Neuroendocrine carcinoma of the parotid gland: a report of two cases with ultrastructural and immunohistochemical studies

Primary neuroendocrine small cell carcinoma of the parotid gland: A case report and review of the literature

Small cell carcinoma (SCC) is a malignant epithelial tumor that predominantly arises in the lungs. Primary SCC of the parotid gland is rare and difficult to diagnose by analysis of frozen sections obtained during surgery. Due to the aggressive nature of SCC and the frequent occurrence of distant metastases, identification of the disease is important. The current study reports the case of a male patient who presented with a right parotid gland mass. The tumor was resected and evaluated by light microscopy and immunohistochemical analysis. Immunohistochemically, the tumor was positive for cytokeratin, epithelial membrane antigen, cluster of differentiation 117, synaptophysin and thyroid transcription factor-1, which indicated that the tumor was a SCC of the parotid gland. An extended resection of the right parotid gland mass and dissection of the facial nerve were performed. Following discharge from the hospital, the patient received radiation therapy postoperatively. The patient has remained disease free during five months of follow-up.

Neuroendocrine neoplasms of the head and neck: some suggestions for the new WHO classification of head and neck tumors

As knowledge and understanding in pathology evolve, classifications and nomenclature also change to reflect those advances. The 2005 World Health Organization Classification of Head and Neck Tumours was a significant step towards diagnostic standardization of head and neck neuroendocrine carcinomas; however, in the last 10 years there have been new data supporting the recognition of "large cell neuroendocrine carcinoma" as a distinctive high grade carcinoma in the head and neck, a lesion not included in the 2005 Classification. In addition, the terms "middle ear adenoma" and "carcinoid tumor of middle ear" are still widely used to describe a neoplasm that is neither a pure adenoma nor a carcinoid tumor but a lesion with variable mixed exocrine and endocrine differentiation. Largely using the diagnostic criteria of the WHO classification of neuroendocrine carcinomas of the lung, we propose the terms "neuroendocrine carcinoma, grade 1"; "neuroendocrine carcinoma, grade 2"; "neuroendocrine carcinoma, grade 3, large cell type"; and "neuroendocrine carcinoma, grade 3, small cell type" for the classification of neuroendocrine carcinomas of the head and neck in a future WHO classification. In addition, we also proposed the term "mixed epithelial neuroendocrine tumor" of the middle ear as an alternative for "middle ear adenoma" and "carcinoid tumor of the middle ear".

Moderately differentiated neuroendocrine carcinoma (atypical carcinoid) of the parotid gland: report of three cases with contemporary review of salivary neuroendocrine carcinomas

Primary neuroendocrine carcinomas (NECs) of the salivary glands are rare. Most reported NECs in that region are small cell carcinomas with few cases of large cell undifferentiated carcinoma and typical carcinoid tumors. Only two moderately differentiated NECs (atypical carcinoid tumors) have been previously reported. In the current series, the authors report three additional moderately differentiated NECs (atypical carcinoid tumors) of the parotid gland; two occurred in women and one in a man. All patients were initially treated with parotidectomy, with selective lymph node excision in one, and radiation therapy in another. Follow-up was available for two cases (18 and 79 months). One patient had two local recurrences, developing lymph node and liver metastases requiring further surgery and chemotherapy. Currently, she is alive with disease, on supportive care. The second patient is alive with no signs of recurrence. Patients' work-up excluded the possibility of metastatic NECs to the salivary glands in all cases. Histologically, the tumors demonstrated infiltrating nests, cords and trabeculae of round, oval to spindle shaped cells with moderate to focally abundant eosinophilic cytoplasm, small to prominent nucleoli and chromatin stippling. Scattered rosette-like structures were prominent in one tumor. The highest mitotic counts for the three tumors ranged from 5 to 8 mitotic figures/10 hpfs. Necrosis, focal but distinct, was noted in two tumors, vascular invasion in two tumors and perineural invasion in one tumor. Immunohistochemical staining was diagnostic of neuroendocrine carcinoma, showing uniform positive labeling with broad-spectrum cytokeratin (with a paranuclear punctuate pattern in one case), chromogranin and synaptophysin antibodies. CK20 was negative in two tumors and stained rare cells (<1%) in the third.

Small cell carcinoma of the salivary gland: a systematic literature review and two case reports

Salivary gland small cell carcinoma is a rare neoplasm, accounting for less than 1% of salivary gland tumours. Little is known about the epidemiologic factors and treatment of this lesion. The authors report two cases and perform a systematic literature search from 1960 to 2011 for articles on salivary gland small cell carcinoma. Once the papers were reviewed, a database was generated to analyse clinical and pathological features, treatments and outcomes, and an attempt was made to identify prognostic factors. Available data were retrieved for 44 cases which fully satisfied the inclusion criteria; the median age was 64.25 years and the male:female ratio was 2.4:1. The parotid gland was the most common site (79.6%). The overall 1-, 2- and 5-year survival rates were 75.3%, 56.4% and 36.6%, respectively. According to the present review, patient age, tumour size, distant metastasis and cytokeratin-20 positive immunostaining were all significant prognostic factors in a univariate analysis. No particular treatment approach appeared to improve survival. This work reinforces knowledge about salivary gland small cell carcinoma's epidemiologic features, and identifies new prognostic markers. The optimal management of this lesion remains controversial.

