Neuroendocrine cells and associated malignancies of the oral mucosa: a review

A primary small cell neuroendocrine carcinoma (SCNC) of the oral cavity (cheek mucosa): Description of a case report

BACKGROUND

Small cell neuroendocrine carcinoma (SCNC) of the oral cavity is a poorly differentiated, high-grade and very aggressive tumor with a poor prognosis.

CASE DESCRIPTION

A 64-year-old, Caucasian, smoker man consulted for an ulcero-necrotic, exophytic, lesion of the right retromolar trigone. Haed&neck CT scan showed a right tonsillar tumor lesion. The ¹⁸F-PET scan confirmed the presence of a right, highly hypermetabolic tonsillar lesion and two homolateral, cervical lymph nodes. Histology and immunohistochemistry were consisted with the diagnosis of a primary SCNC of the oral cavity. As the tumor was locally advanced and unresectable, the patient underwent a definitive radio-chemotherapy with a cisplatin/etoposide combined regimen (4 cycles). The treatment was well tolerated and led to a complete tumor response.

CONCLUSION

The particularity of this case relies on the rarity of the oral SCNC, its difficult and challenging diagnosis, and the complexity of its management that is not validated by large clinical trials, data being extrapolated from small cell lung cancer. In our case, the patient presenting a locally advanced tumor was treated by a combined radio-chemiotherapy leading to a complete tumor regression. The patient's follow up is too short to assess the real benefit of this treatment on overall survival.

Merkel Cell Carcinoma: An Otolaryngological Point of View of An Unusual Sinonasal Mass

Merkel cell carcinoma is a pathologic diagnosis mainly observed in sun-exposed cutaneous areas, like the head and neck. Ultraviolet (UV) exposure and immunosuppression are the common predisposing factors. Merkel cell carcinoma of the head and neck is quite an uncommon disease. This case report involves a 56-year-old man who exhibited a skin lesion on the nasal dorsum with a mass in the right maxillary sinus. The biopsies from both sides were diagnostic for Merkel cell carcinoma. The patient underwent endoscopic sinus surgery and removal of the skin lesion with free margins. The patient has been free of disease for the last 20 months now and maintains follow-up with endoscopy and imaging in the Ear Nose Throat office. Only a few cases of Merkel cell carcinoma of the nasal mucosa have been reported in the literature. We report our approach and management of this rare pathologic presentation.

18F-FDG PET/CT and PET/MRI fusion imaging for neuroendocrine carcinoma of the tongue: A case report

Neuroendocrine carcinoma (NEC) involving the tongue is a rare and aggressive disease that is more common in middle-aged and elderly males. We report a case of a 56-year-old male who presented to our hospital with sore throat and was found to have a mass in the left root of the tongue. ¹⁸F-FDG PET/CT revealed intense FDG uptake in the mass of the tongue base, as well as different uptake of FDG in the mid-posterior mediastinal mass, right adrenal gland, and enlarged lymph nodes in the neck and mediastinum. Gadolinium-enhanced MRI clearly showed the extent of the tongue lesion, additionally suggesting the presence of brain metastases. ¹⁸F-FDG PET/MRI fusion images of the neck were obtained on the workstation, which may have a higher diagnostic value for tongue NEC. The patient underwent a biopsy of the mass in the left root of the tongue and was pathologically diagnosed with NEC. Whole-body ¹⁸F-FDG PET/CT and regional PET/MRI fusion images have complementary roles in the diagnosis of tongue NEC, and the former is mainly applied to determine the clinical stage of the disease and to guide treatment.

Small cell neuroendocrine carcinoma of buccal mucosa: Innocuous but invasive

Small cell neuroendocrine carcinoma (SNEC) was first described in the 19^th century which is usually seen in association with lung cancer and is very rare in the oral cavity. Here, we report one such case in a 39-year-old male patient who presented with swelling on the left middle third of the face for 6 months. This is the 12^th SNEC of oral cavity case so far reported in the English literature and the third case to be present on buccal mucosa. It presented as a nodular swelling over the buccal mucosa and was clinically diagnosed as a traumatic fibroma. The histopathological sections showed diffuse sheets of round cells with granular chromatin. Immunohistochemical findings helped us arrive at a final diagnosis. SNECs are highly proliferative tumors characterized by early and widespread metastases through the vascular channels. Hence, the diagnosis and appropriate management of these lesions is important to decrease the morbidity and mortality rate.

