Highly accurate diagnosis of cancer in thyroid nodules with follicular neoplasm/suspicious for a follicular neoplasm cytology by ThyroSeq v2 next-generation sequencing assay.

BACKGROUND: Fine-needle aspiration (FNA) cytology is a common approach to evaluating thyroid nodules, although 20% to 30% of FNAs have indeterminate cytology, which hampers the appropriate management of these patients. Follicular (or oncocytic) neoplasm/suspicious for a follicular (or oncocytic) neoplasm (FN/SFN) is a common indeterminate diagnosis with a cancer risk of approximately 15% to 30%. In this study, the authors tested whether the most complete next-generation sequencing (NGS) panel of genetic markers could significantly improve cancer diagnosis in these nodules. METHODS: The evaluation of 143 consecutive FNA samples with a cytologic diagnosis of FN/SFN from patients with known surgical outcomes included 91 retrospective samples and 52 prospective samples. Analyses were performed on a proprietary sequencer using the targeted ThyroSeq v2 NGS panel, which simultaneously tests for point mutations in 13 genes and for 42 types of gene fusions that occur in thyroid cancer. The expression of 8 genes was used to assess the cellular composition of FNA samples. RESULTS: In the entire cohort, histologic analysis revealed 104 benign nodules and 39 malignant nodules. The most common point mutations involved the neuroblastoma RAS viral oncogene homolog (NRAS), followed by the Kirsten rat sarcoma viral oncogene homolog (KRAS), the telomerase reverse transcriptase (TERT) gene, and the thyroid-stimulating hormone receptor (TSHR) gene. The identified fusions involved the thyroid adenoma associated (THADA) gene; the peroxisome proliferator-activated receptor γ (PPARG) gene; and the neurotrophic tyrosine kinase, receptor, type 3 (NTRK3) gene. Performance characteristics were similar in the retrospective and prospective groups. Among all FN/SFN nodules, preoperative ThyroSeq v2 performed with 90% sensitivity (95% confidence interval [CI], 80%-99%), 93% specificity (95% CI, 88%-98%), a positive predictive value of 83% (95% CI, 72%-95%), a negative predictive value of 96% (95% CI, 92%-100%), and 92% accuracy (95% CI, 88%-97%). CONCLUSIONS: The current results indicate that comprehensive genotyping of thyroid nodules using a broad NGS panel provides a highly accurate diagnosis for nodules with FN/SFN cytology and should facilitate the optimal management of these patients.

KRAS mutational analysis and immunohistochemical studies can help distinguish pancreatic metastases from primary lung adenocarcinomas.

Lung metastases from primary pancreatic adenocarcinomas often have mucinous features, which makes them difficult to distinguish from the primary lung adenocarcinoma. We explored the potential utility of KRAS mutational status and immunohistochemical studies in the evaluation of adenocarcinomas in the lungs of patients with known pancreatic cancer. Metastatic pancreatic cancer cases had fewer solitary lung lesions (5 (15%) versus 37 (95%) for lung primaries; P=0.0001), more tumors with pure (100%) mucinous morphology (16 (50%) versus 9 (23%) for lung primaries; P=0.0037), and more frequent KRAS mutations (24 (75%) versus 18 (46%) for lung primaries; P=0.0093). Presence of the KRAS G12C mutation had 96% specificity and positive predictive value for lung adenocarcinoma, whereas G12R was 99% specific for pancreatic cancer with a positive predictive value of 86%. Of the 18 KRAS mutated mucinous lung tumors, only 3 (16%) occurred in nonsmokers. Conversely, of the 19 KRAS mutated pancreatic cancer metastases, 11 (58%) occurred in nonsmokers. The median overall survival was significantly shorter for patients with metastatic tumors when compared with patients with primary mucinous tumors (19 months, 95% confidence interval, 10-28 months versus 55 months, 95% confidence interval, 39-70 months, P=0.005). CK20 and CDX2 positivity supported metastatic pancreatic cancer, whereas TTF-1 positivity supported primary lung adenocarcinoma. In summary, KRAS G12C mutations, TTF-1, and napsin A were associated with primary lung adenocarcinoma, whereas KRAS G12R mutations, CK20, and CDX2 favored pancreatic adenocarcinoma. We showed survival differences for patients whose pancreatic metastases were synchronous versus metachronous to their primary tumors, and for patients with mucinous pancreatic cancer metastases versus primary mucinous lung adenocarcinomas. Differences in KRAS mutations reflect differences in exposure to tobacco smoking and highlight biological differences between two KRAS oncogene-driven cancers.

