Columnar Cell Thyroid Carcinoma: A Heterogeneous Entity Demonstrating Overlap Between Papillary Thyroid Carcinoma and Follicular Neoplasms

BACKGROUND

Columnar cell papillary thyroid carcinoma (CC-PTC) is a morphologic subtype of papillary thyroid carcinoma with a variable prognosis. It is characterized by neoplastic thyroid follicular-derived cells with pseudostratified columnar morphology arranged in papillary or follicular structures with supranuclear or subnuclear vacuoles. The molecular profile of this subtype has only recently come under scrutiny, with mixed results. The aim of this study is to further explore the morphologic, immunohistochemical, and genetic profile of CC-PTC, as well as to correlate these features with clinical outcomes.

METHODS

CC-PTC cases were identified from 3 institutions. Immunohistochemistry (ER, CDX2) and molecular testing (DNA and RNA sequencing) were performed. Clinicopathologic parameters and patient outcomes were recorded.

RESULTS

Twelve cases (2006-2023) were identified, all in adults (age 45-91). Two presented with disease outside the thyroid gland (neck and mediastinum) and two presented with distant metastasis. Four were high-grade differentiated thyroid carcinomas (necrosis or mitoses), one of which died of disease. Four were noninvasive or minimally invasive, one of which locally recurred. Three patients had lymph node metastases. ER and CDX2 were positive in 73% and 50%, respectively. Pathogenic mutations were found in TERT promoter (n = 3), RAS (n = 2), ATM, NOTCH1, APC, and ESR1, along with cases bearing AGK::BRAF fusion (n = 1), BRAF VE1 expression (n = 1), and NF2 loss (n = 1).

CONCLUSIONS

This study represents the largest molecularly defined cohort of non-oncocytic thyroid carcinomas with columnar cell morphology. These tumors represent a genetically and behaviorally heterogeneous group of neoplasms, some of which have RAS-like or follicular neoplasm-like genetics, some of which have BRAF-p.V600E-like or classic papillary thyroid carcinoma-like genetics, and some of which remain unclear. Noninvasive or minimally invasive tumors showed an indolent course compared to those with angioinvasion, gross extrathyroidal growth, or high-grade morphology. Consideration could be given to reclassification of this neoplasm outside of the subtyping of papillary thyroid carcinoma in light of its genetic diversity, distinct morphology, and clinical behavior more closely aligned with follicular thyroid neoplasms.

Utility of BRAF V600E immunohistochemistry in the diagnosis of mandibular ameloblastomas

Ameloblastoma, odontogenic keratocyst (OKC), and dentigerous cyst (DC) can have similar radiographic and histological appearances. The purpose of this study was to determine the utility of BRAF immunohistochemistry in discerning mandibular ameloblastomas from OKCs and DCs. This retrospective cohort study included patients treated between 1998 and 2018. Inclusion criteria include incisional biopsy-proven mandibular ameloblastoma, OKC, or DC, and sufficient tissue for immunohistochemistry. The primary predictor variable was the type of lesion. The primary outcome variable was the presence/absence of BRAF V600E immunoreactivity. The cohort consisted of 43 patients (19 female, 24 male; mean age 48 ± 17 years). There were 22 ameloblastomas, 11 OKCs, and 10 DCs. Among ameloblastomas, 68.2% (15/22) stained positive for BRAF V600E; no OKC or DC was positive (P < 0.001). By subtype, the majority of the follicular (83.3%), unicystic (83.3%), desmoplastic (66.7%), and acanthomatous (100%) subtypes were positive, but only 33.3% of the plexiform subtype were positive. BRAF immunohistochemistry may be a useful adjunct in the differentiation of ameloblastoma from OKCs and DCs on incisional biopsies. It may be particularly useful for small samples with a prominent cystic component or equivocal histopathology. Mandibular lesions that are BRAF immunohistochemistry positive are unlikely to be DCs or OKCs.

Lung adenocarcinomas with isolated TP53 mutation: A comprehensive clinical, cytopathologic and molecular characterization

BACKGROUND

TP53 mutation is present in about 50.8% of lung adenocarcinomas, frequently in combination with other genetic alterations. However, a rare subset harbors the TP53 mutation alone.

METHODS

Next-generation sequencing was performed in 840 lung adenocarcinomas diagnosed by fine needle aspiration. Fourteen cases (1.7%) showed isolated TP53 alteration and were subjected to a comprehensive analysis.