Neuroendocrine Differentiation of Skin Tumors: A Comprehensive Review

Neuroendocrine differentiation is characterized by endocrine and neuronal features with prominent dense secretory granules and neuropeptides. Neuroendocrine differentiation of skin tumors is of unknown clinical significance. Nonetheless, the acknowledgment of this line of differentiation is important to prevent diagnostic pitfalls and subsequent inappropriate management. This review aims at summarizing the skin neoplasms that can express neuroendocrine markers.

Merkel Cell Carcinoma of the Maxillary Sinus: An Unusual Presentation of a Common Tumor

Merkel cell carcinoma is most commonly seen in the skin of sun exposed areas, particularly the head and neck and is associated with Merkel cell polyomavirus. Merkel cell carcinoma at an extracutaneous mucosal site of the head and neck is rare. We report a case of a 74-year-old women who presented with an enlarging thyroid mass found to be neuroendocrine carcinoma consistent with Merkel cell carcinoma (positive for synaptophysin, chromogranin, CK20). Subsequent work up revealed a maxillary sinus mass with extension into the nasal cavity. Biopsy was diagnostic for Merkel cell carcinoma (positive for synaptophysin, chromogranin, CK20 and Merkel cell polyomavirus). There are only case reports and small case series of Merkel cell carcinoma arising in the mucosal sites of the head and neck most commonly in the oral cavity, rarely the sinonasal mucosa. Merkel cell carcinoma metastasizing to the thyroid has only been reported in three other case reports, all from skin primaries. In addition to our case, we review the literature of extracutaneous sinonasal Merkel cell carcinoma and metastases to the thyroid.

Primary small cell neuroendocrine carcinoma of the right posterior tongue

Small cell neuroendocrine carcinoma (SNEC) is an extremely aggressive tumor and mainly occurs in the lung. Primary extra-pulmonary SNEC is rare. To date, only 11 primary SNECs occurring in the oral cavity have been reported in the English literature. We describe a case of primary SNEC of the right posterior tongue in a 46-year-old man. The patient had stage IVA disease and received adjuvant chemotherapy, followed by radical surgery and radiotherapy. He remained tumor-free for 20 mo before death due to gastrointestinal metastasis. The relevant literature on the 11 previously reported patients was reviewed, and the clinical features, histopathological characteristics, differential diagnosis and therapeutic strategies of this rare tumor were analyzed.

Merkel Cell Carcinoma of the Buccal Mucosa and Lower Lip

Merkel cell carcinoma (MCC) is an uncommon relatively aggressive neuroendocrine dermal neoplasm first described in 1972 as a tumor of the sun exposed skin. Although most MCC affect the skin of the head and neck, rare primarily oral mucosal cases have been documented. Merkel cells are nondendritic neuroendocrine cells that are found not only in the skin but also the oral mucosa and give rise to MCC. Neuroendocrine cells may be found as aggregates in organs or as diffuse or isolated cells within organs and their epithelial lining. They contain peptide hormones and biogenic amines and occur in two forms: dendritic, which are not associated with nerve fibers and non-dendritic, which are associated with nerve fibers. Merkel cells as well as MCC express simple epithelium-type Cytokeratins (8, 18, 19, 20), neurosecretory substances; chromogranin A, synaptophysin, neuron-specific enolase (NSE), adhesion molecules, and villin (intermediate filament). Though weakly, they also express neural markers such as S-100 protein. Cytokeratin 20, and Cluster of differentiation 56, are the two key diagnostic markers for Merkel cells and MCC. Etiology includes UV radiation, the recently described Merkel cell polyomavirus, and long term systemic immunosuppression. The cutaneous and mucosal variants of MCC are considered aggressive tumors with a high risk for local recurrence and metastasis and should be considered in the differential diagnosis of head and neck mucosal lesions. We present two cases of primary Merkel cell carcinoma, one on the buccal mucosa and the other on the lower lip, and discuss the salient histologic, immunohistochemical and clinical features.