Melanoma in infants, caused by a gene fusion involving the anaplastic lymphoma kinase (ALK).

We describe the first cases of pediatric melanoma with ALK fusion gene arising within giant congenital melanocytic nevi. Two newborn boys presented with large pigmented nodular plaques and numerous smaller satellite nevi. Additional expansile nodules developed within both nevi and invasive melanomas were diagnosed before 10 months of age in both boys. Oncogenic driver mutations in NRAS and BRAF were absent in both cases. Instead, oncogenic ZEB2::ALK fusion genes were identified in both the nevus and melanoma developing within the nevus. In both cases, tumors were noted by ultrasound in utero, demonstrated significant nodularity at birth, and progressed to melanoma in the first year of life suggesting that congenital nevi with ALK fusion genes may behave more aggressively than those with other mutations. As ALK kinase inhibitors are effective against a range of tumors with similar ALK fusion kinases, identifying ALK fusion genes in congenital melanocytic nevi may provide an opportunity for targeted therapy.

Immunohistochemistry and HPV in situ hybridization in pathologic distinction between endocervical and endometrial adenocarcinoma: a comparative tissue microarray study of 76 tumors.

OBJECTIVES: It is clinically important to determine whether adenocarcinoma present in a biopsy or curettage is of endometrial or endocervical origin. When tumors are difficult to distinguish based on routine histologic sections, immunohistochemistry and human papillomavirus (HPV) in situ hybridization may be used. MATERIALS AND METHODS: We compare immunohistochemical profile and HPV expression in 76 tumors, including various types of endocervical adenocarcinoma and the most common endometrioid type of endometrial adenocarcinoma using tumor tissue microarray. Immunostaining for p16, mammaglobin, vimentin, monoclonal carcinoembryonic antigen, estrogen receptor, progesterone receptor, and PAX-8 as well as HPV in situ hybridization was performed in 37 endocervical adenocarcinomas and 39 endometrioid-type endometrial adenocarcinomas. The staining patterns were analyzed with Bayesian network model. RESULTS: The markers with the highest discriminatory values were p16, HPV, vimentin, estrogen receptor, and monoclonal carcinoembryonic antigen. The various histologic types of endocervical adenocarcinoma showed similar immunohistochemical profile, and most were positive for p16 (86%) and HPV (65%). Most (90%) of the endometrial adenocarcinomas were positive for vimentin and estrogen receptor, all were negative for HPV, and 97% were negative for carcinoembryonic antigen. CONCLUSIONS: Immunohistochemical testing with multiple markers and HPV testing aids in diagnostic evaluation of adenocarcinomas of endocervix and endometrium and is recommended in tumors of uncertain origin.

NKX3.1 Expression and Molecular Characterization of Secretory Myoepithelial Carcinoma (SMCA): Advancing the Case for a Salivary Mucous Acinar Phenotype.