RESULTS

The average age at diagnosis was 65 years (range 48-79); 9 males and 5 females. All were smokers with an average pack-year of 41 (range 10-70). Nine had metastases, mostly in the brain (n = 2) and pleura (n = 2). After a follow-up period of up to 102 months, 9 died, 4 were alive with disease, and 1 was lost to follow-up. The median survival was 13 months. Most tumors exhibited poor differentiation, composed of solid sheets with moderate to severe atypia, increased mitotic activity, and necrotic background. Half were positive for TTF-1 and showed p53 overexpression. PD-L1 was positive in 6 cases. Most alterations were missense mutations in exons 5-8, and this mutation type was associated with p53 overexpression. Tumors with combined missense mutation and truncated protein had higher PD-L1 expression and significantly shorter overall survival, along with a trend towards an increase in tumor mutational burden (TMB). CEBPA deletion of undetermined significance was the most common copy number alteration.

CONCLUSION

Isolated TP53 mutation was seen in association with smoking, high-grade cytomorphologic features, adverse prognosis, and recurrent CEBPA deletions. These tumors tend to have strong PD-L1 expression and high TMB, suggesting potential benefit from immune checkpoint inhibitors. Hence, the recognition of this molecular group has prognostic and therapeutic implications.

The Significance of RAS-Like Mutations and MicroRNA Profiling in Predicting Malignancy in Thyroid Biopsy Specimens

In cytologically indeterminate thyroid nodules undergoing molecular testing, estimated risk of malignancy is variable. Identification of a non-cancer-specific mutation (RAS-like) confirms a neoplastic process but does not differentiate between benign, malignant, and low-risk neoplasms. This study aims to retrospectively evaluate institutional experience of Interpace (ThyGeNEXT^® and ThyraMIR^®; Pittsburgh, PA) testing and to determine the rate of malignancy in resected nodules, stratified by mutational analysis and microRNA profile. Of 1917 fine need aspirations, 140 (7.3%) underwent Interpace testing: 47 (33.6%) were molecular-not-benign (harbored mutation, fusion, and/or positive miRNA) and 93 (66.4%) were molecular-benign (no mutations or fusions and negative microRNA). Surgery was spared in 79.6% of molecular-benign and 61.4% of all tested patients. Fifty-four (38.6%) underwent resection. Seventeen (89.5%) of the resected molecular-benign were benign and 2 were malignant. Thirteen (37.1%) of the resected molecular-not-benign were benign, 7 (20%) were noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), and 15 (42.9%) were malignant (p < 0.05, negative predictive value (NPV) 89.4-95.6%, positive predictive value (PPV) 22.3-42.8%). Most molecular-not-benign (72.3%) had RAS-like mutation. Twenty-three were resected: 3 were malignant and 7 were NIFTP. Nodules with non-RAS-like mutations (BRAF V600E-like, others) were more likely to be malignant than RAS-like (H/N/KRAS, BRAF K601E) (p < 0.05, NPV 86.9-96.5%, PPV 100%). Most nodules had RAS-like mutations and most were benign or low-risk neoplasms (NIFTP). This study supports the role of histologic examination in the distinction of malignancy in RAS-like thyroid neoplasms and underscores the role of molecular testing in risk stratification, patient counseling, and operative management.

High-risk human papillomavirus testing in cytology aspiration samples from the head and neck part 1: a review of the literature on available testing options

Human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma is increasing in incidence and is often first diagnosed on a cytology fine needle aspiration (FNA) specimen of metastatic nodal disease of the neck. In the setting of oropharyngeal squamous cell carcinoma, HPV status defines the disease with HPV-associated tumors having better overall prognosis than those that are HPV negative. Furthermore, metastatic squamous cell carcinoma of the neck of unknown origin requires testing for HPV as a positive result suggests an oropharyngeal primary. As a result, HPV testing in aspirate samples is increasingly important for the proper diagnosis and treatment of patients with head and neck squamous cell carcinoma. Although HPV testing in cervicovaginal cytology specimens is common and well-established, testing in head and neck FNA samples remains challenging. p16 immunohistochemistry is an excellent surrogate marker for HPV in tumors of known or suspected oropharyngeal origin, but the criteria used in histologic specimens may not be appropriate in cytology samples. FNA samples are more frequently hypocellular, and cytology cell blocks have variable fixation and processing steps, limiting the utility of p16 immunohistochemistry. Other potential testing options have been reported in the literature including staining of aspirate smears and molecular testing of liquid-based samples. The American Society of Cytopathology Clinical Practice Committee recently surveyed the American Society of Cytopathology membership to determine the current state of HPV testing in aspirate samples, and this review article is designed to provide a summary of the current literature on various testing options in FNA samples.