Advances in salivary gland pathology

This review summarizes the new findings on salivary gland pathology under the following categories: immunohistochemistry; molecular genetics; newly recognized tumour types; known tumour entities with new findings; and progression of salivary gland tumours. In the application of immunohistochemistry, CD117 can aid in highlighting the luminal cell component of various salivary gland tumours, whereas p63 or maspin can aid in highlighting the abluminal cell component. A high Ki67 index remains the most useful marker to predict adverse outcome in salivary gland carcinoma. Specific chromosomal translocations are recognized in pleomorphic adenoma (with translocation involving PLGA1 or HMGA2 gene) and mucoepidermoid carcinoma (with MECT1-MAML2 gene fusion). Newly recognized entities include: sclerosing polycystic adenosis (with recent molecular evidence supporting its neoplastic nature), sclerosing mucoepidermoid carcinoma with eosinophilia, keratocystoma, adenoma with additional stromal component (lymphadenoma, lipoadenoma and adenofibroma), cribriform adenocarcinoma of the tongue and signet ring adenocarcinoma of minor salivary gland. Known tumour entities with new findings include: salivary duct carcinoma (with newly recognized mucinous, micropapillary and sarcomatoid variants), intraductal carcinoma (with controversies in terminology), mucoepidermoid carcinoma (with newly proposed grading parameters and oncocytic variant), epithelial-myoepithelial carcinoma (with newly recognized morphological variants), small cell carcinoma (with most cases being related to Merkel cell carcinoma), extranodal marginal zone B-cell lymphoma (with specific chromosomal translocation) and chronic sclerosing sialadenitis (being a component of IgG4-related sclerosing disease). Progression of salivary gland tumours can take the form of malignant transformation of a benign tumour, progression from low-grade to high-grade carcinoma, dedifferentiation, or stromal invasion of an in situ carcinoma.

Small-cell undifferentiated carcinoma of the submandibular gland: an extremely rare extrapulmonary site

The occurrence of small-cell undifferentiated carcinoma (SCUC) has seldom been reported in the submandibular gland. A primary SCUC with immunoreactivity for neuron-specific enolase and chromogranin-A antibodies was reported in the submandibular gland of a 39-year-old man. The patient received primary tumor excision and adjuvant chemotherapy with 6 courses of cisplatin and etoposide. The patient remained free of symptoms for 12 months after treatment. Submandibular gland is an extremely rare site of extrapulmonary SCUC. Primary tumor excision and adjuvant chemotherapy with cisplatin and etoposide could be a viable option. The clinicopathologic features, differential diagnoses, and the nature of the disease are discussed.

Metastatic neuroendocrine tumors of the parotid gland

OBJECTIVES

To present 2 cases of neuroendocrine tumors of the parotid gland and to review the clinical presentation, histopathologic, and immunohistochemical findings and treatment of these rare tumors.

STUDY DESIGN

Case series.

METHODS

This study reviews 2 patients who both presented with firm masses in the parotid gland diagnosed as neuroendocrine carcinoma by histopathologic and immunohistochemical examination. The evaluation, diagnosis, and treatment are discussed.

RESULTS

Both patients underwent complete tumor extirpation via a total or subtotal parotidectomy. Both patients received postoperative radiation therapy and chemotherapy.

CONCLUSIONS

Neuroendocrine tumors of the parotid gland are uncommon lesions; however, they have a favorable prognosis as compared to their pulmonary counterparts with early diagnosis and aggressive treatment. Diagnosis is based on the immunohistochemical characteristics of the tumor. Appropriate treatment includes complete surgical excision with postoperative radiation therapy to the parotid bed with the addition of postoperative chemotherapy in patients suspected to have metastatic disease.

Fine-needle aspiration cytology of small-cell carcinoma of the parotid

Small-cell carcinomas arise uncommonly in extrapulmonary sites and are rare primary neoplasms in the salivary glands. We report on the aspiration cytology and immunohistochemical findings of a small-cell carcinoma of the parotid gland in an 81-yr-old man.

