Slovenia database was used to identify cases of laryngeal and pharyngeal NECs diagnosed between 1995–2020. Biopsies were analyzed for the expression of standard neuroendocrine markers (synaptophysin, chromogranin, CD56), INSM1, Ki-67, p16, and PD-L1 (using the combined positive score, CPS). In situ hybridization for human papillomavirus (HPV) and Epstein–Barr virus (EBV) was performed. Twenty patients (larynx, 12; pharynx, 8) were identified. One tumor was well differentiated (WD), five were moderately differentiated (MD), and 14 were poorly differentiated (PD). Disease control was achieved solely by surgery in 4/4 MD/PD T1-2N0-1 tumors. Eight patients died of the disease, seven of which were due to distant metastases. All three traditional markers were positive in 11/17 NECs and the INSM1 marker in all 20 tumors. Two of fourteen p16-positive tumors were HPV-positive, but all three nasopharyngeal NECs were EBV-negative. Three tumors had CPSs ≥ 1. In conclusion, INSM1 was confirmed to be a reliable marker of neuroendocrine differentiation. Except in WD and early-stage MD/PD tumors, aggressive multimodal therapy is needed; the optimal systemic therapy remains to be determined. p16, HPV, and EBV seem to bear no prognostic information.

P16INK4A expression might be associated with a favorable prognosis for cervical adenocarcinoma via dysregulation of the RB pathway

Previous studies have largely failed to clarify the relationship between p16^INK4A status and cervical adenocarcinoma prognosis. The current study aimed to examine the clinical and pathological significance of p16^INK4A expression in several cervical adenocarcinoma subtypes. Eighty-two samples collected from patients with cervical adenocarcinoma were formalin fixed and paraffin embedded. Next, p16^INK4A levels were analyzed with immunohistochemistry. Additionally, the relationship between p16^INK4A expression and clinicopathological factors as well as prognosis was evaluated. The expression of p16^INK4A was mostly detected in all usual cervical adenocarcinoma subtypes. In the gastric type, only a few cases were positive for p16^INK4A expression. Results of the Kaplan–Meier analysis indicated that the positive p16^INK4A expression in tumor cells was significantly associated with favorable progression-free survival and overall survival in patients with cervical adenocarcinoma (p = 0.018 and p = 0.047, respectively, log-rank test). Our findings suggest that the status of p16^INK4A expression may influence prognosis. Thus, p16^INK4A expression could be used as a biomarker for improving the prognosis of patients with cervical adenocarcinoma.

Impact of human papillomavirus in sinonasal cancer-a systematic review

BACKGROUND

Human papillomavirus (HPV) is an established prognostic marker in oropharyngeal squamous cell carcinoma. Currently, the role of HPV in sinonasal carcinoma is being explored.

OBJECTIVES

This systematic review addresses the role of HPV in sinonasal cancer, establishing the occurrence of HPV-positive cancers and the influence of HPV-positivity on prognosis in sinonasal cancer as well as the utility of the putative surrogate marker of HPV (p16) in sinonasal cancer.

MATERIAL AND METHODS

Studies were identified with searches of Medline via PubMed and Embase via OVID (4 May 2020). Articles on original research concerning sinonasal cancer and HPV in humans written in English were included. Case reports with less than five cases were excluded.

RESULTS

Initially, 545 articles were identified; 190 duplicate articles were removed leaving 355 articles for title/abstract screening. Title/abstract screening excluded 243 articles, leaving 112 studies assessed for eligibility. After full-text screening, 57 studies were included. All articles investigated the significance of HPV in sinonasal carcinomas. HPV was reported in approximately 30% of sinonasal squamous cell carcinoma (SNSCC), where it was associated with a better prognosis. In sinonasal cancer, p16 is associated with diagnostic pitfalls and a putative utility of p16 in SNSCC has yet to be established. HPV was not frequently reported in other types of sinonasal carcinomas, besides the recently described subtype, HPV-dependent Multiphenotypic Sinonasal Carcinoma. In other types of sinonasal carcinoma, HPV is not frequently found.

CONCLUSION

Approximately 30% of SNSCC are HPV-positive. HPV-positivity in SNSCC is associated with improved survival. HPV occurs only rarely in other sinonasal cancers. There is currently not sufficient evidence for p16 as a surrogate marker of HPV in SNSCC.