BACKGROUND: Secretory myoepithelial carcinomas (SMCA) are rare, mucinous, signet ring predominant tumors with primitive myoepithelial features. While many mucinous salivary gland tumors have now been molecularly characterized, key drivers in SMCA have yet to be elucidated. Recently, NKX3.1, a homeodomain transcription factor implicated in salivary mucous acinar development was also shown in a subset of salivary mucinous neoplasms, salivary intraductal papillary mucinous neoplasms (SG-IPMN). To date, NKX3.1 expression has not been characterized in other mucinous salivary lesions. Here, we report molecular and extended immunophenotypic findings in SMCA and NKX3.1 expression in the context of other head and neck lesions. METHODS: We retrieved 4 previously reported SMCA, performed additional immunohistochemical and targeted next-generation sequencing (NGS). We also investigated the use of NKX3.1 as a marker for SMCA in the context of its prevalence and extent (using H-score) in a mixed cohort of retrospectively and prospectively tested head and neck lesions (n = 223) and non-neoplastic tissues (n = 66). RESULTS: NKX3.1 positivity was confirmed in normal mucous acini as well as in mucous acinar class of lesions (5/6, mean H-score: 136.7), including mucinous adenocarcinomas (3/4), SG-IPMN (1/1), and microsecretory adenocarcinoma (MSA) (1/1). All SMCA were positive. Fluorescence in situ hybridization for SS18 rearrangements were negative in all successfully tested cases (0/3). NGS was successful in two cases (cases 3 and 4). Case 3 demonstrated a PTEN c.655C>T p.Q219* mutation and a SEC16A::NOTCH1 fusion while case 4 (clinically aggressive) showed a PTEN c.1026+1G>A p.K342 splice site variant, aTP53 c.524G>A p.R175H mutation and a higher tumor mutation burden (29 per Mb). PTEN immunohistochemical loss was confirmed in both cases and a subset of tumor cells showed strong (extreme) staining for P53 in Case 4. CONCLUSION: Despite a partial myoepithelial phenotype, SMCA, along with mucinous adenocarcinomas/SG-IPMN and MSA, provisionally constitute a mucous acinar class of tumors based on morphology and NKX3.1 expression. Like salivary mucinous adenocarcinomas/SG-IPMN, SMCA also show alterations of the PTEN/PI3K/AKT pathway and may show progressive molecular alterations. We document the first extramammary tumor with a SEC16A::NOTCH1 fusion.

Neoadjuvant nivolumab for patients with resectable HPV-positive and HPV-negative squamous cell carcinomas of the head and neck in the CheckMate 358 trial.

BACKGROUND: Head and neck squamous cell carcinomas (HNSCCs) are common malignancies caused by carcinogens, including tobacco and alcohol, or infection with human papillomavirus (HPV). Immune checkpoint inhibitors targeting the programmed cell death 1 (PD-1) pathway are effective against unresectable recurrent/metastatic HNSCC. Here, we explored the safety and efficacy of anti-PD-1 therapy in at-risk resectable HPV-positive and HPV-negative HNSCC in the neoadjuvant setting. METHODS: The phase I/II CheckMate 358 trial in virus-associated cancers assessed neoadjuvant nivolumab in patients with previously untreated, resectable HPV-positive or HPV-negative HNSCC. Patients received nivolumab 240 mg intravenously on days 1 and 15, with surgery planned by day 29. Safety/tolerability (primary endpoint) was assessed by monitoring adverse events (AEs) and surgical delays. Radiographic response was measured before surgery using RECIST v1.1, adapted for a single post-nivolumab evaluation. Pathologic specimens were examined for treatment response using immune-based criteria. RESULTS: From November 2015 to December 2017, 52 patients with AJCC (seventh edition) stage III-IV resectable HNSCC received neoadjuvant nivolumab (26 HPV-positive, 26 HPV-negative). Any-grade treatment-related AEs (TRAEs) occurred in 19 patients (73.1%) and 14 patients (53.8%) in the HPV-positive and HPV-negative cohorts, respectively; grade 3-4 TRAEs occurred in five (19.2%) and three patients (11.5%), respectively. No patient had a protocol-defined TRAE-related surgical delay (>4 weeks). Thirty-eight patients were reported as undergoing complete surgical resection, 10 had a planned post-nivolumab biopsy instead of definitive surgery due to a protocol misinterpretation, and four did not undergo surgery or biopsy, including two with tumor progression. Radiographic response rates in 49 evaluable patients were 12.0% and 8.3% in the HPV-positive and HPV-negative cohorts, respectively. There were no complete pathologic responses by site or central review in operated patients. Among 17 centrally evaluable HPV-positive tumors, one (5.9%) achieved major pathological response and three (17.6%) achieved partial pathologic response (pPR); among 17 centrally evaluable HPV-negative tumors, one (5.9%) achieved pPR. CONCLUSIONS: Neoadjuvant nivolumab was generally safe and induced pathologic regressions in HPV-positive (23.5%) and HPV-negative (5.9%) tumors. Combinatorial neoadjuvant treatment regimens, and continued postoperative therapy for high-risk tumors, are warranted in future trials to enhance the efficacy of this approach. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov NCT02488759; https://clinicaltrials.gov/ct2/show/NCT02488759.

