An uncommon case of lip swelling: Granulomatous cheilitis associated with Crohn's disease

Unbeknownst to most otolaryngologists, there is quite a range of oral manifestations which commonly manifest in the context of inflammatory bowel disease. As providers who will encounter such patients in consultation it is beneficial to be aware of that association. Lip swelling (granulomatous cheilitis) is just one such presentation, which is often otherwise mistaken for angioneurotic edema and can lead to unwarranted testing and misdirected treatment. We present such a case to highlight the educational value of this patient encounter.

Risk assessment for distant metastasis in differentiated thyroid cancer using molecular profiling: A matched case-control study

Background

Risk stratification for patients with differentiated thyroid cancer (DTC) is based primarily on pathologic tumor characteristics. Accurate preoperative prognostication could allow for more informed initial surgical recommendations, particularly among patients at a higher risk for distant metastasis (DM). The objective of this study was to characterize the genetic profile of DTC with DM and to validate a molecular‐based risk stratification.

Methods

A case‐control study design was used to analyze patients who had DTC with DM (n = 62) and a propensity matched cohort of patients who had DTC without DM after at least 5 years of follow‐up using the ThyroSeq version 3 targeted next‐generation sequencing assay. The results were classified into high‐risk, intermediate‐risk, and low‐risk of aggressive disease.

Results

Most patients who had DTC with DM (66%) had a late‐hit mutation in TERT, TP53, or PIK3CA. After propensity matching by age, tumor size, and sex, the high‐risk molecular profile had strong association with DM (high‐risk vs intermediate‐risk: odds ratio, 25.1; 95% CI, 3.07‐204.4; P < .001; high‐risk vs low‐risk: odds ratio, 122.5; 95% CI, 14.5‐1038.4; P < .001). Overall, molecular risk categories were associated with DM risk, with a concordance index of 0.836 (95% CI, 0.759‐0.913), which remained consistent after internal validation. Within the range of 5% to 10% of DM observed in DTC, the expected probability of DM would be 0.2% to 0.4% for the low‐risk molecular profile, 4.7% to 9.4% for the intermediate‐risk molecular profile, and 19.3% to 33.5% for the high‐risk molecular profile.

Conclusions

In this matched case‐control study, genetic profiling using an available molecular assay provided accurate and robust risk stratification for DM in patients with DTC. The availability of preoperative prognostication may allow tailoring treatment for patients with DTC.

In this matched case‐control study, comprehensive genetic profiling provides accurate and robust risk stratification for distant metastasis in patients with differentiated thyroid cancer. The availability of preoperative prognostication may allow for molecular‐directed treatment recommendations to tailor care for these patients.

Evaluation of NR4A3 immunohistochemistry (IHC) and fluorescence in situ hybridization and comparison with DOG1 IHC for FNA diagnosis of acinic cell carcinoma

BACKGROUND

Acinic cell carcinoma (AcCC) is diagnostically challenging on fine-needle aspiration because it can mimic several other neoplasms or even normal acinar tissue. Immunopositivity for DOG1, especially circumferential membranous staining, can support the diagnosis of AcCC but is not entirely specific, and it is prone to technical and interpretive challenges on small specimens. NR4A3 (nuclear receptor subfamily 4 group A member 3) translocation and nuclear NR4A3 overexpression were recently described in the majority of AcCCs. Here, the authors evaluate the performance of NR4A3 immunohistochemistry (IHC) and NR4A3 break-apart fluorescence in situ hybridization (FISH) on cell block preparations and compare them with DOG1 IHC in distinguishing AcCC from other entities in the differential diagnosis.

METHODS

The authors identified 34 cytology cell blocks with lesional cells, including 11 specimens of AcCC (2 of which derived from 1 patient and showed high-grade transformation) as well as 2 secretory carcinomas, 7 salivary duct carcinomas, 4 mucoepidermoid carcinomas, 3 oncocytomas, 3 renal cell carcinomas, and 6 specimens containing nonneoplastic salivary gland tissue. NR4A3 IHC, DOG1 IHC, and NR4A3 FISH were attempted for all cases.