Neuroendocrine Neoplasms of the Larynx: A Clinicopathologic Analysis of 27 Neuroendocrine Tumors and Neuroendocrine Carcinomas

Laryngeal neuroendocrine neoplasms (NENs) are rare and heterogeneous, encompassing well-differentiated neuroendocrine tumors (NETs; grade 1, 2, and 3), neuroendocrine carcinomas (NECs, small cell and large cell types), and mixed neuroendocrine non-neuroendocrine neoplasms (MiNEN). We aimed to study the clinicopathologic spectrum of these neoplasms. A retrospective review of all primary laryngeal NENs diagnosed from 2005 to 2017 was undertaken. Mitotic index was divided into < 2, ≥ 2-10, and > 10 mitoses/2 mm², with a Ki-67 labelling index of < 2%, ≥ 2-20%, and > 20% for the NET grade 1, 2 and 3 categories, respectively. A total of 27 patients were included. The median age at presentation was 60 years; the male-to-female ratio was 8:1. Supraglottis (n = 22) was the most frequently affected subsite. There were 9 NETs grade 2 (G2), and 18 NECs cases. There were no NET grade 1 or 3 cases in our cohort. Among the NETs G2, the morphology was epithelioid (2), plasmacytoid (3), clear (2), oncocytic (1), and rhabdoid (1). Unique 'glomeruloid structures' (n = 5), calcification (n = 3), lymphoid aggregates (n = 5), intranuclear inclusions (n = 2), hyaline globules (n = 3), and Leisegang rings (n = 2) were identified. NECs comprised 16 small cell neuroendocrine carcinoma and 2 large cell neuroendocrine carcinoma. On immunohistochemistry, tumor cells expressed AE1/AE3 (86%), synaptophysin (100%), chromogranin (100%), INSM1 (100%), calcitonin (33.3%). In the NEC group, p53 aberrant expression (87.5%), Retinoblastoma (Rb) loss (88.2%), and diffuse p16 immunoreactivity (66.7%) were additionally observed. Lymph-node metastasis was detected in 62.5% and 85.7%, while distant metastasis in 55.6% and 76.9%, respectively in NET G2 and NEC. Laryngeal NENs are aggressive neoplasms with a high rate of nodal and distant metastasis. Awareness of the wide pathologic spectrum of laryngeal NENs and appropriate use of IHC is needed to render an accurate diagnosis. Ki67 assessment is strongly recommended for laryngeal NEN prognostication.

p16 positive oropharyngeal small cell cancer: A case report

Extra-pulmonary small cell carcinomas (EPSCC) are rare malignancies. Like small cell lung cancer (SCLC), they are aggressive malignancies with dismal prognosis. We here report a case of a middle-aged man who presented with odynophagia and cervical lymphadenopathy. Diagnostic workup confirmed the diagnosis of locally-advanced p16-positive oropharyngeal cancer (OPC) with a surprising histology of small cell cancer, suggesting a human papilloma virus (HPV)-related oropharyngeal cancer with small cell differentiation. HPV oropharynx infection is a well-known risk factor for squamous cell carcinoma of the oropharynx, but it is unknown if it may increase the risk of other OPC histology.

p16 overexpression and Rb loss correlate with high-risk HPV infection in oropharyngeal squamous cell carcinoma

AIMS

p16 is a sensitive surrogate marker for transcriptionally active high-risk human papillomavirus (HR-HPV) infection in oropharyngeal squamous cell carcinoma (OPSCC), but it is not sufficient in all clinical settings.

METHODS AND RESULTS

We examined the p16 and Rb expression status in 177 OPSCC cases by immunohistochemistry and the presence of transcriptionally active HR-HPV infection by mRNA in-situ hybridisation. The 177 cases were divided into p16⁺ /HPV⁺ (n = 105, 59.3%), p16⁺ /HPV^- (n = 8, 4.5%) and p16^- /HPV^- (n = 64, 36.2%) groups. The p16⁺ /HPV^- and p16^- /HPV^- groups had a trend towards worse overall survival (OS) or significantly worse OS than the p16⁺ /HPV⁺ group (n = 105) (P = 0.0610, P = 0.0004, respectively). We divided the Rb status into preserved expression (> 90%, n = 68), partial loss (PL) (10-90%, n = 97) and complete loss (CL) (< 10%, n = 12). Among the HPV-positive cases (n = 105), the Rb pattern was typically PL (n = 97, 92.4%) and rarely CL (n = 8, 7.6%), but never preserved expression (0%). In contrast, among the HPV-negative cases (n = 72), the Rb pattern was typically preserved expression (n = 68, 94.4%) and rarely CL (n = 4, 5.6%), but never PL (0%). Compared to p16 alone, the combination of p16 overexpression and Rb-PL/CL showed equally excellent sensitivity (each 100%) and improved specificity (97.2 versus 88.9%) and positive predictive values (98.1 versus 92.9%).

CONCLUSIONS

These results suggest that the combined use of p16 and Rb immunohistochemistry could be a reliable, cost-effective method to predict HR-HPV infection in OPSCCs; however, HPV specific testing is necessary on inconclusive cases. We propose a diagnostic algorithm for practical use of these markers.

