Immunohistochemical and ultrastructural analysis of bronchopulmonary neuroendocrine neoplasms. II. Well-differentiated neuroendocrine carcinomas

We have attempted to characterize a group of bronchopulmonary neoplasms that share certain structural features with true carcinoids but appear distinctly more pleomorphic and behave far more aggressively. In reviewing our files from 1973 to 1982, 11 such neoplasms were identified; the original diagnoses were "atypical bronchial carcinoid" (3 cases), "malignant carcinoid" (1 case), "bronchial carcinoid" (3 cases), "peripheral carcinoid" (2 cases), and "peripheral oat cell carcinoma" (2 cases). Of the 11 neoplasms, 5 were central and 6 were peripherally located. At presentation, 7 patients had lymph node metastases and 1 had a distant metastasis. No patient had a conventionally defined hormonal syndrome; however, 2 patients had a history of episodic flushing, one of which was associated with diarrhea. All cases were studied by light microscopy and light microscopic immunohistochemistry for NSE (neuron-specific enolase), serotonin, and broad-spectrum neuropeptides. Five cases were studied by electron microscopy. By light microscopy, the tumors were composed of solid clusters of polygonal to fusiform cells in an evident organoid arrangement. Foci of glandular and/or squamous differentiation were seen in 7 cases. Pleomorphism was moderate and mitoses were readily found. Focal necrosis was seen. By immunohistochemistry, 10 cases expressed NSE immunoreactivity. All cases demonstrated hormonal immunoreactivity; in 9 cases, immunoreactivity for more than one hormone was observed. The hormones most frequently expressed were serotonin, bombesin, gastrin, leu-enkephalin, and ACTH. By electron microscopy, all cases studied contained heterogeneous populations of neurosecretory granules; the latter, however, were not abundant and tended to aggregate either in the basal pole of the cells or, more frequently, interlacing "dendritelike" cytoplasmic processes. Aggregates of intermediate filaments were frequently seen. Basal lamina deposition was seen but gaps and larger areas of discontinuity were frequent. We believe that these neoplasms constitute a distinct pathologic entity for which the term "well-differentiated neuroendocrine carcinoma" has been proposed. Clinically, these tumors merit special attention since they are demonstrably more aggressive than true carcinoids but are distinctly less malignant than the intermediate or small cell variants of neuroendocrine carcinoma.     

Cytogenetic analysis of head and neck carcinomas.

Ten primary squamous cell carcinomas (SCC) of the head and neck were evaluated cytogenetically after 10-14 days of in vitro culture. Addition of 3% L-glutamine was essential for consistent epithelial growth of these carcinomas. Outgrowth of cells from tissue explants contained a mixture of chromosomally normal and abnormal cells; the abnormal cells had extensive changes including translocations, marker chromosomes, inversions, deletions, and duplications. In addition, all carcinomas contained cells with pulverization and double minute chromosomes (dmin). Chromosomes 11, 13, and 14 had "hotspots" of rearrangements.     

TP53 and head and neck neoplasms

Head and neck cancer is an important health problem around the world, accounting for approximately 500,000 new cases each year of head and neck squamous cell carcinoma (HNSCC). Carcinogenesis of head and neck results from a dysregulation of cellular proliferation, differentiation, and cell death. The major etiologic agents are tobacco and alcohol consumption and for some cases, human papilloma virus (HPV) infection. All three factors are associated with the disruption of a cellular pathway essential for the maintenance of cellular integrity, the p53 pathway. The objective of this review is to point out the specificity of p53 gene (TP53) alterations in head and neck cancer in relation with chemocarcinogenesis and to discuss whether or not the determination of p53 alterations will be of clinical relevance in the management of head and neck cancer in terms of prognosis and response to treatments.     

Schneiderian papillomas and nonsalivary glandular neoplasms of the head and neck.

Schneiderian papillomas and nonsalivary glandular neoplasms of the head and neck continue to be a source of confusion for both the clinician and pathologist. An update on these lesions is provided.     

