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

EBV-positive small cell neuroendocrine carcinoma of nasopharynx as a probably unique subtype of neuroendocrine carcinoma: a clinicopathologic study of three cases and literature review

BACKGROUND

There is currently scarcity of information on small cell neuroendocrine carcinoma of the nasopharynx (SCNEC-nasopharynx). It is believed that this type of cancer is not associated with Epstein-Barr virus (EBV) infection and is indistinguishable from classic SCNEC occurring in other organs.

MATERIALS AND METHODS

Herein we provided 3 cases of nasopharyngeal mass in our hospital, two males and one female. On admission, these patients were considered nasopharyngeal carcinoma with lymph node metastasis, and one of them had liver metastasis. The nasopharyngeal mucosal tissues were biopsied for pathological examination including immunohistochemistry and in situ hybridization. PubMed database was searched for articles about SCNEC-nasopharynx published up to April 2024 in any language.

RESULT

The 3 cases had similar histological features of SCNEC in other organs but differed in rich- tumor-infiltrating lymphocytes (TILs). All of them stained for pancytokeratin (panCK) and epidermal growth factor receptor (EGFR). Case 1 and Case 2 diffusely expressed insulinoma-associated protein 1(INSM-1) and synaptophysin (Syn), Case 3 strongly stained for CD56 and Syn. Immunostaining of all 3 cases for p40, p63, TTF-1, CK20, S-100 and NUT showed negative. BRG-1, INI-1 and Rb were retained. And p53 all showed wild-type expression. The Ki-67 labeling indiced of case 1, 2, and 3 were 80%, 90%, and 80%, respectively. In situ hybridization showed strong and uniform nuclear positivity of EBV-encoded small RNAs (EBER) in the neoplastic cells of 3 cases.

CONCLUSION

EBV-positive SCNEC-nasopharynx was exactly rare. The origin of this tumor is still controversial. It may originate from EBV-infected mucosal epithelium like nasopharyngeal carcinoma. Based on our cases and relevant literature, we found EBV-positive SCNEC-nasopharynx as a probably site-specific subtype of SCNEC with differing pathogenetic mechanism. The subtype not only virus positivity but also that it was associated with TILs and did not show p53 or Rb alterations by immunohistochemistry. It may be more responsive to treatment and have a better prognosis than classic SCNEC. We will continue to follow-up these patients and collect additional cases to further understand the unique biology of this rare solid tumor.

Approach to small biopsies in the larynx

Small biopsies in the larynx can make a definitive diagnosis challenging due to the sampling or tangential sectioning. The differential diagnosis can be divided into mucosal lesions (squamous papillomas, intraepithelial dysplasia, and invasive squamous cell carcinoma) or submucosal lesions (vocal cord polyps/nodules, amyloidosis, granular cell tumor, rhabdomyoma, neuroendocrine neoplasms, salivary gland tumors, and cartilaginous tumors). Diagnostic criteria (both morphologic and immunohistochemical) are reviewed to arrive at a diagnosis even on small biopsy.

Top 10 Nested Pattern Head and Neck Lesions to Notice

BACKGROUND

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

METHODS

Review.

RESULTS

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

CONCLUSION

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

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.

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

Background

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

Methods

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

Results

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

Conclusions

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