The Differential Diagnosis of Sinonasal/Nasopharyngeal Neuroendocrine/Neuroectodermally Derived Tumors

Primary Small Cell Neuroendocrine Carcinoma of nasopharynx with metastatic cervical lymph nodes: an exceedingly rare entity with review of literature

Small cell neuroendocrine carcinoma of nasopharynx is extremely rare and displays aggressive nature with a poor prognosis. Neuroendocrine tumours rarely arise from the head and neck region and pose a diagnostic and management challenge. In English literature, only 16 cases of primary small cell neuroendocrine carcinoma of nasopharynx have been reported so far; and to the best of our knowledge, this is the seventeenth case and second in the younger age group. Here, we report the case of an adolescent male patient who presented with nasal blockage, repeated episodes of epistaxis and neck swellings. After proper diagnostic workup, the diagnosis of small cell neuroendocrine carcinoma of nasopharynx was made. The patient was treated with chemotherapy, followed by radiotherapy. Imaging investigation executed after the end of the treatment exhibited complete remission of the disease. The patient is kept under active surveillance with no signs of relapse at present.

Challenging differential diagnoses in small biopsies from the sinonasal tract

Sinonasal biopsy specimens are a challenging area in anatomic pathology. The small, often fragmented or crushed nature of these biopsies can hinder morphologic assessment. Additionally, many of the tumors in this area are rare and share morphologic, and sometime immunophenotypic similarities. In many cases, immunohistochemistry is helpful if not necessary to reach a specific diagnosis. In other cases, a specific diagnosis is not possible and a differential diagnosis must be given on a biopsy specimen despite access to a well-equipped immunohistochemistry laboratory. This review article groups some of the more challenging entities in the sinonasal region based on morphologic patterns. These include low grade squamoid lesions such as sinonasal (Schneiderian) papilloma and DEK::AFF2 rearranged carcinoma, glandular neoplasms such as intestinal and non-intestinal type sinonasal adenocarcinoma, high-grade carcinomas such as HPV-related multiphenotypic sinonasal carcinoma, NUT carcinoma and SWI/SNF deficient carcinomas, small round blue cell tumors such as teratocarcinosarcoma, neuroendocrine carcinoma and olfactory neuroblastoma, and finally, low grade spindle cell neoplasms such as glomangiopericytoma, biphenotypic sinonasal sarcoma and solitary fibrous tumor.

Ultrastructural and clinical features of central nervous system melanoma:Analysis of nine cases

To investigate the ultrastructural and clinical characteristics of melanoma of the central nervous system (CNS). The clinical and electron microscopy pathology data of nine patients with melanoma surveyed from 1993 to 2017 were analyzed. All the CNS melanomas were confirmed by transmission electron microscopy (TEM), including eight cases of primary melanomas and one case of metastatic melanoma. In this study, four stage II melanosomes were intracranial space-occupying, three of which were malignant melanoma, the other one was melanoma. Among the five stage IV melanosomes, four cases were intraspinal space-occupying, the other one was intracranial space-occupying, and the pathological diagnoses were all melanoma. At present, TEM is an important tool for the diagnosis of CNS melanomas. Malignant melanoma has high malignancy and recurrence rate and poor prognosis, while benign melanoma with relatively low recurrence rate, so we speculate that patients with mainly immature melanosomes are more likely to exhibit recurrence.

Neuroendocrine differentiation in a large series of genetically-confirmed Ewing's sarcoma family tumor: Does it provide any diagnostic or prognostic information?