Undifferentiated and dedifferentiated head and neck carcinomas

Undifferentiated carcinomas arising at salivary gland and head and neck mucosal sites may originate either de novo or through a process of dedifferentiation of a differentiated carcinoma. While in the latter group the diagnosis is largely dependent on the identification of the differentiated component or recognition of a specific genotype, the classification of undifferentiated carcinomas that lack a differentiated component is mainly based on the identification of specific genetic drivers, like for example the NUTM1 fusions in NUT carcinoma. A further category is represented by virus associated carcinomas (mainly HPV and EBV), that frequently displays an undifferentiated morphology. Overall, these tumors often represent a diagnostic challenge, especially in small biopsies. This review summarizes and discuss the diagnostic approach to the main head and neck carcinoma types that frequently or occasionally display an undifferentiated appearance, with a focus on salivary gland, oropharyngeal, nasopharyngeal and sinonasal subsites.     

Plexiform schwannoma: a clinicopathologic overview with emphasis on the head and neck region

Plexiform schwannoma is a rare variant of Schwann cell tumor. Occurring in either conventional or cellular type, they are characterized either grossly or histologically by a plexiform pattern of intraneural growth often with multinodularity. Ordinary as well as plexiform schwannoma typically arise in superficial soft tissues and show a predilection for the head and neck region. Infrequent examples arise in the setting of neurofibromatosis type 2 or schwannomatosis. The purpose of this study was to assess the frequency of plexiform schwannoma by location, to determine their syndromic association, and to analyze the clinicopathologic features of tumors affecting the head and neck region. It was found, in this not entirely random population, that plexiform schwannoma represented 4.3% of all schwannomas, 23% of head and neck region examples, 15% of cutaneous schwannomas, and lastly, 2% of 322 oral nerve sheath tumors made separately available for review. Furthermore, the association with neurofibromatosis type 2 and with schwannomatosis was 5% each.     

Tyrosine-rich crystalloids in neoplasms and tissues of the head and neck

Tyrosine-rich crystalloids were identified in three benign mixed tumors of the parotid gland, one terminal duct adenocarcinoma of a minor salivary gland, and the fibrous connective tissue of two laryngectomy specimens. Light and electron microscopic studies showed the crystalloids to be composed of irregular deposits of amorphous electron-dense material. In the salivary gland tumors this material was commonly associated with interstitial collagen and was found in greatest abundance near myoepithelial cells. This proximity suggests that the tyrosine-rich crystalloids result from the precipitation on stromal collagen of products secreted by neoplastic myoepithelial cells.     

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.     

Primary neuroendocrine carcinomas of the thymus.

Primary neuroendocrine carcinomas of the thymus are rare and comprise a wide spectrum of lesions ranging from well-differentiated to poorly-differentiated neoplasms. The classification of such tumors in the thymus is still controversial. By convention, the better-differentiated examples have been traditionally designated as thymic carcinoids and thought to represent the mediastinal counterpart of carcinoid tumors in other foregut locations. However, recent studies have shown that such neoplasms, when arising in the thymus, exhibit a much more aggressive behavior than those originating at other locations. We therefore consider these lesions to represent fully malignant neoplasms that fall within the spectrum of neuroendocrine carcinomas. The designation of well-, moderately-, or poorly-differentiated thymic neuroendocrine carcinoma is therefore favored for these tumors in the present review. Because such tumors may often adopt unusual morphological appearances, it is important to distinguish them from other more common conditions presenting at this location that may exhibit similar histological features. The clinicopathologic, immunohistochemical, and differential diagnostic features of these tumors in the mediastinum are discussed.     

Gemcitabine concurrent with radiation therapy for locally advanced head and neck carcinomas

Background

Management of advanced head and neck carcinoma is a challenging proposition. Presently concomitant chemo-irradiation has become the standard of care in such patients. Many chemotherapeutic drugs have shown radio-sensitising effects when used concomitantly along with radiation. The present study was carried out with the objective of assessing the feasibility and efficacy of low dose gemcitabine as radiosensitizer when used during radical radiotherapeutic management of patients with locally advanced head and neck carcinomas.

Patients and methods

From November 2000 to March 2003, Eighty histopathologically proven cases of squamous cell head and neck carcinoma were included in this trial, 40 patients were randomly assigned to receive radiotherapy alone and 40 patients to receive gemcitabine along with radiotherapy.