Histologic Classification and Molecular Signature of Polymorphous Adenocarcinoma (PAC) and Cribriform Adenocarcinoma of Salivary Gland (CASG): An International Interobserver Study.

Polymorphous adenocarcinoma (PAC) shows histologic diversity with streaming and targetoid features whereas cribriform adenocarcinoma of salivary gland (CASG) demonstrates predominantly cribriform and solid patterns with glomeruloid structures and optically clear nuclei. Opinions diverge on whether CASG represents a separate entity or a variant of PAC. We aimed to assess the level of agreement among 25 expert Head and Neck pathologists in classifying these tumors. Digital slides of 48 cases were reviewed and classified as: PAC, CASG, tumors with ≥50% of papillary architecture (PAP), and tumors with indeterminate features (IND). The consensus diagnoses were correlated with a previously reported molecular alteration. The consensus diagnoses were PAC in 18/48, CASG in16/48, PAP in 3/48, and IND in 11/48. There was a fair interobserver agreement in classifying the tumors (κ=0.370). The full consensus was achieved in 3 (6%) cases, all of which were classified as PAC. A moderate agreement was reached for PAC (κ=0.504) and PAP (κ=0.561), and a fair agreement was reached for CASG (κ=0.390). IND had only slight diagnostic concordance (κ=0.091). PAC predominantly harbored PRKD1 hotspot mutation, whereas CASG was associated with fusion involving PRKD1, PRKD2, or PRKD3. However, such molecular events were not exclusive as 7% of PAC had fusion and 13% of CASG had mutation. In conclusion, a fair to moderate interobserver agreement can be achieved in classifying PAC and CASG. However, a subset (23%) showed indeterminate features and was difficult to place along the morphologic spectrum of PAC/CASG among expert pathologists. This may explain the controversy in classifying these tumors.

MicroRNA expression profiles in thyroid tumors.

MicroRNAs (miRNAs) constitute a recently identified class of small endogenous noncoding RNAs that act as negative regulators of the protein-coding gene expression and may impact cell differentiation, proliferation and survival, i.e., all fundamental cellular processes implicated in carcinogenesis. miRNA expression is deregulated in many types of human cancers, including thyroid cancer. The purpose of this review is to summarize the existing findings of miRNA deregulation in thyroid tumors and its potential role in thyroid cancer biology and molecular diagnostics.

Colorectal poorly differentiated neuroendocrine carcinomas frequently exhibit BRAF mutations and are associated with poor overall survival.

The molecular alterations in colorectal poorly differentiated neuroendocrine carcinoma remain incompletely characterized, particularly with respect to mutations in BRAF and KRAS. We analyzed 32 colorectal poorly differentiated neuroendocrine carcinomas and 40 colorectal poorly differentiated conventional adenocarcinomas for mutations in KRAS and BRAF and for DNA mismatch repair protein abnormalities to correlate histopathology with molecular alterations and survival. Compared with poorly differentiated conventional adenocarcinoma, poorly differentiated neuroendocrine carcinoma frequently harbored BRAF mutations (59% versus 5%; P < .001) and less frequently demonstrated KRAS codon 12 or 13 mutations (17% versus 43%; P = .03). BRAF mutations were identified in both pure poorly differentiated neuroendocrine carcinoma (60%) and poorly differentiated neuroendocrine carcinoma associated with a signet ring cell adenocarcinoma component (82%). Most (93%) poorly differentiated neuroendocrine carcinomas demonstrated proficient DNA mismatch repair by either microsatellite instability polymerase chain reaction or DNA mismatch repair immunohistochemistry. Patients with poorly differentiated neuroendocrine carcinoma had a significantly worse overall survival compared with patients with poorly differentiated conventional adenocarcinoma (P < .001). There was no significant difference in overall survival between patients with pure poorly differentiated neuroendocrine carcinoma and patients with both poorly differentiated neuroendocrine carcinoma and adenocarcinoma components (P = .5). In conclusion, colorectal poorly differentiated neuroendocrine carcinomas frequently harbor BRAF mutations and are associated with poor overall survival.