Clusterization in head and neck squamous carcinomas based on lncRNA expression: molecular and clinical correlates

BACKGROUND

Long non-coding RNAs (lncRNAs) have emerged as key players in a remarkably variety of biological processes and pathologic conditions, including cancer. Next-generation sequencing technologies and bioinformatics procedures predict the existence of tens of thousands of lncRNAs, from which we know the functions of only a handful of them, and very little is known in cancer types such as head and neck squamous cell carcinomas (HNSCCs).

RESULTS

Here, we use RNAseq expression data from The Cancer Genome Atlas (TCGA) and various statistic and software tools in order to get insight about the lncRNome in HNSCC. Based on lncRNA expression across 426 samples, we discover five distinct tumor clusters that we compare with reported clusters based on various genomic/genetic features. Results demonstrate significant associations between lncRNA-based clustering and DNA methylation, TP53 mutation, and human papillomavirus infection. Using "guilt-by-association" procedures, we infer the possible biological functions of representative lncRNAs of each cluster. Furthermore, we found that lncRNA clustering is correlated with some important clinical and pathologic features, including patient survival after treatment, tumor grade, or sub-anatomical location.

CONCLUSIONS

We present a landscape of lncRNAs in HNSCC and provide associations with important genotypic and phenotypic features that may help to understand the disease.

Postradiotherapy small cell neuroendocrine carcinoma of base of tongue: An unusual clinical and site presentation

Small cell neuroendocrine carcinoma (NEC) of the tongue is an extremely rare entity with only seven cases reported in literature till date. These are high-grade tumors with a dismal prognosis. There is much ambiguity regarding the classification, treatment protocols and prognostic factors of these tumors due to the paucity of studies. We describe an exceptionally rare and unusual case of small cell NEC of the base of tongue arising in an elderly man 6 years after receiving radiotherapy for the treatment of squamous cell carcinoma at the same site. The diagnosis was confirmed on histopathological examination and supported by immunohistochemical positivity for neuron-specific enolase, synaptophysin, chromogranin, pan-cytokeratin, and cytokeratin 7. To the best of our knowledge, this is the first case of intraoral NEC arising many years later within the irradiated field of the initial tumor.

A Rare Primary Neuroendocrine Tumor (Typical Carcinoid) of the Sublingual Gland

A typical carcinoid is extremely rare in the oral cavity. We here present a case of a typical carcinoid arising in the sublingual gland of a 62-year-old woman. The tumor was removed by primary excision with 10 mm surgical margins and submandibular dissection. Examination of the tumor showed medium-sized tumor cells that were positive for CD56 and chromogranin A, with no necrosis, and with a mitotic count less than 1/10 HPF. A pathological diagnosis of typical carcinoid was made from both morphological and immunological examinations. One year after excision surgery, there was no tumor recurrence or neck metastasis.

Primary small cell neuroendocrine carcinoma of the oral cavity: A case report and review of the literature

Small cell neuroendocrine carcinoma (SNEC) of the oral cavity is a rare and distinctive tumor with aggressive clinical behavior. Thus far, only a small number of cases have been reported and no definitive standard treatment strategy has been determined. The current study reports a case of oral SNEC arising in the lower gingiva in a 73-year-old male. Computed tomography displayed a relatively well-defined mass measuring 2.8×2×1.4 cm in size. The mass was located in the buccal side of the right mandibular posterior gingiva and exhibited no bony involvement. Histopathological examination revealed a proliferation of small cells with ovoid- to spindle-shaped nuclei, fine granular chromatin, inconspicuous nucleoli, scant cytoplasm and high mitotic activity. Immunohistochemically, the tumor cells were positive for cytokeratin AE1/AE3, chromogranin A, synaptophysin and neuron-specific enolase. Surgical resection and radical neck dissection were performed prior to the administration of adjuvant chemotherapy with a combination of cisplatin and etoposide. No evidence of local recurrence or metastasis was observed at 14 months post-surgery.