Results

All patients were assessable for toxicity and response. Severe mucositis (WHO level 5 reactions were observed in 67% patients in the CT/RT group vs 16% patients in the RT only group. No severe hematological toxicity was seen. The rates of complete and partial responses were 42.5% & 57.5% respectively for RT only and 62.5% &37.5%, respectively for CT/RT group. There was no significantdifference in the response rates at the end of treatment but disease free survival at three years was better in the CT/RT group (63.3% vs 20%). Nine of the 17 patients with complete response in the radiation only group developed relapse while no relapses were seen in CT/RT group.

Conclusion

In the present study the combination of gemcitabine and radiotherapy has not shown any statistical difference in locoregional control but survival advantage was seen as compared to radiotherapy alone. At the same time more mucosal and skin toxicity was encountered when Gemcitabine is given concurrently with radiation.     

Paragangliomas of the head and neck: immunohistochemical neuroendocrine and intermediate filament typing

Twenty-nine paragangliomas of the head and neck region including 20 glomus jugulare (GJ) and nine carotid body (CB) tumors were evaluated for the presence of neuroendocrine and intermediate filament antigens. Immunohistochemistry on formalin-fixed, paraffin-embedded tissue was used to identify: S-100 protein (S-100); neuron-specific enolase (NSE); chromogranin A (CHA); serotonin (SER); synaptophysin (SYN); cytokeratin (CK); neurofilament (NF); desmin (DES); vimentin (VIM); and glial fibrillary acidic protein (GFAP). S-100 protein staining of sustentacular cell nuclei and cytoplasm was found in all tumors and was present in chief cells in 4 of 20 GJ and 3 of 9 CB tumors. All tumors stained with at least three neuroendocrine markers (29 of 29 NSE, 28 of 29 SYN, 26 of 29 CHA, 25 of 29 SER). CK was detected in 2 GJ and 1 CB tumor using anticytokeratins AE 1/3 and CAM 5.2. Neurofilament protein could not be demonstrated in fixed material, and all tumors were negative for GFAP and desmin. Vimentin was inconsistently detected in chief and sustentacular cells. We conclude that, in formalin-fixed material, paragangliomas have S-100 protein staining of sustentacular cells with chief cells containing antigens associated with neuroendocrine differentiation. The presence of CK in some paragangliomas is consistent with recent tissue culture studies demonstrating immunoblot confirmation of CK in pheochromocytomas and represents a potential source of immunohistologic misinterpretation in diagnosis, unless a panel of markers is utilized.     

Breast carcinomas with neuroendocrine differentiation

Twenty-two breast carcinomas with membrane bound granules by electron microscopy were tested for the presence of neuron specific enolase (NSE), neuropeptides and serotonin by immunohistochemistry. By light microscopy the cases studied included infiltrating ductal carcinomas, intraductal carcinomas, apocrine carcinomas, infiltrating lobular carcinomas of both classical and alveolar types, mixed lobular/colloid carcinomas, carcinoid growth pattern and one unclassified carcinoma. Ten cases showed immunoreactivity for 1 or 2 neuropeptides in scattered cells whereas all cases were positively and rather diffusely stained with anti-NSE. Immunohistochemical staining at the ultrastructural level was carried out; the presence of neuropeptides could not be confirmed. Scattered granules were marked with gold particles when antiserum against casein was used. We conclude that neither argyrophilia, nor NSE immunoreactivity nor membrane bound granules seen by electron microscopy constitute at present sufficient evidence to designate a breast carcinoma as neuroendocrine. However, our study indicates that certain breast carcinomas of several types do include cells with neuroendocrine features demonstrable convincingly by light microscopic immunohistochemistry. We have no evidence that these breast carcinomas with neuroendocrine features behave differently from their counterparts lacking such features. The intriguing speculation is that neuropeptides produced by certain breast carcinomas may act as local modulators of tumor growth and differentiation.     