RESULTS

NR4A3 IHC had 81.8% sensitivity and 100% specificity for AcCC, whereas NR4A3 FISH had 36.4% sensitivity and 100% specificity, although 4 cases (3 mucoepidermoid carcinomas and 1 salivary gland tissue sample) could not be analyzed because of low cellularity. Notably, no normal acinar tissue specimens showed NR4A3 positivity by IHC or FISH. In addition, DOG1 IHC had 72.7% sensitivity and 92% specificity.

CONCLUSIONS

NR4A3 IHC is highly specific for the diagnosis of AcCC and is more sensitive than DOG1 IHC and NR4A3 FISH. In addition, NR4A3 IHC performance is not improved by the inclusion of DOG1 IHC. Finally, NR4A3 positivity resolves the perennial problem of distinguishing AcCC from normal acinar tissue.

Molecular-derived estimation of risk of malignancy for indeterminate thyroid cytology diagnoses

INTRODUCTION

One of the key features of the Bethesda System for Reporting Thyroid Cytopathology is the risk of malignancy (ROM), which guides management for each diagnostic category. However, calculation of the ROM can be challenging for indeterminate diagnoses because only a portion of cases will be resected for cytologic-histologic correlation (CHC) analyses. In the present study, we used the probability of cancer information from ThyroSeq, version 3, reports to calculate the molecular-derived (MD) ROM for indeterminate categories.

MATERIALS AND METHODS

Cytology cases with indeterminate BSRTC diagnoses and adequate molecular test results were retrieved from our cytopathology laboratory for a 12-month period. The probability of cancer information from the ThyroSeq, version 3, molecular reports were tabulated, and the mean ROM was calculated for each diagnostic category. The MDROM included noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) as a "malignant" outcome because it is considered a surgical disease.

RESULTS

A total of 361 cases had adequate material for molecular testing. The diagnostic distribution was as follows: atypia of undetermined significance/follicular lesion of undetermined significance, 271 cases (75.1%), follicular neoplasm/suspicious for a follicular neoplasm, 59 cases (16.3%), and Hürthle cell type/suspicious for a follicular neoplasm, Hürthle cell type, 31 cases (8.6%). The corresponding estimated MDROMs were 14.9%, 32.6%, and 34.4%. A comparison with the CHC data was performed, and the 95% confidence intervals of the MDROMs overlapped well with the 2 endpoint CHC values.

CONCLUSIONS

Calculation of the MDROMs provides a new method to approximate the ROMs of indeterminate diagnoses and has the advantage of potentially evaluating all cases, not just those resected. Furthermore, for those using the same platform, interinstitutional comparisons will be possible.

Intraoperative Margin Assessment in Head and Neck Cancer: A Case of Misuse and Abuse?

Surgical removal with negative margins is the preferred management of oral squamous cell carcinomas. This review summarizes statements by professional organizations and data supporting the specimen-driven approach to margin assessment. Practical aspects of the intraoperative margin assessment, as guided by gross examination, are presented. The most cost- and time-efficient method of intraoperative margin assessment depends on desired margin clearance and likelihood of other adverse histologic factors, such as extranodal extension, perineural invasion, which are likelier in advanced carcinomas. Intraoperative surgeon-pathologist communication can be improved by reporting to surgical team gross distances to all or selected closest margins, before choosing margins for microscopic frozen examination. Case specific mitigation strategies to minimize the negative impact of tumor-bed driven margin assessment or of suboptimal margin revision are proposed. Based on size, shape, histology, size of carcinoma at the margin, and orientation of the additional tissue, margin revision may be judged as adequate (conversion of a positive margin into a negative one), inadequate (positive margin remains positive), or indeterminate. The significance of anatomic subsite based labeling, radial margin sampling from the main resection specimen, and the relationship between the distance to closest margin and local control are highlighted. The modern definition of safe margin would account for other parameters, such as perineural invasion. An updated approach to resolution of frozen versus permanent sampling issues is outlined. Future studies are needed to design and validate risk models that would help to determine for individual patient what represents a safe margin and how to judge the quality of margin revision.

Performance of a Multigene Genomic Classifier in Thyroid Nodules With Indeterminate Cytology: A Prospective Blinded Multicenter Study

Question

Can the diagnosis of benign disease or cancer in thyroid nodules with indeterminate cytology be established by molecular testing instead of diagnostic surgery?