Primary large-cell neuroendocrine carcinoma of the parotid gland: immunohistochemical and molecular analysis of two cases

Pulmonary large-cell neuroendocrine carcinoma (LCNEC) is a newly proposed clinicopathologic entity; a few cases of LCNEC have been reported in other sites, such as the uterine cervix and the thymus. In the salivary glands, LCNEC is extremely rare and is not recognized as a specific entity in the World Health Organization classification. We retrospectively reviewed from our files 1675 cases of surgically resected primary parotid gland tumors and found 2 cases of LCNEC that fulfilled the criteria of pulmonary LCNEC. These cases occurred in 72- and 73-year-old men who had short histories of enlarging parotid gland tumors. The tumors were composed of large cells that exhibited organoid, solid, trabecular, and rosette-like growth patterns with a high mitotic rate and a conspicuous tendency for necrosis. The tumor cells were polygonal and characterized by a moderate nuclear:cytoplasmic ratio, coarse chromatin, and conspicuous nucleoli. Immunohistochemical examination revealed that the tumor cells were positive for six general neuroendocrine markers, cytokeratin, p53, bcl-2, epidermal growth factor receptor, and cyclin D1. Markedly reduced expressions of p21Waf1 and p27Kip1 were also noticed. The Ki-67 labeling index was more than 50% in both cases. One case showed loss of heterozygosity at TP53 accompanied by a p53 gene point mutation. Loss of heterozygosity at chromosome 9p21 was detected in both cases; one was accompanied by a p16 gene silent point mutation. Both patients died of the disease, with recurrence 5 months and 4 years after surgery, respectively. These findings indicate that LCNEC is a rare but distinct salivary gland tumor with highly aggressive biologic behavior. Multiple alterations of cell cycle regulators and tumor suppressor genes may play an important role in presenting the biologic characteristics of this rare parotid gland tumor.

Cytokeratin 20 immunoreactivity distinguishes Merkel cell (primary cutaneous neuroendocrine) carcinomas and salivary gland small cell carcinomas from small cell carcinomas of various sites

Cytokeratin 20 (CK20) is a low-molecular-weight cytokeratin (CK) that shows restricted expression in the gastrointestinal epithelium, urothelium, and Merkel cell. Recent studies have suggested that since Merkel cell (primary cutaneous neuroendocrine) carcinomas are consistently CK20-positive, this feature may help to distinguish it from pulmonary small cell carcinomas. However, only limited numbers of these tumors have been studied, and the pattern of CK20 expression in other small cell carcinomas has not been established. Therefore, we studied CK20 expression in small cell carcinomas from a wide variety of sites. Immunohistochemical study was performed on paraffin sections using CK20 antibody, coupled with antigen retrieval by pressure cooking in citrate buffer. The cases included 34 Merkel cell carcinomas and 89 small cell carcinomas from various sites (pulmonary, 37; gastrointestinal tract, nine; pharynx and tongue, two; sinonasal tract, three; salivary gland, five; larynx, nine; breast, two; thymus, three; uterine cervix and corpus, 12, prostate, three; urinary bladder, two; kidney, one; pancreas, one). In addition, all cases were immunostained with pan-CK (MNF-116) and low-molecular-weight CK (CAM5.2) antibodies to ascertain their epithelial nature. With the exception of one case, all Merkel cell carcinomas were CK20-positive; and 30 of the 33 cases showed a punctate pattern. Almost 100% of tumor cells were positive, except for two cases that showed staining of 10% and 30% of tumor cells, respectively. Among the other small cell carcinomas, only five cases were CK20-positive, including one of 37 pulmonary (40% cells positive in punctate pattern), one of 11 cervical (10% cells positive), and three of five salivary gland (100% cells positive). We conclude that CK20-positivity in a small cell carcinoma of uncertain origin strongly predicts a diagnosis of Merkel cell carcinoma, especially if the majority of tumor cells are positive. A negative CK20 reaction can practically rule out Merkel cell carcinoma, provided that an effective antigen retrieval technique is used and appropriate staining is obtained with other cytokeratin antibodies. The frequent CK20 positivity observed in salivary gland small cell carcinomas in this series suggests that at least some of them may be more closely related biologically to Merkel cell carcinoma than to pulmonary-type small cell carcinoma. This may explain why they are far less clinically aggressive than other small cell carcinomas.

Bone marrow metastases from small cell cancer of the head and neck

BACKGROUND

Primary small cell carcinoma of the head and neck is rare. Although the larynx is the most prevalent site of head and neck small cell carcinoma (SCC), this report will concentrate on SCC of the major salivary glands and paranasal sinuses. In all, 33 cases of paranasal sinus and 43 cases of major salivary gland SCC have been reported in the literature.

METHODS

We report two patients, one with submandibular gland SCC and the other with maxillary sinus SCC. A literature review of all known paranasal sinus and major salivary gland SCC with inclusion of data from these two new cases is undertaken. Discussion of all past and present cases concentrates on sites of metastasis, treatment, and survival.

