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Schwannoma is a benign, slow growing, usually solitary and encapsulated tumor derived from Schwann cells of the nerve sheath. Schwannomas can be divided into central, or intraosseous, and peripheral lesions. The etiology is unknown, but it is postulated that lesions arise by the proliferation of Schwann cells at one point inside the perineurium. Schwannomas may mimic other diseases of the head and neck, such as infection, tumor or metastasis. Extracranial schwannomas are rare; in this study we review a series of 22 cases of schwannomas originating in the head and neck region over a period of eight years. All tumors were benign and well-encapsulated. Tumor size ranged from 0.5 to 9 cm. The age range of patients studied was 15–74 years with a mean age of 35 years and a male predilection (M:F, 2.6:1)was noted. Four cases of schwannomas occurred in the tongue (18.18%) and lower lip (18.18%), three in the nasal cavity (13.64%), two each (9.09%) in the buccal mucosa, parapharyngeal space (9.09%), and eyebrow (9.09%), and one each in the upper lip (4.55%), lateral canthus of the eye (4.55%), intraorbital region (4.55%), submandibular gland (4.55%), and ear (4.55%). Schwannomas can present in a wide variety of sites within the head and neck. The tumor is benign and tend to be asymptomatic for long periods of time. Histopathology is the gold standard for diagnosis. Our study describes the clinicopathologic features of extracranial head and neck schwannomas, highlights the histopathologic features, and discusses pertinent findings with correlation to the present literature. It is important that both clinicians and pathologists be familiar with the uncommon sites of occurrence and the potential pitfalls associated with the diagnosis and management of these tumors.

Background: Neuroendocrine differentiation in the prostate gland ranges from clinically insignificant neuroendocrine differentiation detected with markers in an otherwise conventional prostatic adenocarcinoma to a lethal high-grade small/large cell neuroendocrine carcinoma. The concept of neuroendocrine differentiation in prostatic adenocarcinoma has gained considerable importance due to its prognostic and therapeutic ramifications and pathologists play a pivotal role in its recognition. However, its awareness, reporting, and resource utilization practice patterns among pathologists are largely unknown. Methods: Representative examples of different spectrums of neuroendocrine differentiation along with a detailed questionnaire were shared among 39 urologic pathologists using the survey monkey software. Participants were specifically questioned about the use and awareness of the 2016 WHO classification of neuroendocrine tumors of the prostate, understanding of the clinical significance of each entity, and use of different immunohistochemical (IHC) markers. De-identified respondent data were analyzed. Results: A vast majority (90%) of the participants utilize IHC markers to confirm the diagnosis of small cell neuroendocrine carcinoma. A majority (87%) of the respondents were in agreement regarding the utilization of type of IHC markers for small cell neuroendocrine carcinoma for which 85% of the pathologists agreed that determination of the site of origin of a high-grade neuroendocrine carcinoma is not critical, as these are treated similarly. In the setting of mixed carcinomas, 62% of respondents indicated that they provide quantification and grading of the acinar component. There were varied responses regarding the prognostic implication of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and for Paneth cell-like differentiation. The classification of large cell neuroendocrine carcinoma was highly varied, with only 38% agreement in the illustrated case. Finally, despite the recommendation not to perform neuroendocrine markers in the absence of morphologic evidence of neuroendocrine differentiation, 62% would routinely utilize IHC in the work-up of a Gleason score 5 + 5 = 10 acinar adenocarcinoma and its differentiation from high-grade neuroendocrine carcinoma. Conclusion: There is a disparity in the practice utilization patterns among the urologic pathologists with regard to diagnosing high-grade neuroendocrine carcinoma and in understanding the clinical significance of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and Paneth cell-like neuroendocrine differentiation. There seems to have a trend towards overutilization of IHC to determine neuroendocrine differentiation in the absence of neuroendocrine features on morphology. The survey results suggest a need for further refinement and development of standardized guidelines for the classification and reporting of neuroendocrine differentiation in the prostate gland.