Findings

This prospective, blinded, multicenter cohort study of a multigene genomic classifier (ThyroSeq v3) test included 257 indeterminate cytology thyroid nodules with informative test results. It demonstrated a high sensitivity (94%) and reasonably high specificity (82%), with 61% of the nodules yielding a negative test result and only 3% residual cancer risk in these nodules.

Meanings

Up to 61% of patients with indeterminate cytology thyroid nodules may avoid diagnostic surgery by undergoing multigene genomic classifier testing.

Importance

Approximately 20% of fine-needle aspirations (FNA) of thyroid nodules have indeterminate cytology, most frequently Bethesda category III or IV. Diagnostic surgeries can be avoided for these patients if the nodules are reliably diagnosed as benign without surgery.

Objective

To determine the diagnostic accuracy of a multigene classifier (GC) test (ThyroSeq v3) for cytologically indeterminate thyroid nodules.

Design, Setting, and Participants

Prospective, blinded cohort study conducted at 10 medical centers, with 782 patients with 1013 nodules enrolled. Eligibility criteria were met in 256 patients with 286 nodules; central pathology review was performed on 274 nodules.

Interventions

A total of 286 FNA samples from thyroid nodules underwent molecular analysis using the multigene GC (ThyroSeq v3).

Main Outcomes and Measures

The primary outcome was diagnostic accuracy of the test for thyroid nodules with Bethesda III and IV cytology. The secondary outcome was prediction of cancer by specific genetic alterations in Bethesda III to V nodules.

Results

Of the 286 cytologically indeterminate nodules, 206 (72%) were benign, 69 (24%) malignant, and 11 (4%) noninvasive follicular thyroid neoplasms with papillary-like nuclei (NIFTP). A total of 257 (90%) nodules (154 Bethesda III, 93 Bethesda IV, and 10 Bethesda V) had informative GC analysis, with 61% classified as negative and 39% as positive. In Bethesda III and IV nodules combined, the test demonstrated a 94% (95% CI, 86%-98%) sensitivity and 82% (95% CI, 75%-87%) specificity. With a cancer/NIFTP prevalence of 28%, the negative predictive value (NPV) was 97% (95% CI, 93%-99%) and the positive predictive value (PPV) was 66% (95% CI, 56%-75%). The observed 3% false-negative rate was similar to that of benign cytology, and the missed cancers were all low-risk tumors. Among nodules testing positive, specific groups of genetic alterations had cancer probabilities varying from 59% to 100%.

Conclusions and Relevance

In this prospective, blinded, multicenter study, the multigene GC test demonstrated a high sensitivity/NPV and reasonably high specificity/PPV, which may obviate diagnostic surgery in up to 61% of patients with Bethesda III to IV indeterminate nodules, and up to 82% of all benign nodules with indeterminate cytology. Information on specific genetic alterations obtained from FNA may help inform individualized treatment of patients with a positive test result.

Adamantinoma-like Ewing Sarcoma of the Salivary Glands: A Newly Recognized Mimicker of Basaloid Salivary Carcinomas

Adamantinoma-like Ewing sarcoma (ALES) is a rare tumor that demonstrates the EWSR1-FLI1 translocation characteristic of Ewing sarcoma despite overt epithelial differentiation including diffuse expression of cytokeratins and p40. Most cases of ALES described to date have occurred in the head and neck where they can mimic a wide range of small round blue cell tumors. Because distinguishing ALES from basaloid salivary gland carcinomas can be particularly difficult, we analyzed a series of 10 ALESs that occurred in the salivary glands with the aim of identifying features that allow for better recognition of this entity. The salivary ALESs included 8 parotid gland and 2 submandibular gland tumors in patients ranging from 32 to 77 years (mean: 52 y). Nine were initially misclassified as various epithelial neoplasms. Although these tumors displayed the basaloid cytology, rosette formation, infiltrative growth, and nuclear monotony characteristic of ALES, peripheral palisading and overt keratinization were relatively rare in this site. Salivary ALESs not only displayed positivity for AE1/AE3, p40, and CD99, but also demonstrated a higher proportion of synaptophysin reactivity than has been reported for nonsalivary ALESs. These morphologic and immunohistochemical findings make ALES susceptible to misclassification as various other tumors including basal cell adenocarcinoma, adenoid cystic carcinoma, squamous cell carcinoma, NUT carcinoma, large cell neuroendocrine carcinoma and myoepithelial carcinoma. Nevertheless, monotonous cytology despite highly infiltrative growth and concomitant positivity for p40 and synaptophysin can provide important clues for consideration of ALES, and identification of the defining EWSR1-FLI1 translocations can confirm the diagnosis.