Oropharyngeal Mixed Neuroendocrine-Nonneuroendocrine Neoplasm (MiNEN): A Case Report and Literature Review

Primary mixed neuroendocrine-nonneuroendocrine neoplasm (MiNEN) of the head and neck region is a rare biphasic tumor with an aggressive biological behavior. This report highlights an additional case of oropharyngeal MiNEN in a 46-year-old male patient with a previous long-term smoking history. Histologic evaluation revealed a biphasic tumor infiltrating the lamina propria. The first component consisted of a classic keratinizing squamous cell carcinoma. The second component consisted of small-to-intermediate sized cells with neuroendocrine features. Synaptophysin and CD56 immunohistochemical stains confirmed neuroendocrine lineage in this component. The presence of two morphological components with neuroendocrine and nonneuroendocrine features on histologic assessment should alert the pathologist to consider a MiNEN in their case work-up.

Genomics of High-Grade Neuroendocrine Neoplasms: Well-Differentiated Neuroendocrine Tumor with High-Grade Features (G3 NET) and Neuroendocrine Carcinomas (NEC) of Various Anatomic Sites

High-grade neuroendocrine neoplasms (HG-NENs) are clinically aggressive diseases, the classification of which has recently been redefined. They now include both poorly differentiated NENs (neuroendocrine carcinoma, NECs) and high proliferating well-differentiated NENs (called grade 3 neuroendocrine tumors, G3 NETs, in the digestive system). In the last decade, the "molecular revolution" that has affected all fields of medical oncology has also shed light in the understanding of HG NENs heterogeneity and has provided new diagnostic and therapeutic tools, useful in the management of these malignancies. Considering the kaleidoscopic aspects of HG NENs in various anatomical sites, this review systematically addresses the genomic landscape of such neoplasm throughout the more common thoracic and digestive locations, as well as it will consider other rare but not exceptional primary sites, including the skin, the head and neck, and the urogenital system. The revision of the available literature will then be oriented to understand the translational relevance of molecular data, by analyzing conceptual issues, clinicopathological correlations, and unmet needs in this field.

[Primary small cell neuroendocrine carcinoma of the larynx: a review of literature and case series]

INTRODUCTION

 Small cell neuroendocrine carcinoma (SCNC) of the larynx is a rare tumor entity with a 5-year overall survival (OS) of only 5 % after treatment with chemoradiotherapy.

METHODS

 A systematic review of the literature was performed for "SCNC" and "SCNC in head and neck". Our hospital's own electronic patient file database was investigated for patients diagnosed with a SCNC over the last 12 years.

RESULTS

 The effectiveness of chemoradiotherapy in SCNC is still unclear since randomized clinical trials are missing for the evaluation of standard of care treatment. Common therapy approaches are based on experiences with small cell lung cancer. 0.5 % of all SCNC occur in the head and neck region. In the last 12 years, we diagnosed 9 patients with SCNC, two of which were located in the larynx. Exemplarily, we report the case of a 29-year-old male with the initial diagnosis of a SCNC of the larynx with concurrent lymph node metastasis. This case is particularly interesting due to the young age at disease onset and the lack of major risk factors. Treatment was modified to nivolumab due to progressive disease after treatment with chemoradiotherapy. After an OS of 22 months, the patient deceased due to a tumor-associated major bleeding with airway obstruction.

CONCLUSION

 So far there are no clinical reports evaluating the use of nivolumab in third-line-therapy of SCNC. NTRK fusion (neurotrophic tyrosine receptor kinase gene fusion) or the folate receptor expression analysis should be considered to evaluate the potential use of a tropomyosin receptor kinase inhibitor or a folate receptor targeting therapy.

Clinicopathological and genomic features in patients with head and neck neuroendocrine carcinoma