SWI/SNF-deficient head and neck neoplasms: An overview

With wide-spread use of next generation sequencing tools in surgical pathology, a variety of neoplasms have been increasingly recognized to be associated with specific recurrent defining genetic abnormalities. This has led to recognition of new genetically defined entities and refinements of preexisting heterogeneous neoplastic categories. Among these, neoplasms associated with inactivating mutations involving different subunits of the SWI/SNF chromatin remodeling complex have received special attention. In the head and neck area, SMARCB1 (INI1) and SMARCA4 (BRG1) are the main two SWI/SNF components responsible for several recently described highly aggressive undifferentiated malignancies with predilection for the soft tissue of the neck (SMARCB1-deficient malignant rhabdoid tumors in children and rare epithelioid sarcoma cases in adults) and the sinonasal tract (SMARCB1-deficient sinonasal carcinoma including a small subset of adenocarcinomas, SMARCA4-deficient sinonasal undifferentiated carcinoma and SMARCA4-deficient sinonasal teratocarcinosarcoma). Molecular studies confirmed paucity of additional genetic abnormalities in these diseases underlining the central role of SWI/SNF deficiency as the primary and frequently sole genetic driver of these lethal diseases. Initiation of clinical trials using drugs that target the SWI/SNF collapse encourages recognition and correct classification of these morphologically frequently overlapping malignancies and underpins the role of SWI/SNF immunohistochemistry as emerging powerful adjunct tool in surgical pathology of the head and neck.     

Human papillomavirus detection in head and neck squamous cell carcinomas

Squamous cell carcinomas of the head and neck (HNSCC) are a frequent diagnosis in anatomic pathology practice. Tobacco use and heavy alcohol consumption are known risk factors for HNSCC but in other cases human papillomavirus (HPV) is linked to carcinogenesis. HPV proteins E6 and E7 promote oncogenesis by blocking the action of p53 and pRB, respectively. An absence of p53 mutations in addition to expression of p16 are part of the distinct molecular profile identified in the subset of HNSCCs because of HPV. Various methods are available for HPV detection but polymerase chain reaction and in situ hybridization techniques are commonly used. Both methods are amenable for testing formalin-fixed paraffin-embedded tissue that is a sample type readily available to the pathologist. HPV is detectable in approximately a quarter of all HNSCCs, and is particularly prevalent in the oropharynx in which the positivity rates approach 40%. A vast majority of HPV-related HNSCCs are owing to HPV type 16 with types 18, 31, and 33 accounting for almost all of the remaining cases. HPV-related HNSCCs are associated with better prognosis for both recurrence and survival. This group of tumors has also been shown to respond well to radiation treatment. As the clinical relevance of HPV in HNSCCs continues to emerge, anatomic pathologists are likely to receive increasing requests for testing. Herein, the authors review the biological and clinical aspects of HPV-associated HNSCC and review techniques for HPV detection.     

Genome-wide analyses on loss of heterozygosity in head and neck squamous cell carcinomas

Head and neck squamous cell carcinoma (HNSCC) is a frequent malignancy with a poor survival rate. Identifying the tumor suppressor gene (TSG) loci by genomic studies is an important step to uncover the molecular mechanisms involved in HNSCC pathogenesis. We therefore performed comprehensive analyses on loss of heterozygosity (LOH) using a genome-wide panel of 191 microsatellite markers in 22 HNSCC samples. We found 53 markers with significantly high LOH (>30%) on 21 chromosomal arms; the highest values of those were observed on 3p, 9p, 13q, 15q, and 17p, corresponding to D3S2432 (67%), D9S921-D9S925 (67%) and GATA62F03 (86%), D13S1493 (60%), D15S211 (62%), and D17S1353 (88%), respectively. Fifteen hot spots of LOH were defined in 13 chromosomal arms: 2q22-23, 4p15.2, 4q24-25, 5q31, 8p23, 9p23-24, 9q31.3, 9q34.2, 10q21, 11q21-22.3, 14q11-13, 14q22.3, 17p13, 18q11, and 19q12 as loci reported previously in HNSCCs. Furthermore, we identified five novel hot spots of LOH on three chromosomal arms in HNSCC at 2q33 (D2S1384), 2q37 (D2S125), 8q12-13 (D8S1136), 8q24 (D8S1128), and 15q21 (D15S211). In conclusion, our comprehensive allelotype analyses have unveiled and confirmed a total of 20 possible TSG loci that could be involved in the development of HNSCC. These results provide useful clues for identification of putative TSGs involved in HNSCC by fine mapping of the suspected regions and subsequent analysis for functional genes.