Impact of the Multi-Gene ThyroSeq Next-Generation Sequencing Assay on Cancer Diagnosis in Thyroid Nodules with Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance Cytology.

BACKGROUND: Fine-needle aspiration (FNA) cytology is a common approach to evaluate thyroid nodules. It offers definitive diagnosis of a benign or malignant nodule in the majority of cases. However, 10-25% of nodules yield one of three indeterminate cytologic diagnoses, leading to suboptimal management of these patients. Atypia of undetermined significance/follicular lesion of undermined significance (AUS/FLUS) is a common indeterminate diagnosis, with the cancer risk ranging from 6% to 48%. This study assessed whether a multi-gene next-generation sequencing (NGS) assay can offer significant improvement in diagnosis in AUS/FLUS nodules. METHODS: From May 2014 to March 2015, 465 consecutive FNA samples with the cytologic diagnosis of AUS/FLUS underwent prospective molecular testing using the ThyroSeq v2.1 panel. The panel included 14 genes analyzed for point mutations and 42 types of gene fusions occurring in thyroid cancer. In addition, eight genes were assessed for expression in order to evaluate the cell composition of FNA samples. Ninety-eight (21%) of these nodules had definitive surgical (n = 96) or nonsurgical (n = 2) follow-up and were used to determine the assay performance. RESULTS: Among 465 AUS/FLUS nodules, three were found to be composed of parathyroid cells and 462 of thyroid follicular cells. Of the latter, 31 (6.7%) were positive for mutations. The most frequently mutated genes were NRAS and HRAS, and overall point mutations in seven different genes and five types of gene fusions were identified in these nodules. Among 98 nodules with known outcome, histologic analysis revealed 22 (22.5%) cancers. ThyroSeq v2.1 was able to classify 20/22 cancers correctly, showing a sensitivity of 90.9% [confidence interval (CI) 78.8-100], specificity of 92.1% [CI 86.0-98.2], positive predictive value of 76.9% [CI 60.7-93.1], and negative predictive value of 97.2% [CI 78.8-100], with an overall accuracy of 91.8% [CI 86.4-97.3]. CONCLUSIONS: The results of the study demonstrate that the ThyroSeq v2.1 multi-gene NGS panel of molecular markers provides both high sensitivity and high specificity for cancer detection in thyroid nodules with AUS/FLUS cytology, which should allow improved management for these patients.

BRAF-mutated microsatellite stable colorectal carcinoma: an aggressive adenocarcinoma with reduced CDX2 and increased cytokeratin 7 immunohistochemical expression.

Reduced CDX2 and cytokeratin 20 (CK20) expression in colorectal carcinoma with BRAF mutation and high-level microsatellite instability (MSI-H) has been well documented. The immunophenotype of BRAF-mutated microsatellite stable (MSS) colorectal carcinoma has not been reported. We analyzed 205 colorectal carcinomas including 28 BRAF-mutated MSS, 53 BRAF-mutated MSI-H, and 124 BRAF wild-type MSS tumors for CDX2, cytokeratin 7 (CK7), and CK20 immunohistochemical expression. CDX2 was scored semiquantitatively for both staining intensity and percent of tumor cells staining and a modified CDX2 H-score was calculated. Patients with BRAF-mutated MSS colorectal carcinomas were more frequently stage IV at presentation compared to patients with BRAF-mutated MSI-H colorectal carcinomas and BRAF wild-type MSS colorectal carcinomas (32% versus 8% versus 15%, P < .001). BRAF-mutated MSS colorectal carcinoma displayed reduced CDX2 expression compared to BRAF wild-type MSS colorectal carcinoma (75% versus 94%; mean CDX2 H-score 98 versus 150, P < .001). CK7 expression was more often identified in BRAF-mutated MSS colorectal carcinoma compared to both BRAF-mutated MSI-H colorectal carcinoma and BRAF wild-type MSS colorectal carcinoma (39% versus 6% versus 6%, P = .0001). BRAF-mutated MSI-H colorectal carcinomas were less often CK20 positive compared to BRAF-mutated MSS and BRAF wild-type MSS tumors (70% versus 93% versus 90%, P = 0.001). In summary, BRAF-mutated MSS colorectal carcinoma often displays reduced CDX2 and increased CK7 expression. Knowledge of this altered immunophenotype is important as patients with BRAF-mutated MSS colorectal carcinoma often present with metastatic disease and the altered tumor immunophenotype may lead to the erroneous assumption that origin from the colon/rectum is unlikely.