Neuroendocrine carcinoma (NEC) of the head and neck is a rare type of malignancy, accounting for only 0.3% of all head and neck cancers, and its clinicopathological and genomic features have not been fully characterized. We conducted a retrospective analysis of 27 patients with poorly differentiated NEC of the head and neck seen at our institution over a period of 15 years. Patient characteristics, adopted therapies, and clinical outcomes were reviewed based on the medical records. Pathological analysis and targeted sequencing of 523 cancer-related genes were performed using evaluable biopsied/resected specimens based on the clinical data. The most common tumor locations were the paranasal sinus (33%) and the oropharynx (19%). Eighty-one percent of the patients had locally advanced disease. The 3-year overall survival rates in all patients and in the 17 patients with locally advanced disease who received multimodal curative treatments were 39% and 53%, respectively. Histologically, large cell neuroendocrine carcinoma was the predominant subtype (58% of evaluable cases), and the Ki-67 labeling index ranged from 59 to 99% (median: 85%). Next-generation sequencing in 14 patients identified pathogenic/likely pathogenic variants in TP53, RB1, PIK3CA-related genes (PREX2, PIK3CA, and PTEN), NOTCH1, and SMARCA4 in six (43%), three (21%), two (14%), two (14%), and one (7%) patients, respectively. Sequencing also detected the FGFR3-TACC3 fusion gene in one patient. The median value of the total mutational burden (TMB) was 7.1/Mb, and three patients had TMB ≥ 10. Regardless of the aggressive pathological features, our data revealed favorable clinical characteristics in the patients with locally advanced disease who received curative treatment. The lower TP53 and RB1 mutation prevalence rates compared to those described for small cell lung cancer suggests the biological heterogeneity of NEC in different parts of the body. Furthermore, the FGFR3-TACC3 fusion gene and mutations in genes encoding the components of the NOTCH and PI3K/AKT/mTOR pathways found in our study may be promising targets for NEC of the head and neck.

Pelvic and Ovarian Recurrence of Small HPV-associated Cervical Adenocarcinoma With Transformation to Neuroendocrine Carcinoma

The phenomenon of small human papillomavirus-associated cervical adenocarcinomas involving the ovary via a transuterine and transtubal route is uncommon but well described in the literature. We report a unique case of a small human papillomavirus-associated cervical adenocarcinoma spreading to both ovaries and the pelvis via this route 22 mo after loop excision and trachelectomy and developing into a high-grade neuroendocrine carcinoma in the metastasis.

Pathology of HPV-Associated Head and Neck Carcinomas: Recent Data and Perspectives for the Development of Specific Tumor Markers

A significant subset of carcinomas developed in the head and neck (H&NCs) are associated with specific human papillomaviruses (HPV) genotypes. In particular, 40–60% of oropharyngeal carcinoma cases are linked to HPV. Epidemiological studies have demonstrated that HPV oral infections are predominantly sexually transmitted and are more frequent among men (10–18%) than women (3.6–8.8%). Although there is a large diversity of HPV genotypes associated with H&NCs, HPV16 lineage represents 83% of the reported cases. The prognostic value of HPV as a biological parameter is well recognized. However, the use of HPV DNA as a diagnostic and/or predictive marker is not fully developed. Recent data reporting the physical state of the HPV genome in tumors have shown that HPV DNA integration into the tumor cell genome could lead to the alteration of cellular genes implicated in oncogenesis. Most importantly, HPV DNA corresponds to a tumor marker that can be detected in the blood of patients. Profile of the HPV DNA molecular patterns in tumor cells using New Genome Sequencing-based technologies, allows the identification of highly specific tumor markers valuable for the development of innovative diagnostic and therapeutic approaches. This review will summarize recent epidemiological data concerning HPV-associated H&NCs, the genomic characterization of these tumors, including the presence of HPV DNA in tumor cells, and will propose perspectives for developing improved care of patients with HPV-associated H&NCs, based on the use of viral sequences as personalized tumor markers and, over the longer term, as a therapeutic target.

ICAR: endoscopic skull-base surgery

BACKGROUND

Endoscopic skull-base surgery (ESBS) is employed in the management of diverse skull-base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull-base surgery have produced the International Consensus Statement on Endoscopic Skull-Base Surgery (ICAR:ESBS).

METHODS

Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence-based review or evidence-based review with recommendations format. Subsequently, each topic was written and then reviewed by skull-base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull-base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated.

CONCLUSION

A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence-based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull-base community to embrace these opportunities and collaboratively address these shortcomings.

Neuroendocrine Carcinoma of the Uterine Cervix: A Clinicopathologic and Immunohistochemical Study with Focus on Novel Markers (Sst2-Sst5)

BACKGROUND

Gynecological neuroendocrine neoplasms (NENs) are extremely rare, accounting for 1.2-2.4% of the NENs. The aim of this study was to test cervical NENs for novel markers of potential utility for differential diagnosis and target therapy.

METHODS

All cases of our center (n = 16) were retrieved and tested by immunohistochemistry (IHC) for 12 markers including markers of neuroendocrine differentiation (chromogranin A, synaptophysin, CD56), transcription factors (CDX2 and TTF1), proteins p40, p63, p16INK4a, and p53, somatostatin receptors subtypes (SST2-SST5) and the proliferation marker Ki67 (MIB1).