RESULTS

Paranasal sinus SCCs predominantly arise from the nasal cavity, whereas the parotid gland is the primary site in three fourths of major salivary gland SCCs. One half of major salivary gland and three fourths of paranasal sinus SCCs have only local disease at presentation. Both patients in this report developed bone marrow metastases, a feature heretofore not observed in SCC from these primary sites. The patient with maxillary sinus SCC developed the syndrome of inappropriate antidiuretic hormone (SIADH).

CONCLUSION

The paranasal sinus and major salivary glands are rare primary sites for SCCs. Long-term survival with local therapy in patients with local disease can occur, but in patients with metastatic disease survival mirrors metastatic pulmonary SCC.

Paragangliomas of the head and neck. Immunohistochemical analysis of 16 cases in comparison with neuro-endocrine carcinomas

Sixteen cases of paragangliomas of the head and neck including 8 of the vagal body, 3 of the carotid body, 2 jugulotympanic, 2 vagal or jugulotympanic and 1 of the larynx were analysed. Clinically, 13 tumors were benign, 2 showed local aggressivity and 1 showed metastases. All tumors were tested with antisera directed against neuron-specific enolase (NSE), chromogranin A (CGA), S-100 protein, neurofilaments (NF), glial fibrillary acid protein (GFAP) and cytokeratin (CK). Immunohistochemical results were compared with those of 5 cases of neuroendocrine carcinoma (NC) (1 of the oral vestibule, 1 of the larynx, 1 Merkel-cell tumor of the skin and 2 medullary thyroid carcinomas). Immunoreactivity for NSE and/or CGA was always positive in all paragangliomas and NC. S-100 protein was positive in sustenticular cells in all cases of paragangliomas and focally in two cases of NC. NF and GFAP were focally positive in 3 and 2 paragangliomas respectively; and in 1 NC. CK was constantly negative in all cases of paraganglioma and constantly positive in all cases of NC. Antibody anti-CK is the single most useful immunomarker for differential diagnosis between paraganglioma, frequently benign neoplasms and NC commonly aggressive in the head and neck. These findings are consistent with the current concepts of the neuroendocrine system.

Undifferentiated carcinomas of salivary glands

Undifferentiated carcinomas of salivary glands are those epithelial malignancies whose light-optic histopathologic features are not sufficient to place them in other defined classes of carcinoma. They are ultrastructurally heterogeneous and can manifest neuroendocrine differentiation. With or without the latter, the carcinomas are biologically high-grade and rank with salivary duct and high-grade mucoepidermoid carcinomas in terms of morbidity and mortality.

Small cell carcinoma of the major salivary glands. An immunohistochemical study

Small cell carcinomas of the major salivary glands are rare tumors, accounting for less than 1% of malignant neoplasms at these sites. To date, approximately 41 such tumors have been described. They recently have been classified into two groups, based on the ultrastructural presence or absence of intracytoplasmic neuroendocrine (NE) granules, "small cell neuroendocrine carcinoma" and "small cell ductal carcinoma". This study concerns 11 primary small cell carcinomas that had been previously studied ultrastructurally; it was undertaken to determine whether these lesions possessed a neuroendocrine phenotype, using a battery of immunohistochemical stains. Antibodies to epithelial membrane antigen (EMA), cytokeratin (CK), Leu 7, vimentin (VIM), synaptophysin (SYN), chromogranin (CHR), and neuron-specific enolase (NSE) were employed, with the avidin-biotin-peroxidase complex technique and paraffin sections. All tumors in this study expressed at least one neuroendocrine marker. In eight tumors EMA was found; CK was present in all 11 cases, seven of which demonstrated focal paranuclear staining. Leu 7 was seen in eight tumors, VIM was expressed in two cases, SYN was found in three tumors, and CHR was detected in three neoplasms. Anti-neuron-specific enolase labeled eight tumors. From the preceding data one may conclude that all small cell salivary gland carcinomas have neuroendocrine characteristics, even though dense core granules cannot be demonstrated in some of them ultrastructurally.

Small cell carcinoma of the bladder. Report of five cases with immunohistochemistry and review of the literature with evaluation of prognosis according to stage

Five cases of small cell carcinoma (SCC) of the bladder are reported with pathologic and immunohistochemical findings and clinical follow-up. Sixteen additional cases reported in the literature are studied and staged according to depth of tumor infiltration of the bladder wall. In our series of five cases and those reviewed from the literature, survival appeared to be dependent on stage of the tumor, analogous to the more common transitional cell carcinoma (TCC). We report two of five patients with the longest recorded follow-up times in the literature who are alive with no evidence of disease at 4 and 6 years. Contrary to the belief that SCC of the bladder is an aggressive, rapidly disseminating tumor similar to SCC of the lung, our findings support the notion that this is a potentially curable neoplasm with a prognosis that appears to be dependent on stage and surgical resectability.