Large cell neuroendocrine carcinoma: topic review and a unique case of metastasis to the mandible

There are few reports of large cell neuroendocrine carcinoma (LCNEC) metastasis to the head and neck region, and no cases reporting LCNEC from lung metastasizing to the mandible. LCNEC is not well reported in the literature due to recent changes in the criteria for diagnosis, revised in 2004 by the world health organization, due to its propensity for rapid growth and low 5 year prognosis. We present a 61 year old female diagnosed with LCNEC of the lung in October, 2007 treated with radiation and chemotherapy. Our patient had a PET scan performed in March, 2009 revealing no sign of metastasis. In July, 2009 she was seen for suspected sialadenitis by another department and referred to our oral and maxillofacial surgery clinic. Her signs and symptoms were consistent with metastatic disease to the mandible confirmed by histologic and immunohistochemical examination which revealed an invasive poorly differentiated non-small cell carcinoma. Palliative care was offered. Our patient died 2 years after initial diagnosis of lung cancer and 3 months after initial finding of metastatic disease. The rapid growth and spread of this cancer was surprising and knowledge of this cancer should be included in a differential diagnosis of expanding mandibular jaw lesions.

Primary neuroendocrine carcinoma in oral cavity: two case reports and review of the literature

Neuroendocrine carcinoma (NEC) is a tumor that occurs in different locations, particularly the lungs and larynx. The oral cavity is a rare site for a primary NEC. This report describes 2 cases of primary NEC in the oral cavity. Case 1 occurred in the anterior mandibular gingiva in a 25-year-old woman and presented with a special histologic appearance. This patient showed no evidence of recurrence 13 months after marginal resection of the anterior mandible. Case 2 was a primary NEC with some foci of squamous cell differentiation arising in the right buccal region in a 38-year-old woman. This patient showed no evidence of disease 8 months after tumor resection and postoperative iodine-125 brachytherapy. To the best of the authors' knowledge, case 1 is the youngest patient with NEC reported in the oral cavity to date in the English-language literature, and case 2 is the first report of a primary NEC in the buccal region.

Small cell neuroendocrine carcinoma of the oropharynx harbouring oncogenic HPV-infection

Small cell carcinoma/neuroendocrine carcinoma (SCNEC) of the oropharynx is uncommon. Recently, an association has been reported between oropharyngeal SCNEC and high-risk human papillomavirus (HPV) infection. While HPV infection confers a better prognosis for oropharyngeal squamous cell carcinoma, HPV infection does not appear to influence the biological behaviour of SCNECs, which are generally associated with poor clinical outcomes. We document two cases of SCNEC arising in the oropharynx with evidence of high-risk HPV infection. The cases highlight the expanding range of malignant oropharyngeal neoplasms that harbour oncogenic HPV infection and support the concept that, irrespective of HPV infection, neuroendocrine differentiation portends a poor prognosis.

Small cell neuroendocrine tumour of the anterior tongue: A case report

INTRODUCTION

Neuroendocrine carcinomas (NECs) are rare in the oral cavity. There is ambiguity regarding the classification of these tumours, but their aggressive nature is recognised throughout the literature. Merkel cell carcinoma (MCC) is rare and more frequent in skin, though it has also been described intra-orally. High grade neuroendocrine tumours (HGNEC) and MCCs behave aggressively and aggressive treatment strategies have been advocated. We describe the first small cell HGNEC on the anterior tongue.

PRESENTATION OF CASE

We present the first report of a pT1pN1M0 small cell HGNEC in a 75 year old man on the left lateral anterior tongue. This was widely resected with 20mm peripheral and deep margins to achieve disease clearance. Selective neck dissection of levels 1-4 was also carried out.

DISCUSSION

Histological analysis of the tumour confirmed a primary poorly differentiated neuroendocrine tumour of small cell type (small cell HGNEC). Resected node bearing tissue from levels 1-4 confirmed metastasis to a level III node with no extra capsular spread giving a pT1pN1M0 classification. Margins of 11.7mm from the invasive tumour to mucosal margin medially and 7.0mm for the deep margin despite surgical 20mm margin resection. To the best of our knowledge small cell neuroendocrine carcinoma has not been described in the anterior tongue.

CONCLUSION

The aggressive nature of this tumour type mandates aggressive surgical resection with margins similar to those now recommended for skin Merkel cell carcinomas. We advocate a wide excision margin of 20mm to give adequate clearance, with neck dissection in order to pathologically stage this cancer type.