RESULTS

All cases were poorly differentiated neuroendocrine carcinomas (NECs), 10 small cell types (small cell-neuroendocrine carcinomas, SCNECs) and 6 large cell types (large cell-neuroendocrine carcinomas, LCNECs); in 3 cases a predominant associated adenocarcinoma component was observed. Neuroendocrine cancer cells expressed at least 2 of the 3 tested neuroendocrine markers; p16 was intensely expressed in 14 (87.5%) cases; SST5 in 11 (56.25%, score 2-3, in 9 cases); SST2 in 8 (50%, score 2-3 in 8), CDX2 in 8 (50%), TTF1 in 5 (31.25%), and p53 in 1 case (0.06%). P63 and p40 expressions were negative, with the exception of one case that showed moderate expression for p63.

CONCLUSIONS

P40 is a more useful marker for the differential diagnosis compared to squamous cell carcinoma. Neither CDX2 nor TTF1 expression may help the differential diagnosis versus potential cervical metastasis. P16 expression may suggest a cervical origin of NEC; however, it must be always integrated by clinical and instrumental data. The expression of SST2 and SST5 could support a role for SSAs (Somatostatin Analogues) in the diagnosis and therapy of patients with cervical NECs.

An Algorithmic Immunohistochemical Approach to Define Tumor Type and Assign Site of Origin

Immunohistochemistry represents an indispensable complement to an epidemiology and morphology-driven approach to tumor diagnosis and site of origin assignment. This review reflects the state of my current practice, based on 15-years' experience in Pathology and a deep-dive into the literature, always striving to be better equipped to answer the age old questions, "What is it, and where is it from?" The tables and figures in this manuscript are the ones I "pull up on the computer" when I am teaching at the microscope and turn to myself when I am (frequently) stuck. This field is so exciting because I firmly believe that, through the application of next-generation immunohistochemistry, we can provide better answers than ever before. Specific topics covered in this review include (1) broad tumor classification and associated screening markers; (2) the role of cancer epidemiology in determining pretest probability; (3) broad-spectrum epithelial markers; (4) noncanonical expression of broad tumor class screening markers; (5) a morphologic pattern-based approach to poorly to undifferentiated malignant neoplasms; (6) a morphologic and immunohistochemical approach to define 4 main carcinoma types; (7) CK7/CK20 coordinate expression; (8) added value of semiquantitative immunohistochemical stain assessment; algorithmic immunohistochemical approaches to (9) "garden variety" adenocarcinomas presenting in the liver, (10) large polygonal cell adenocarcinomas, (11) the distinction of primary surface ovarian epithelial tumors with mucinous features from metastasis, (12) tumors presenting at alternative anatomic sites, (13) squamous cell carcinoma versus urothelial carcinoma, and neuroendocrine neoplasms, including (14) the distinction of pheochromocytoma/paraganglioma from well-differentiated neuroendocrine tumor, site of origin assignment in (15) well-differentiated neuroendocrine tumor and (16) poorly differentiated neuroendocrine carcinoma, and (17) the distinction of well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma; it concludes with (18) a discussion of diagnostic considerations in the broad-spectrum keratin/CD45/S-100-"triple-negative" neoplasm.

Clinico-pathological peculiarities of human papilloma virus driven head and neck squamous cell carcinoma: A comprehensive update

AIMS

The current article provides a detailed account of the current understanding of molecular and clinico-pathological aspects of Human papilloma virus (HPV) driven head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

The literature review included most of the landmark trials and clinical studies related to the HPV driven HNSCC.

KEY FINDINGS

HPV positive HNSCC differ distinctly from HPV negative tobacco-related HNSCC, especially in oropharyngeal region. Therefore, the American joint committee on cancer`s latest manual for classification and staging of cancer suggests a separate staging system for HPV positive oropharyngeal cancers. Despite the younger patients being affected and the high propensity for cervical metastasis, the HPV positive oropharyngeal cancers respond much better to the treatment. The association with wild type TP53 and low EGFR expression confers the favorable prognosis in HPV driven HNSCC. Since the association is not universal, we suggest checking for p53 and EGFR expression status before considering de-intensification of therapy. In addition, the presence of matted lymph nodes and five or more nodes could mean relatively poorer prognosis, and are not suitable for de-intensification of therapy. The same is also true probably with higher T stage and co-existing tobacco use. The methods for the detection of p16, HPV DNA, HPV E6/E7 mRNA, anti-E6/E7 antibodies, in tissue, in serum and in saliva of patients, along with their clinical implications are also discussed.

SIGNIFICANCE

This article provides latest developments on the HPV driven HNSCC. 'Diagnosis of transcriptionally active HPV infection,' 'Modalities for surveillance,' 'Implication of de-escalation of therapy' are some of the critical issues that could serve the medical, the research as well as the patient communities.