High-risk human papillomavirus testing in cytology aspiration samples from the head and neck part 2: a survey of the American Society of Cytopathology community

INTRODUCTION

High-risk human papillomavirus (HR-HPV) status is critical in the diagnosis of oropharyngeal squamous cell carcinoma, informing prognosis and choice of therapy. HR-HPV status additionally plays a key role in the evaluation of squamous cell carcinoma of unknown origin metastatic to cervical lymph nodes. Thus, HR-HPV testing of fine needle aspirate (FNA) specimens from the head and neck is invaluable for accurate diagnosis, prognostication, and treatment planning.

MATERIALS AND METHODS

American Society of Cytopathology members were surveyed to understand the current state of HR-HPV testing on FNA samples from the head and neck. The survey focused on 3 main topic areas: practice setting of respondents, methods of collection and processing of aspirate specimens for HR-HPV testing, and validation of HR-HPV testing methodologies on aspirate samples.

RESULTS

The survey reveals that laboratories employ various methods to detect HR-HPV in FNA samples, most commonly p16 immunohistochemical staining of cell block sections. Although some laboratories have independently validated their HR-HPV detection method, such validation is not universal. Finally, not all respondents currently have HR-HPV testing available, but approximately half of those without a testing method desire to make HR-HPV testing of FNA samples available.

CONCLUSIONS

Survey responses highlight that various testing modalities are utilized for HR-HPV detection in aspirate samples. However, internal laboratory validation of HR-HPV testing for FNA specimens is not ubiquitous despite professional society recommendations.

Anaplasia and multinucleation in metastases of oropharyngeal squamous cell carcinoma is associated with poorer outcomes

INTRODUCTION

The presence of tumor cell anaplasia and multinucleation (A/M) in oropharyngeal squamous cell carcinoma (OPSCC) has recently been found to be associated with increased disease recurrence and poorer disease-specific survival, regardless of human papillomavirus status. We studied the detection of A/M in cytology specimens.

MATERIALS AND METHODS

We performed a comprehensive data search for all patients with OPSCC diagnosed and treated at Northwestern Memorial Hospital between January 2013 and April 2020. All cytology and histopathologic slides were reviewed for the presence of A/M in patients with both surgical resection or biopsy specimens and fine needle aspiration cytology of a metastatic site.

RESULTS

A total of 87 patients were identified with both surgical and cytology specimens available for review. A/M was identified in 21 cytology specimens and 14 surgical specimens. Cytologic A/M was seen in 11 of the 14 patients (78.5%) with corresponding histologic A/M and in 10 of the 73 patients (13.7%) without histologic A/M. Disease-specific survival was significantly worse for the patients with cytologic A/M regardless of the presence of histologic A/M (P = 0.0064) and for the patients with cytologic A/M only (P = 0.0271). In patients with p16-positive/human papillomavirus-associated carcinoma, disease-specific survival was significantly worse for the patients with both histologic and cytologic A/M (P = 0.0305).

CONCLUSIONS

A/M can be reliably identified in cytology specimens among all the various stains and preparations, irrespective of the primary tumor histologic type. Identification of A/M on cytology specimens could indicate more aggressive clinical behavior and help guide patient management.

Histopathologic and clinical outcomes of Milan System categories "non-diagnostic" and "non-neoplastic" of salivary gland fine needle aspirations

INTRODUCTION

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) specifies six categories with estimated risks of malignancy (ROM) and suggested management. The estimated ROM is 25% for Non-Diagnostic (ND) category, and 10% for Non-Neoplastic (NN). This study aimed to investigate histopathologic and clinical outcomes of MSRSGC categories ND and NN at the authors' institution.

MATERIALS AND METHODS

Cytopathology fine needle aspiration reports from 2008-2020 were searched for the word "salivary", "parotid", and "submandibular". Cases fitting Non-Diagnostic (ND) and Non-Neoplastic (NN) categories were identified. Follow-up cyto-/histopathologic and clinical data were extracted.