Distribution of Y-receptors in murine lingual epithelia

Peptide hormones and their cognate receptors belonging to neuropeptide Y (NPY) family mediate diverse biological functions in a number of tissues. Recently, we discovered the presence of the gut satiation peptide YY (PYY) in saliva of mice and humans and defined its role in the regulation of food intake and body weight maintenance. Here we report the systematic analysis of expression patterns of all NPY receptors (Rs), Y1R, Y2R, Y4R, and Y5R in lingual epithelia in mice. Using four independent assays, immunohistochemistry, in situ hybridization, immunocytochemistry and RT PCR, we show that the morphologically different layers of the keratinized stratified epithelium of the dorsal layer of the tongue express Y receptors in a very distinctive yet overlapping pattern. In particular, the monolayer of basal progenitor cells expresses both Y1 and Y2 receptors. Y1Rs are present in the parabasal prickle cell layer and the granular layer, while differentiated keratinocytes display abundant Y5Rs. Y4Rs are expressed substantially in the neuronal fibers innervating the lamina propria and mechanoreceptors. Basal epithelial cells positive for Y2Rs respond robustly to PYY(3-36) by increasing intracellular Ca(2+) suggesting their possible functional interaction with salivary PYY. In taste buds of the circumvallate papillae, some taste receptor cells (TRCs) express YRs localized primarily at the apical domain, indicative of their potential role in taste perception. Some of the YR-positive TRCs are co-localized with neuronal cell adhesion molecule (NCAM), suggesting that these TRCs may have synaptic contacts with nerve terminals. In summary, we show that all YRs are abundantly expressed in multiple lingual cell types, including epithelial progenitors, keratinocytes, neuronal dendrites and TRCs. These results suggest that these receptors may be involved in the mediation of a wide variety of functions, including proliferation, differentiation, motility, taste perception and satiation.

Extracutaneous Merkel cell carcinomas harbor polyomavirus DNA

Merkel cell carcinoma is a neuroendocrine tumor, with characteristic morphological and immunohistochemical features. Originally reported as primary carcinoma of skin, it has been described in numerous other sites such as lymph nodes, oral cavity, breast, vaginal walls, and salivary glands. Recent studies have revealed in cutaneous Merkel cell carcinomas a clonally integrated polyomavirus, named Merkel cell polyomavirus. The aim of the present study was to verify the presence of Merkel cell polyomavirus in 5 cases of primary Merkel cell carcinomas of lymph nodes and 1 case of parotid gland to investigate similarities or differences among Merkel cell carcinomas from various sites. Cases studied were 5 primary Merkel cell carcinomas in lymph nodes, 1 in the parotid gland, and 12 in the skin. Twelve cases of primary and metastatic small cell carcinoma of the lung were also investigated. Immunohistochemistry for keratin 20, chromogranin, synaptophysin, and thyroid transcription factor 1 was performed in all cases. Viral DNA was studied using polymerase chain reaction assay and the products evaluated in agarose gel and sequenced. Cytokeratin 20 and Merkel cell polyomavirus were detected in all cases of primary Merkel cell carcinoma irrespective of their site of origin. On the contrary, all cases of pulmonary small cell carcinoma were negative for both Merkel cell polyomavirus and cytokeratin 20. It appears that cutaneous and extracutaneous Merkel cell carcinomas share similar histologic, immunohistochemical, and molecular features. This is further evidence that Merkel cell carcinomas are a multiorgan carcinoma and that Merkel cell polyomavirus might play a role in the pathogenesis of this neoplasm.

Primary typical carcinoid tumour in the retromolar region with prominent squamous differentiation: a case report

Primary carcinoid tumours of the oral cavity are rare, with only one case of atypical carcinoid tumour reported in the literature. In this article, a case of primary typical carcinoid tumour in the retromolar region in a 46-year-old woman is described. Histologically, the tumour was characterized by submucosal proliferation of medium-sized monomorphous epithelioid cells with an organoid and nesting pattern of growth. Mitoses and necrosis were not found. Prominent squamous differentiation was present. Immunohistochemically, the tumour was diffuse positive for cytokeratin (CK) (AE1/AE3), CK7, p63, neurone-specific enolase, synaptophysin, and chromogranin. To the authors' knowledge, this is the first report of primary typical carcinoid tumour in the oral cavity.