Human papilloma virus related squamous cell carcinomas of the head and neck: diagnosis, clinical implications and detection of HPV

High-risk human papillomavirus (HPV) positive squamous cell carcinoma (SCC) of the head and neck is reported most commonly in the oropharynx but can also uncommonly be found in other sites such as the anterior oral cavity and sinonasal tract. While HPV positive oropharyngeal squamous cell carcinoma (HPV-OPSCC) has been shown to have a more favourable prognosis than conventional smoking- and alcohol-related anterior oral cavity squamous cell carcinoma (OSCC), HPV positive SCC arising elsewhere in the head and neck region does not carry the same favourable prognosis. HPV-OPSCC often tends to present with large cystic metastases in the cervical lymph nodes, with a clinically and radiologically occult primary. Correct diagnosis of the initial biopsy/cytology specimen is critical for directing further investigations and management. In recognition of its distinct biological behaviour, the 8th edition of the American Joint Commission on Cancer (AJCC 8) has proposed a separate clinical and pathological staging system for HPV-OPSCC compared to that for a conventional primary OSCC or neck metastasis of similar size. The new AJCC staging does not apply to other HPV positive SCC of the head and neck. This review examines the current biology of HPV positive SCC, focusing on HPV-OPSCC. The value and pitfalls of current detection methods of HPV are discussed with an emphasis on the role of the pathologist in the diagnosis and management of HPV positive SCC of the head and neck.

Update on Neuroendocrine Carcinomas of the Larynx

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

High-Grade Neuroendocrine Carcinoma of the Head and Neck: Human Papillomavirus Status and PD-L1 Expression

BACKGROUND

Human papillomavirus (HPV)-related head and neck squamous cell carcinoma represents an important subgroup of head and neck cancer, but HPV occurs also in the less common neuroendocrine carcinomas (NEC). The PD-1/PD-L1 pathway appears to be activated in pulmonary NEC and correlates with a higher mutation burden, but the potential of NEC to respond to checkpoint inhibitors is unknown to a large extent.

OBJECTIVES

To determine the HPV status of NEC of the head and neck region and to investigate the expression of PD-1 and its ligands PD-L1 and PD-L2.

METHODS

Surgical tumor samples from 2006 to 2017 were analyzed. HPV status was determined by p16 immunohistochemistry (IHC) and multiplex PCR. IHC using the Cologne Score was performed for PD-1, PD-L1, and PD-L2.

RESULTS

Seven NEC tumor samples were analyzed, three of them showed HPV type 18. Expression of PD-1 and PD-L1 differed widely and showed no correlation to HPV status. IHC showed an overexpression of PD-L2 in most of the patients.

CONCLUSIONS AND SIGNIFICANCE

A multicentric analysis of NEC is needed to further evaluate the role of HPV as well as immunocheckpoints with regard to inflammatory immune response in genesis and clinical course of this rare tumor entity. Biomarkers for selection of novel treatment regimens, including immunotherapeutic approaches, are warranted.

Heterogeneity of p16 immunohistochemistry and increased sensitivity of RNA in situ hybridization in cytology specimens of HPV-related head and neck squamous cell carcinoma

BACKGROUND

Many patients with human papillomavirus (HPV)-related head and neck squamous cell carcinoma (HPV-HNSCC) initially present with cervical lymph node metastases. Although p16 immunohistochemistry (IHC) is the most commonly used surrogate marker for HPV, however criteria in cytologic material are not well established. The objective of this study was to better characterize p16 IHC in cell blocks of metastatic HPV-HNSCC, and to evaluate the performance of HPV RNA in situ hybridization (RNA ISH).

METHODS

p16 IHC was performed on cell blocks from 97 metastatic HPV-HNSCC fine-needle aspiration specimens with HPV status confirmed by DNA or RNA ISH or polymerase chain reaction (PCR). Tumor cellularity (<100 cells, 100-500 cells, and >500 cells) and quality (presence of cell clusters, necrosis) were recorded. p16 staining intensity and extent (1%-9%, 10%-69%, and ≥70%) were scored. In addition, RNA ISH was performed on 38 PCR-positive cases.

RESULTS

p16 IHC was positive in 90 of 97 cases (93%), demonstrating variable patterns. p16 staining was found to be moderate to strong in 69 cases, with 37 cases (38%) demonstrating positivity in ≥70% of tumor cells. Weak staining occurred in 21 cases (22%) and 7 cases (7%) were negative. Of the 60 cases with weak and/or absent expression or staining in <70% of cells, 30 cases (50%) had <100 tumor cells, 12 (20%) lacked cell clusters, and 19 cases (32%) had extensive necrosis. RNA ISH was positive in 37 of 38 cases (97%) that were HPV positive by PCR.

CONCLUSIONS

p16 is heterogeneous in cell blocks of metastatic HPV-HNSCC, suggesting that any p16 positivity should prompt confirmatory HPV studies. RNA ISH appears to demonstrate high sensitivity, and laboratories even may consider using RNA ISH as a first-line HPV test in cytologic specimens.