Genomic analysis of recurrences and high-grade forms of polymorphous adenocarcinoma

AIMS

Polymorphous adenocarcinoma (PAC) usually follows an indolent course, but some cases may show recurrences and high-grade features. The genetic events associated with recurrences and high-grade versions are yet to be defined. Our aim was to determine the genetic underpinning of recurrent PACs of the salivary gland and the repertoire of somatic genetic alterations in cases with high-grade histology.

METHODS AND RESULTS

Four PACs from three patients, including one case with matching primary and recurrent tumours, one de-novo high-grade PAC, and a PAC that transformed to a high-grade tumour following multiple recurrences, were subjected to targeted sequencing (Memorial Sloan Kettering Mutation Profiling of Actionable Cancer Targets assay) or whole-exome sequencing. Both matching primary and recurrent tumours, and the de-novo high-grade PAC, harboured clonal PRKD1 E710D hotspot mutations, whereas the PAC that underwent high-grade transformation upon recurrence, which was wild-type for PRKD1, harboured a PRKD2 rearrangement. The PACs analysed here also harboured mutations targeting cancer genes such as PIK3CA, SETD2, ARID1A, and NOTCH2. A clonal decomposition analysis of the matching primary and recurrent PACs revealed that a minor subclone from the primary tumour became dominant in the recurrent tumour following a clonal selection evolutionary pattern.

CONCLUSIONS

Our findings demonstrate that recurrent and high-grade PACs are underpinned by PRKD1 E710D hotspot mutations or PRKD2 rearrangements, and that recurrences of PACs may stem from the selection of pre-existing subclones in the primary tumour.

Data Set for the Reporting of Carcinomas of the Major Salivary Glands: Explanations and Recommendations of the Guidelines From the International Collaboration on Cancer Reporting

The International Collaboration on Cancer Reporting is a nonprofit organization whose goal is to develop evidence-based, internationally agreed-upon standardized data sets for each anatomic site, to be used throughout the world. Providing global standardization of pathology tumor classification, staging, and other reporting elements will lead to achieving the objective of improved patient management and enhanced epidemiologic research. Salivary gland carcinomas are relatively uncommon, and as such, meaningful data about the many histologic types are not easily compared. Morphologic overlap between tumor types makes accurate classification challenging, but there are often significant differences in patient outcomes. Therefore, issues related to tumor type, tumor grading, high-grade transformation, extent of invasion, number and size of nerves affected, and types of ancillary studies are discussed in the context of daily application to specimens from these organs. This review focuses on the data set developed for salivary gland carcinomas with discussion of the key core and noncore elements developed for inclusion by an international expert panel of head and neck and oral-maxillofacial pathologists and surgeons.

Update on Odontogenic Tumors: Proceedings of the North American Head and Neck Pathology Society

Odontogenic tumors are rare entities, often derived from the epithelial remnants in the gnathic bones following odontogenesis. This brief manuscript will seek to address recent developments pertaining to odontogenic tumors as well as particularly uncommon odontogenic tumors and the difficulties in their diagnosis.

GLIS Rearrangement is a Genomic Hallmark of Hyalinizing Trabecular Tumor of the Thyroid Gland

BACKGROUND

Hyalinizing trabecular tumor (HTT) is a rare thyroid neoplasm with a characteristic trabecular growth pattern and hyalinization. This lesion has been the subject of long-term controversy surrounding its genetic mechanisms, relationship to papillary thyroid carcinoma (PTC), and malignant potential. Due to the presence of nuclear features shared with PTC, HTT frequently contributes to a false-positive cytology, which hampers patient management. The goal of this study was to apply genome-wide sequencing analyses to elucidate the genetic mechanisms of HTT and its relationship to PTC.