Occult Primary Head and Neck Squamous Cell Carcinoma: Utility of Discovering Primary Lesions.

OBJECTIVE: Cancer of an unknown primary (CUP) squamous cell carcinoma metastatic to cervical lymph nodes is a challenging problem for the treating physician. Our aim is to determine if identification of the primary tumor is associated with improved oncologic outcomes and/or tumor characteristics including human papilloma virus (HPV) status. STUDY DESIGN: Retrospective, matched-pairs analysis contrasting 2 cohorts based upon discovery of primary lesion. SETTING: Tertiary teaching hospital. SUBJECTS AND METHODS: Records of 136 patients initially diagnosed as carcinoma of unknown primary were retrospectively reviewed (1980-2010) and divided into 2 cohorts based on discovery of the primary lesion. Primary outcome measures were overall survival and time to recurrence according to Kaplan-Meier analysis. A nested subset of 22 patients in which the primary was discovered were matched to 22 patients remaining undiscovered according to nodal stage and age. RESULTS: Discovered lesions were more likely to exhibit HPV positivity (P < .001). Matched-pairs analyses demonstrated that discovery of the primary was associated with better overall survival (HR = 0.125; 95% confidence interval [CI], 0.019-0.822; P = .030). Discovery of the primary was associated with improved cause-specific survival (HR = 0.142; 95% CI, 0.021-0.93; P = .0418) and disease-free survival (HR = 0.25; 95% CI, 0.069-0.91; P = .03). CONCLUSION: HPV positivity is associated with discovery of the primary tumor. Discovery of the primary lesion is associated with improved overall survival, cause-specific survival, and disease-free survival in patients initially presenting as CUP in matched-pair and cohort comparison analyses.

Lynch syndrome-associated colorectal carcinoma: frequent involvement of the left colon and rectum and late-onset presentation supports a universal screening approach.

The optimal strategy for screening patients with colorectal carcinoma for Lynch syndrome (LS) is a subject of continued debate in the literature with some advocating universal screening while others arguing for selective screening. We evaluated 1292 colorectal carcinomas for DNA mismatch repair protein abnormalities and identified 150 (11.6%) tumors demonstrating high-levels of microsatellite instability (MSI-H). MSI-H colorectal carcinomas were divided into sporadic (112/1292, 8.7%) and LS/probable LS-associated (38/1292, 2.9%) groups based on BRAF V600E mutation, MLH1 promoter hypermethylation, cancer history, and germline mismatch repair gene mutation. All MSI-H colorectal carcinomas were analyzed for grade, location, and tumor histology. The utility of the revised Bethesda guidelines and published predictive pathology models for MSI-H colorectal carcinomas (PREDICT and MSPath) were evaluated. Left-sided MSI-H colorectal carcinomas were more frequently associated with LS compared with right-sided MSI-H colorectal carcinomas (12/21, 57% versus 26/129, 20%, P = .0008). There was no significant difference in histology between sporadic MSI-H and LS/probable LS-associated colorectal carcinomas except for a slightly higher proportion of sporadic MSI-H tumors demonstrating tumor-infiltrating lymphocytes (81% versus 61%, P = .015). Neither pathology predictive model identified all LS-associated colorectal carcinomas (PREDICT: 33/38, 87%; MSPath: 35/38, 92%). 12/117 (10%) MSI-H colorectal carcinomas identified in patients >60 years were LS/probable LS-associated. Our results demonstrate that models of predicting MSI-H fail to identify LS-associated colorectal carcinoma given their reliance on right-sided location. A significant proportion (32%) of LS-associated colorectal carcinoma is identified in patients >60 years. Finally, our results demonstrate similar morphologic features between LS-associated and sporadic MSI-H colorectal carcinomas.