Human Papillomavirus-Associated Oropharyngeal High-Grade Neuroendocrine Carcinoma in an Adolescent: Case Report and Review of Literature

Oropharyngeal small cell carcinomas (OPSmCC) are rare with only few case reports and case series published in the literature. More recently, an association of these tumors with human papillomavirus (HPV) infection has been detected. However, unlike oropharyngeal squamous cell carcinomas which have a better outcome when associated with HPV, OPSmCC exhibit an aggressive behavior. In this article, we report a case of tonsillar carcinoma arising in a 14-year-old boy that was associated with HPV infection. The tumor exhibited morphologic features of small cell carcinoma with no overt squamous differentiation. Yet, by immunohistochemistry, it showed diffuse and strong co-expression of both squamous and neuroendocrine markers. In addition, we present the clinicopathologic features of all the cases of OPSmCC reported in the literature for which p16 and/or HPV testing have been done.

Poorly differentiated neuroendocrine carcinoma of the head and neck: human papillomavirus tumour status/p16 status and impact on overall survival

AIMS

Poorly differentiated neuroendocrine carcinoma (PDNEC) of the head and neck is a rare high-grade neuroendocrine neoplasm. Human papillomavirus (HPV) status and p16 status are as yet unclear among PDNECs, owing to a lack of statistical analysis. The objective of the present study was therefore to evaluate their potential clinicopathological associations, and their prognostic impact on overall survival in PDNECs of the head and neck, regardless to HPV genotype.

METHODS AND RESULTS

All cases of PDNEC of the head and neck between 1998 and 2019 were identified from the database of the Lyon university hospital pathology department (n = 21); for these cases, p16 immunohistochemistry and HPV in-situ hybridisation were performed. Published cases of PDNEC of the head and neck with assessment of HPV status and p16 status were identified in PubMed (n = 57). Local and published cases were pooled for analysis. HPV positive (HPV+) tumour status was found to be significantly associated with oropharyngeal localisation (P < 0.001) and overexpression of p16 (P < 0.001). Multivariate analysis, adjusted on tumour site, histological subtype, p16 status, HPV status, and source of the case, showed that oropharyngeal localisation [hazard ratio (HR) 3.031, 95% confidence interval (CI) 1.257-7.310] and being a small-cell variant (HR 2.859, 95% CI 1.150-7.109) were significant predictors of worse overall survival; HPV+ tumour status was associated with better overall survival (HR 0.388, 95% CI 0.146-0.995).

CONCLUSIONS

HPV+ tumour status was associated with oropharyngeal PDNECs and with a better prognosis.

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

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

Small Cell and Squamous Cell Carcinomas of the Head and Neck: Comparing Incidence and Survival Trends Based on Surveillance, Epidemiology, and End Results (SEER) Data

BACKGROUND

Small cell carcinomas of the head and neck (SmCCHNs) are rare neoplasms with an unfavorable prognosis. Population-based data describing survival and prognostic factors for SmCCHN are limited.

METHODS

Data were obtained from the U.S. National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database for 1973-2013. Patient and tumor-related characteristics for SmCCHN were compared with those for squamous cell carcinoma of the head and neck (SCCHN). Survival was compared by constructing Kaplan-Meier curves and Cox proportional hazard models with and without propensity score matching.

RESULTS

The data set included 609 SmCCHN and 227,943 SCCHN cases. Both histological subtypes were more common in men than women and more common in white patients. SmCCHN was most likely to originate in the larynx, glottis and hypopharynx, or salivary glands and to present with more advanced stage and grade. SCCHN was most likely to originate in the oral cavity and was found infrequently in the salivary glands. Overall 5- and 10-year survival estimates were 27% and 18% for SmCCHN and 46% and 31% for SCCHN, respectively. In multivariable survival analyses adjusting for age, sex, race, marital status, year of diagnosis, stage, grade, and receipt of radiation, the hazard ratio (HR) comparing SmCCHN with SCCHN was 1.53 with a 95% confidence interval (CI) from 1.39 to 1.68. Average 5-year survival varied widely between the histologic types when comparing tumor sites: 14.5% for SmCCHN versus 48.9% for SCCHN in the oropharynx. In propensity score matched analyses, the corresponding HR was 1.27 (95% CI, 1.15-1.40).

CONCLUSION

Compared with SCCHN, SmCCHN carries a worse survival and is more likely to present with more advanced stage.