METHODS

Whole-exome, RNA-Seq, and targeted next-generation sequencing analyses were performed to discover and characterize driver mutations in HTT. RNA-Seq results were used for pathway analysis. Tissue expression of GLIS3 and other proteins was detected by immunohistochemistry. The prevalence of GLIS fusions was studied in 17 tumors initially diagnosed as HTT, 220 PTC, and 10,165 thyroid fine-needle aspiration samples.

RESULTS

Using whole-exome and RNA-Seq analyses of the initial three HTT, no known thyroid tumor mutations were identified, while in-frame gene fusion between PAX8 exon 2 and GLIS3 exon 3 was detected in all tumors. Further analysis identified PAX8-GLIS3 in 13/14 (93%) and PAX8-GLIS1 in 1/14 (7%) of HTT confirmed after blind pathology review. The fusions were validated by Sanger sequencing and FISH. The fusions resulted in overexpression of the 3'-portion of GLIS3 and GLIS1 mRNA containing intact DNA-binding domains of these transcription factors and upregulation of extracellular matrix genes including collagen IV. Immunohistochemistry confirmed upregulation and deposition of collagen IV and pan-collagen in HTT. The analysis of 220 PTC revealed no PAX8-GLIS3 and one PAX8-GLIS1 fusion. PAX8-GLIS3 was prospectively identified in 8/10,165 (0.1%) indeterminate cytology fine-needle aspiration samples; 5/5 resected fusion-positive nodules were HTT on surgical pathology.

CONCLUSIONS

This study demonstrates that GLIS rearrangements, particularly PAX8-GLIS3, are highly prevalent in HTT but not in PTC. The fusions lead to overexpression of GLIS, upregulation of extracellular matrix genes, and deposition of collagens, which is a characteristic histopathologic feature of HTT. Due to unique genetic mechanisms and an indolent behavior, it is proposed to rename this tumor as "GLIS-rearranged hyalinizing trabecular adenoma."

An International Interobserver Variability Reporting of the Nuclear Scoring Criteria to Diagnose Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features: a Validation Study

The aim of the study was to assess interobserver variation in reporting nuclear features of encapsulated follicular variant of papillary thyroid carcinoma, newly reclassified as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), based on a proposed standardized scoring system. An education module was individually reviewed as a pre-evaluation teaching guide of the specific features of classical papillary carcinoma, the specific inclusion and exclusion features for the diagnosis of NIFTP, and a catalog of the standardized scoring system of the nuclear features of papillary carcinoma used to reach this diagnosis. Participants subsequently reviewed 30 cases of thyroid lesions previously scored by members of the Endocrine Pathology Society Working Group for the Re-evaluation of the Encapsulated Follicular Variant of Papillary Thyroid Carcinoma. There was one uninvolved reference image to demonstrate fixation, processing, and cell size and one image from each case for scoring, with results recorded for each participant. The location of training (country and program), years as a practicing pathologist, and approximate number of thyroid gland surgical cases diagnosed per year were recorded. The degree of agreement between participants was assessed by kappa statistics, using the individual criteria and the average composite scores of the Working Group as a point of comparison. Using the Nuclear Standardized Scoring System, the interobserver agreement for final diagnosis score was generally excellent: unweighted and weighted kappa values between individual observers ranging from 0.242 to 0.930 (average 0.626). There was significant agreement between observers in reaching an interpretation of the presence or absence of nuclear features to diagnose NIFTP (score 0-1 versus score of 2-3), with California pathologists, 0.63 (median 0.66, SD 0.15); Japanese pathologists, 0.64 (median 0.66, SD 0.16); and UK pathologists, 0.60 (median 0.57, SD 014) compared to the expert panel, 0.70 (median 0.73, SD 0.19). The use of the nuclear scoring system to evaluate the nuclear features of papillary thyroid carcinoma as applied to reach the diagnosis of NIFTP shows a good to substantial interobserver agreement, suggesting that consensus can be reached in diagnosing the nuclear features required for this newly reclassified neoplasm.