Thyroid paragangliomas are locally aggressive.

BACKGROUND: Thyroid paraganglioma (TP) is a very rare neoplasm that can be misdiagnosed. We evaluated the clinical and pathologic characteristics of three patients with TP. PATIENT FINDINGS: The records of all patients from 1981 to 2008 who had thyroidectomy with a final histologic diagnosis of TP were retrieved, and histology was reviewed by a single pathologist. Head and neck paragangliomas arising outside of the thyroid were excluded. TP accounted for 3 of all 6782 (0.04%) patients undergoing thyroidectomy during three decades. One patient has been previously reported and will not be discussed. In the remaining two patients and a surgical pathology consult case that we also describe herein, the mean age at diagnosis was 56 years (40-67) and two patients were men. Presenting features were indicative of advanced local invasion, including stridor, tracheal invasion, compression of the great vessels, and hemoptysis. The diagnosis of TP was not suspected preoperatively; in two patients, fine-needle aspiration (FNA) cytology was inadequate for diagnosis because of excessive blood. Intraoperative frozen section analysis suggested medullary thyroid cancer in two patients and oncocytic (Hurthle) cell carcinoma in one patient. Local invasion was common, requiring concurrent tracheal resection in two of three patients, and present histologically in all three patients. In all three cases, immunohistochemical analysis was negative for cytokeratin AE1/3, calcitonin, and thyroglobulin but positive for S100, highlighting sustentacular cells. After resection of a large TP with tracheal and vascular invasion, a 67-year-old woman experienced a 7-year disease-free interval. CONCLUSIONS: Primary TP is indeed rare. It does occur in men, frequently presents with compressive symptoms, and is typically locally aggressive, but does not appear to cause symptoms suggestive of catecholamine excess. Despite invasion of adjacent structures, aggressive resection can achieve a long disease-free interval.

Large cell neuroendocrine carcinoma of the larynx: definition of an entity.

Laryngeal atypical carcinoids (AC/moderately-differentiated neuroendocrine carcinoma) are associated with moderately aggressive clinical behavior; however, a subset of tumors classified as AC have much greater aggressive potential. These tumors fulfill the proposed diagnostic criteria for pulmonary large cell neuroendocrine carcinoma, albeit in the larynx. In the current WHO classification, laryngeal large cell neuroendocrine carcinomas (LCNEC) are classified as variants of AC, whereas pulmonary LCNEC are classified as poorly-differentiated neuroendocrine carcinomas. Reported outcomes for pulmonary tumors support the separate classification of LCNEC. Five and ten year survival rates for pulmonary AC are 61-73, and 35-59%, respectively, while the 5-year survival rate for pulmonary LCNEC is as low as 30%. By extension, we postulate that the biologic potential of laryngeal LCNEC is similar to that of small-cell carcinoma (poorly-differentiated neuroendocrine carcinoma), and as such, warrants reclassification. The files of Barnes Jewish Hospital/Washington University were searched for the term "neuroendocrine" and the anatomic subsite larynx. Neuroendocrine carcinoma cases were evaluated using the WHO definitions for pulmonary AC and LCNEC; small cell carcinoma was excluded. Cases were also solicited from the larger head and neck pathology community. A literature search was also performed for cases of laryngeal neuroendocrine carcinoma, and cases which could be clearly classified as LCNEC by this scheme were captured as well. Six new cases plus four reported cases were identified which fulfill the WHO criteria for pulmonary LCNEC (eight men and two women). Nine patients presented at stage IV and 88% died of disease (DOD), 75 and 100% of these at 2 and 3 years, respectively. Laryngeal LCNEC is a rare entity, distinct from AC. We recommend that laryngeal tumors fulfilling WHO criteria for pulmonary LCNEC not be classified as variants of AC, but as variants of small cell carcinoma (poorly-differentiated neuroendocrine carcinoma) as they are associated with poorer outcome.