IMPLICATIONS FOR PRACTICE

Small cell carcinoma of the head and neck (SmCCHN) is a rare subtype of head and neck cancer. In this Surveillance, Epidemiology, and End Results (SEER) data analysis, the characteristics and survival of SmCCHN are compared with those of the common squamous cell carcinoma of the head and neck. Results show that SmCCHN carries a worse prognosis and tends to present at a more advanced stage; SmCCHN also is ten times more likely to originate from the salivary glands. These findings may have implications for clinical practice, as location of the tumor may strongly associate with the pathologic diagnosis. If a SmCCHN is diagnosed, a disseminated disease is likely; hence vigilance in staging procedures is indicated.

Seed and soil? - Pharyngeal Merkel cell carcinoma after radiotherapy for laryngeal squamous cell carcinoma

Merkel cell carcinoma (MCC) is a neuroendocrine cutaneous malignancy that may present as metastatic disease without a known primary site but, most commonly originates in the sun-exposed skin of the head, neck, and extremities. We present a 66-year-old male treated with chemo-radiation for T3N2cM0 laryngeal squamous cell carcinoma (SCCa) six years before he was diagnosed with MCC isolated to the radiated laryngopharynx. Mucosal MCC is rare and radiation-induced MCC has been hypothesized to occur in previously radiated tissue but, never before to the laryngopharynx. Implications regarding cancer biology and management is focused with discussion on relevant advances in pathologic assessment and immunotherapy.

Cytopathologic characteristics of HPV-related small cell carcinoma of the oropharynx

BACKGROUND

Human papillomavirus (HPV)-related squamous cell carcinoma (SqCC) of the oropharynx is an epidemiologically and clinically distinct form of SqCC that is associated with an improved prognosis. However, HPV-related small cell carcinoma of the oropharynx is a rare and newly described variant that is associated with aggressive clinical behavior and poor outcomes. To date, fewer than 2 dozen reports of this entity exist in the literature, and there is no discussion of cytopathologic features. This article reports 6 cases and discusses the salient cytomorphologic findings, ancillary studies, and challenges when this entity is encountered.

METHODS

Anatomic pathology archives were searched to identify patients with a diagnosis of HPV-related small cell carcinoma of the oropharynx. Medical records were reviewed to document the following: age, sex, smoking status, other relevant clinical history, primary location, treatment, and clinical outcome. Both p16 and high-risk HPV in situ hybridization (ISH) studies were positive in at least 1 specimen from each patient. The pathologic diagnoses, cytomorphologic characteristics, immunocytochemical stains, and HPV ISH studies were reviewed and recorded for all available cases.

RESULTS

Six patients with 11 cytopathology specimens of HPV-related small cell carcinoma of the oropharynx were identified. The mean age was 61.3 years, and all patients died with widely metastatic disease (mean, 23 months; range, 12-48 months). Mixed small cell carcinoma and SqCC components were present in half of the cases.

CONCLUSIONS

The identification of a small cell component can be reliably performed with cytology preparations and is crucial because this (and not the HPV status) determines the prognosis.

How phenotype guides management of the neuroendocrine carcinomas of the larynx

Objective

This review aimed to critically analyse data pertaining to the clinical presentation and treatment of neuroendocrine carcinomas of the larynx.

Method

A PubMed search was performed using the term ‘neuroendocrine carcinoma’. English-language articles on neuroendocrine carcinoma of the larynx were reviewed in detail.

Results and conclusion

While many historical classifications have been proposed, in contemporary practice these tumours are sub-classified into four subtypes: carcinoid, atypical carcinoid, small cell neuroendocrine carcinoma and large cell neuroendocrine carcinoma. These tumours exhibit a wide range of biological behaviour, ranging from the extremely aggressive nature of small and large cell neuroendocrine carcinomas, which usually have a fatal prognosis, to the less aggressive course of carcinoid tumours. In small and large cell neuroendocrine carcinomas, a combination of irradiation and chemotherapy is indicated, while carcinoid and atypical carcinoid tumour management entails conservation surgery.

Pathology of Neuroendocrine Tumours of the Female Genital Tract

Neuroendocrine tumours are uncommon or rare at all sites in the female genital tract. The 2014 World Health Organisation (WHO) Classification of neuroendocrine tumours of the endometrium, cervix, vagina and vulva has been updated with adoption of the terms low-grade neuroendocrine tumour and high-grade neuroendocrine carcinoma. In the endometrium and cervix, high-grade neoplasms are much more prevalent than low-grade and are more common in the cervix than the corpus. In the ovary, low-grade tumours are more common than high-grade carcinomas and the term carcinoid tumour is still used in WHO 2014. The term ovarian small-cell carcinoma of pulmonary type is included in WHO 2014 for a tumour which in other organs is termed high small-cell neuroendocrine carcinoma. Neuroendocrine tumours at various sites within the female genital tract often occur in association with other neoplasms and more uncommonly in pure form.