AHNS Series: Do you know your guidelines? AHNS Endocrine Section Consensus Statement: State-of-the-art thyroid surgical recommendations in the era of noninvasive follicular thyroid neoplasm with papillary-like nuclear features

The newly introduced pathologic diagnosis of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) will result in less bilateral thyroid surgery as well as deescalation in T4 suppressive and radioactive iodine treatment. Although, NIFTP is a nonmalignant lesion that has nuclear features of some papillary malignancies, the challenge for the surgeon is to identify a lesion as possibly NIFTP before the pathologic diagnosis. NIFTP, due to its reduction of overall rates of malignancy, will result in the initial surgical pendulum swinging toward lobectomy instead of initial total thyroidectomy. This American Head and Neck Society endocrine section consensus statement is intended to inform preoperative evaluation to attempt to identify those patients whose final pathology report may ultimately harbor NIFTP and can be offered a conservative surgical plan to assist in cost-effective, optimal management of patients with NIFTP.

Prospective validation of a molecular prognostication panel for clival chordoma

OBJECTIVE

There are currently no reliable means to predict the wide variability in behavior of clival chordoma so as to guide clinical decision-making and patient education. Furthermore, there is no method of predicting a tumor's response to radiation therapy.

METHODS

A molecular prognostication panel, consisting of fluorescence in situ hybridization (FISH) of the chromosomal loci 1p36 and 9p21, as well as immunohistochemistry for Ki-67, was prospectively evaluated in 105 clival chordoma samples from November 2007 to April 2016. The results were correlated with overall progression-free survival after surgery (PFSS), as well as progression-free survival after radiotherapy (PFSR).

RESULTS

Although Ki-67 and the percentages of tumor cells with 1q25 hyperploidy, 1p36 deletions, and homozygous 9p21 deletions were all found to be predictive of PFSS and PFSR in univariate analyses, only 1p36 deletions and homozygous 9p21 deletions were shown to be independently predictive in a multivariate analysis. Using a prognostication calculator formulated by a separate multivariate Cox model, two 1p36 deletion strata (0%-15% and > 15% deleted tumor cells) and three 9p21 homozygous deletion strata (0%-3%, 4%-24%, and ≥ 25% deleted tumor cells) accounted for a range of cumulative hazard ratios of 1 to 56.1 for PFSS and 1 to 75.6 for PFSR.

CONCLUSIONS

Homozygous 9p21 deletions and 1p36 deletions are independent prognostic factors in clival chordoma and can account for a wide spectrum of overall PFSS and PFSR. This panel can be used to guide management after resection of clival chordomas.

Human Papillomavirus Testing in Head and Neck Carcinomas: Guideline From the College of American Pathologists

Context Human papillomavirus (HPV) is a major cause of oropharyngeal squamous cell carcinomas, and HPV (and/or surrogate marker p16) status has emerged as a prognostic marker that significantly impacts clinical management. There is no current consensus on when to test oropharyngeal squamous cell carcinomas for HPV/p16 or on which tests to choose. Objective To develop evidence-based recommendations for the testing, application, interpretation, and reporting of HPV and surrogate marker tests in head and neck carcinomas. Design The College of American Pathologists convened a panel of experts in head and neck and molecular pathology, as well as surgical, medical, and radiation oncology, to develop recommendations. A systematic review of the literature was conducted to address 6 key questions. Final recommendations were derived from strength of evidence, open comment period feedback, and expert panel consensus. Results The major recommendations include (1) testing newly diagnosed oropharyngeal squamous cell carcinoma patients for high-risk HPV, either from the primary tumor or from cervical nodal metastases, using p16 immunohistochemistry with a 70% nuclear and cytoplasmic staining cutoff, and (2) not routinely testing nonsquamous oropharyngeal carcinomas or nonoropharyngeal carcinomas for HPV. Pathologists are to report tumors as HPV positive or p16 positive. Guidelines are provided for testing cytologic samples and handling of locoregional and distant recurrence specimens. Conclusions Based on the systematic review and on expert panel consensus, high-risk HPV testing is recommended for all new oropharyngeal squamous cell carcinoma patients, but not routinely recommended for other head and neck carcinomas.