Given the potential for neuroendocrine differentiation in Ewing's sarcoma family of tumors (ESFT), we aimed to determine neuroendocrine expression in a large series of genetically-confirmed ESFT and its prognostic significance in clinically-localised neoplasms (n = 176). Slides prepared from tissue microarrays were stained for Insulinoma-associated protein 1 (INSM1), CD56, chromogranin-A and synaptophysin. INSM1 expression was present in 59% of ESFT, while synaptophysin, chromogranin-A and CD56 were expressed in only 13%, 8% and 5% of ESFT, respectively. Histological subtypes were only significantly correlated with INSM1 (p = 0.032) or CD56 (p = 0.016) immunoexpression. Regarding prognosis, no significant association was found between INSM1, synaptophysin or chromogranin-A immunoexpression and progression-free survival (PFS) or overall survival (OS). Despite the low proportion of tumors with CD56 immunoreactivity, CD56 expression was shown to correlate with both poor PFS (p < 0.001) and poor OS (p < 0.001) in the present series. In conclusion, neuroendocrine differentiation is often present in ESFT, and in the present study INSM1 expression in particular was found to be higher than previously described in Ewing's tumors. Nevertheless, this finding does not distinguish these tumors from other round cell tumors that may show focal or diffuse neuroendocrine differentiation. CD56 expression could be used as a prognostic factor in ESFT, although given the results herein obtained, we recommend a prospective validation in independent series including localized and disseminated tumors in ESFT.

Clinical outcomes, ultrastructure and immunohistochemical features of canine high-grade olfactory neuroblastoma

Olfactory neuroblastoma (ONB) is a rare intranasal neoplasm in both dogs and humans. Similar clinical presentation and overlapping histologic and immunohistochemical features of ONB with other intranasal neoplasms can make diagnosis and treatment of intranasal neoplasia challenging. Furthermore, in part because of their rarity, there is a lack of reporting on therapeutic regimen for these neoplasms. In humans, initial debulking surgery is usually followed by radiation therapy. Here we report on the histologic, immunohistochemical, and ultrastructural characteristics of canine ONB and report on the clinical progression of cases treated with radiation therapy. In all nine canine ONB examined here, neoplastic cells were arranged in a lobular manner amidst a prominent neurofibrillary matrix and had features consistent with Grade III (high grade) ONB. The neoplastic cells demonstrated positive immunohistochemical staining for TuJ-1, a Class III beta-tubulin neuronal cytoskeletal protein, and variable staining for other markers, including chromogranin, synaptophysin, AE1/AE3 and MAP2. The longest surviving case was treated with a regimen similar to that used in humans, consisting of debulking surgery followed by definitive radiation therapy. Our study found that TuJ-1 is a useful marker for ONB and that radiation therapy, even in cases of advanced disease, may result in prolonged survival.

DNA methylation-based reclassification of olfactory neuroblastoma

Olfactory neuroblastoma/esthesioneuroblastoma (ONB) is an uncommon neuroectodermal neoplasm thought to arise from the olfactory epithelium. Little is known about its molecular pathogenesis. For this study, a retrospective cohort of n = 66 tumor samples with the institutional diagnosis of ONB was analyzed by immunohistochemistry, genome-wide DNA methylation profiling, copy number analysis, and in a subset, next-generation panel sequencing of 560 tumor-associated genes. DNA methylation profiles were compared to those of relevant differential diagnoses of ONB. Unsupervised hierarchical clustering analysis of DNA methylation data revealed four subgroups among institutionally diagnosed ONB. The largest group (n = 42, 64%, Core ONB) presented with classical ONB histology and no overlap with other classes upon methylation profiling-based t-distributed stochastic neighbor embedding (t-SNE) analysis. A second DNA methylation group (n = 7, 11%) with CpG island methylator phenotype (CIMP) consisted of cases with strong expression of cytokeratin, no or scarce chromogranin A expression and IDH2 hotspot mutation in all cases. T-SNE analysis clustered these cases together with sinonasal carcinoma with IDH2 mutation. Four cases (6%) formed a small group characterized by an overall high level of DNA methylation, but without CIMP. The fourth group consisted of 13 cases that had heterogeneous DNA methylation profiles and strong cytokeratin expression in most cases. In t-SNE analysis, these cases mostly grouped among sinonasal adenocarcinoma, squamous cell carcinoma, and undifferentiated carcinoma. Copy number analysis indicated highly recurrent chromosomal changes among Core ONB with a high frequency of combined loss of chromosome 1-4, 8-10, and 12. NGS sequencing did not reveal highly recurrent mutations in ONB, with the only recurrently mutated genes being TP53 and DNMT3A. In conclusion, we demonstrate that institutionally diagnosed ONB are a heterogeneous group of tumors. Expression of cytokeratin, chromogranin A, the mutational status of IDH2 as well as DNA methylation patterns may greatly aid in the precise classification of ONB.