Recurrent RET Gene Rearrangements in Intraductal Carcinomas of Salivary Gland

Intraductal carcinoma (IC) is the World Health Organization designation for lesions previously called low-grade cribriform cystadenocarcinoma. The relationship of IC to salivary duct carcinoma (SDC) is controversial, but currently these are considered distinct entities. It is hypothesized that IC and SDC should have different genomic signatures that may be identifiable by next-generation sequencing. A total of 23 ICs were identified: 14 pure IC and 9 invasive carcinomas with an intraductal component. Five invasive carcinomas were subjected to next-generation paired-end RNA sequencing. Data analysis was performed using FusionSeq and Mutation detection algorithms (MuTect and VarScan) for variant callers. Gene fusion candidates were validated by fluorescence in situ hybridization and reverse transcription polymerase chain reaction, and mutations by Sanger sequencing. Among the 9 invasive carcinomas, all except 1 were apocrine SDCs with an intraductal component. The remaining case showed typical intercalated duct type IC with invasive adenocarcinoma. The 14 pure ICs had typical intercalated duct features (2 showed hybrid intercalated/apocrine features). RNA sequencing predicted a NCOA4-RET fusion, confirmed by reverse transcription polymerase chain reaction, in the intercalated duct type IC invasive component. Six additional cases of pure IC showed RET rearrangement by fluorescence in situ hybridization (7/15=47%). No apocrine carcinomas showed RET rearrangement. RNA sequencing and Sanger sequencing identified PIK3CA (p.E545K/p.H1047R) and/or HRAS (p.Q61R) hotspot mutations in 6 of 8 (75%) apocrine carcinomas. In conclusion, 2 distinctive types of intraductal lesions are emerging based on molecular analysis. Classic intercalated type ICs commonly harbor fusions involving RET and rarely show widespread invasion. Apocrine intraductal lesions are typically associated with widespread invasion with no pure examples and show similar PIK3CA and HRAS mutations to SDC.

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features: a review for pathologists

The rising incidence of papillary thyroid carcinoma is linked in part to inclusion of noninvasive follicular variant of papillary thyroid carcinoma. Despite its designation as carcinoma, noninvasive follicular variant of papillary thyroid carcinoma appears to be exceptionally indolent, often over treated by current treatment practices. Additionally, criteria for diagnosis have historically been subjective and challenging. Recently, an international multidisciplinary collaborative group performed a clinicopathologic survey of such cases with extended follow-up and concluded based on the outcome data that a revision in nomenclature was warranted, proposing 'Noninvasive Follicular Thyroid Neoplasm with Papillary-like Nuclear Features (NIFTP).' This monograph is a synopsis and guide for pathologists on NIFTP and focuses on histologic features, including inclusion and exclusion criteria used to define NIFTP, as well as grossing guidelines, reporting practices, and potential diagnostic limitations.

Pathologic Reporting of Tall-Cell Variant of Papillary Thyroid Cancer: Have We Reached a Consensus?

BACKGROUND

Tall-cell variant (TCV) is widely believed to be a more aggressive subtype of papillary thyroid carcinoma (PTC). Despite the significance of TCV with respect to risk stratification and therapeutic decision making, its diagnosis is subject to inter-observer variability. This study aimed to determine the level of agreement among expert pathologists in the identification and reporting of TCV.

METHODS

Seventeen surgical resections for thyroid cancer containing the diagnostic term "tall cell" in their pathology reports and 22 cases diagnosed as classical PTC were selected. Cases were digitalized, and 14 expert pathologists reviewed the scanned slides blinded to the original interpretation. Each pathologist designated each case as TCV or not and answered multiple questions about diagnostic histopathologic features of TCV.

RESULTS

The overall strength of agreement for identifying TCV was fair (Fleiss kappa 0.34), and the proportion of observed agreement was 0.70. Of 22 cases originally diagnosed as PTC classical variant, 15 (68%) were reclassified as TCV by at least one expert pathologist. It was noted that four different definitions for TCV were used by the participants based on various combinations of cell height to width (H:W) ratio and the percentage of tumor cells showing that specific ratio. All pathologists agreed that the diagnosis of TCV does not rely solely on a specific H:W ratio.

CONCLUSIONS

Pathologic reporting of TCV varies among pathologists. This disagreement is a result of the lack of unanimous diagnostic criteria and variation in individual pathologists' interpretations. These discrepancies lead to over- and under-diagnosis of TCV, which has significant implications in patient management. It is imperative to understand this variability in diagnosis TCV as it relates to risk stratification and interpretation of clinical studies related to this histologic subtype of PTC. Further studies are needed to reach consensus on the diagnostic criteria of TCV.

Solitary Fibrous Tumors of the Head and Neck: A Multi-Institutional Clinicopathologic Study

Solitary fibrous tumors (SFTs) of the head and neck are uncommon. Lesions previously diagnosed in the head and neck as hemangiopericytomas (HPCs), giant cell angiofibromas (GCAs), and orbital fibrous histiocytomas (OFHs) are now recognized as within the expanded spectrum of SFTs. To better understand the clinicopathologic profile of head and neck SFTs, we performed a multi-institutional study of 88 examples. There was no sex predilection (F:M ratio 1.2), and the median patient age was 52 years (range: 15 to above 89 y). The sinonasal tract and orbit were the most common sites involved (30% and 25%), followed by the oral cavity and salivary glands (15% and 14%). Original diagnoses included HPC (25%), SFT (67%), and OFH (6%), with 1 SFT and 1 OFH noted as showing GCA-like morphology. On review, the predominant histologic pattern was classic SFT-like in 53% and cellular (former HPC-like) in 47%; lipomatous differentiation (8%) and GCA-like pattern (7%) were less prevalent. Subsets demonstrated nuclear atypia (23%), epithelioid morphology (15%), or coagulative necrosis (6%). Infiltrative growth (49%) and osseous invasion (82%) were prevalent among evaluable cases. Of the 48 SFTs with follow-up (median: 43 mo), 19 showed recurrence (40%). Of these, 4 patients were alive with disease and 4 dead of disease. Size and mitotic rate were negative prognosticators using a joint prognostic proportional hazards regression model. Three patients experienced metastasis, to lungs, parotid, bone, and skull base, including one case showing overtly sarcomatous "dedifferentiation." As a group, SFTs present in a wide anatomic and morphologic spectrum in the head and neck. Only rare examples metastasize or cause death from disease. However, the fairly high local recurrence rate underscores their aggressive potential and highlights the importance of prospective recognition.

Improving margin revision: Characterization of tumor bed margins in early oral tongue cancer

OBJECTIVES

To improve margin revision, this study characterizes the number, fragmentation, and orientation of tumor bed margins (TBM) in patients with pT1-2 pN0 squamous cell carcinoma (SCC) of the oral tongue.

MATERIALS AND METHODS

Pathology reports (n=346) were reviewed. TBM parameters were indexed. In Group 1 patients all margins were obtained from the glossectomy specimen and there were no TBM. In Revision Group/Group 2 (n=103), tumor bed was sampled to revise suboptimal margins identified by examination of the glossectomy specimen. In Group 3 (n=124), TBM were obtained before examination of the glossectomy specimen.

RESULTS AND CONCLUSIONS

Fewer TBMs were obtained per patient in Group 2 compared to Group 3 (57/103, 55% of patients with <3 vs. 117/124, 94%, ≥3 TBMs, respectively). The new margin surface was more frequently indicated in Group 2 compared to Group 3 (59/103, 57%, vs. 19/124, 15%, p<.001). If glossectomy specimen margins are accepted as the reference standard, then the TBM was 15% sensitive in Group 2 (95% confidence interval [CI], 7-29) and 32% sensitive in Group 3 (95% CI, 15-55). TBM fragmentation (23/103, 22% vs. 42/124, 34%) and frozen vs. permanent discrepancies (8/103, 3% vs. 3/124, 2%) were similar between Groups 2 and 3. The new margin surface was not indicated in 6 of 11 cases with discrepant frozen vs. permanent pathology findings, precluding judgment on final margin status. To facilitate the assessment of final margins, TBM should be represented by one tissue fragment with a marked new margin surface.