Undifferentiated sinonasal malignant melanoma: A case report

Undifferentiated sinonasal malignant melanoma (MM) is a rare type of tumor, which can be easily misdiagnosed. The present study reports a 41-year-old male patient who presented with a 4-day history of epistaxis. Clinical examination and radiological imaging lead to the detection of a mass in the right sinonasal region. Histopathological examination revealed that the mass was composed of malignant epithelioid cells arranged in nests and sheets. These cells displayed a hemangiopericytoma-like pattern with antler-like branching vessels. Immunohistochemical staining revealed that the tumor cells exhibited negative expression of melanocytic markers. This increased the difficulty of distinguishing undifferentiated MM from other malignant tumors located in the sinonasal area, particularly undifferentiated nasopharyngeal carcinoma. The diagnosis of undifferentiated MM was determined by ultrastructures, including the mature melanosomes and premelanosomes, in tumor cells by transmission electron microscopy. The present study suggests that the analysis of cancer stem cell marker and vasculogenic mimicry may be an important auxiliary tool for the diagnosis of MM.

Small cell neuroendocrine carcinoma of the nasopharynx: a rare case report

Small cell neuroendocrine carcinoma rarely appears primarily in the head and neck and exhibits aggressive behavior with a poor prognosis. The pathologist has a significant role in the diagnosis, and a consensual treatment still does not exist. The authors report the case of a middle-aged male patient who presented repeated episodes of massive epistaxis. The diagnostic work-up disclosed the diagnosis of small cell neuroendocrine carcinoma of the nasopharynx. The patient was treated with chemotherapy followed by radiotherapy. Imaging examinations performed after the end of treatment showed apparent complete remission of the disease. The patient was kept under active surveillance with no signs of local relapse or distant metastasis after 4 years of follow-up.

Sinonasal Small Round Blue Cell Tumors: An Immunohistochemical Approach

Although clinical history and morphologic appearance should be the initial considerations when evaluating small round blue cell tumors of the sinonasal tract, the final diagnosis often hinges on immunohistochemical findings. Unfortunately, interpretation of stains in these tumors is fraught with numerous pitfalls and limitations. This article presents an approach to sinonasal small round blue cell tumors based on four common immunohistochemical patterns: cytokeratin positivity, squamous marker positivity, neuroendocrine marker positivity, and cytokeratin negativity.

Sinonasal Carcinomas with Neuroendocrine Features: Histopathological Differentiation and Treatment Outcomes

Objectives Sinonasal cancers with neuroendocrine features share similar clinical, radiological, and histopathological features; however, these tumors often exhibit varying degrees of aggressive behavior presenting significant treatment challenges. The objective of this study was to report our experience with these rare malignancies and to present a review of current literature. Methods Following institutional review board approval, the records of all patients with biopsy-proven sinonasal malignancies over a 5-year period were reviewed. Results The study included 14 patients with olfactory neuroblastomas (ONBs), 7 patients with sinonasal undifferentiated carcinomas (SNUC), and 2 patients with sinonasal neuroendocrine carcinomas (SNEC). Histopathologic markers aided in final diagnosis, but showed variable specificity. In patients with sufficient follow-up, the 2-year disease-free survival rate was 81% (9/11) for ONB and 75% (3/4) for SNUC. Three patients developed a regional or distant recurrence (two with ONBs and one with SNUC). Two patients, one with SNEC and one with ONB, succumbed to brain radionecrosis related to proton radiation therapy. Conclusions Overlapping clinical and histopathological features in poorly differentiated sinonasal cancers with neuroendocrine features continue to present a diagnostic challenge. Individualized assessment and treatment strategies can improve the accuracy of the initial assessment and the treatment outcomes.