RESULTS

There were 43 ND and 46 NN cases. The average age was 58.3 years. Neoplastic lesions were found in 13 of 43 (30%) ND and 3 of 46 (6.5%) NN. The rate of malignancy in ND category was 14.0% (6/43) and 0% (0/46) in NN category. Four cases in ND (9.3%) and 6 (13.0%) in NN had no neoplasm and instead had an underlying reactive condition (e.g., chronic sialadenitis) or inflammatory lesion (e.g., lymphoepithelial cyst) on histologic follow-up. There was no follow-up pathology in 46.5% NDs (20/43) and 82.6% NNs (38/46); however, no lesions were apparent clinically with a mean follow-up of 3 years and 1.5 years, respectively.

CONCLUSIONS

MSRSGC categories ND and NN are helpful for reporting salivary gland FNA results. With proper clinical and radiologic correlation, ROM of NN is low; however, ROM of ND remains significant. Repeat FNA after correlation for ND cases seems prudent as neoplasms and malignancies may have gone undetected.

Oropharyngeal carcinoma: A single institution study of 338 primaries with special reference to high-risk human papillomavirus-mediated carcinoma with aggressive behavior

In a retrospective review, we identified 332 patients with 338 pathologically diagnosed primary oropharyngeal carcinomas (OPC) between January 2013 and March 2020 with known p16/HPV status from a tumor registry at Northwestern Memorial Hospital. The tumors predominantly involved the palatine tonsil (51 %) and the base of the tongue/lingual tonsil (38 %). The most common type of cancer was non-keratinizing squamous cell carcinoma (60 %), and the majority of primaries were p16 positive/HPV-mediated (86 %). A cohort of p16 positive/HPV mediated OPC (27/283, 9.5 %) presented with aggressive clinical behavior, including multiple distant metastases at unusual sites. Tumor size >2 cm and the presence of tumor anaplasia/multinucleation were significantly associated with an increased rate of distant metastases in p16 positive/HPV mediated cases, both in unadjusted and adjusted analyses (all P < 0.05). Of the 332 individuals in the overall cohort, 38 individuals died due to their disease within the observed follow-up time. Among the 283 patients with p16 positive/HPV mediated tumors, survival was estimated at 97 % (95 % CI 95 %, 100 %) at 1 year, 95 % (95 % CI 92 %, 98 %) at 2 years, and 80 % (95 % CI 72 %, 89 %) at 5 years. The presence of tumor anaplasia/multinucleation and distant metastasis were both significantly associated with poorer disease-specific survival in p16 positive/HPV mediated cases (both P < 0.05), with the survival effect of tumor anaplasia/multinucleation likely mediated in part through its association with distant metastasis. For p16 positive/HPV-mediated OPC, age, smoking status, tumor status, and lymph node status were not significantly associated with disease-specific survival in our study.

Results from the 2019 American Society of Cytopathology survey on rapid onsite evaluation (ROSE)-part 2: subjective views among the cytopathology community

INTRODUCTION

This study aims to improve understanding of the cytopathology community's perspective regarding the value of rapid onsite evaluation (ROSE) in clinical practice.

MATERIALS AND METHODS

The American Society of Cytopathology membership was surveyed in 2019 to obtain subjective data on the cytopathology community's perceptions regarding ROSE. Comments were categorized by major themes and attitudes and analyzed by respondent's role in laboratory, practice size, and practice setting (Fisher's exact and χ² tests).

RESULTS

A total of 541 responses were received from 255 cytopathologists/pathologists, 261 cytotechnologists, 19 trainees, and 6 others (as previously reported). Reasons for which cytopathology personnel provide this service aligned with their perceptions of why clinicians request ROSE. A minority of respondents, disproportionally from high volume centers, felt ROSE is unnecessary. Overall attitude regarding ROSE was generally positive. There were no significant differences in attitude regarding ROSE according to role in laboratory or practice size, but respondents from academic centers provided a significantly higher percentage of positive comments than those in private or community practice. Although survey respondents generally felt that ROSE is valuable to patient care, they also highlighted several challenges, including staffing, time commitment, and inadequate reimbursement. Implementation of telecytology was felt to potentially alleviate some of these challenges.

CONCLUSIONS

Survey results show that the cytology community views ROSE favorably, practices vary considerably, and there is a perceived need for improved reimbursement. Data from this study may be used to identify areas that warrant additional research to clarify the clinical value of ROSE.

Cytologic grading of primary malignant salivary gland tumors: A blinded review by an international panel

BACKGROUND

Fine needle aspiration (FNA) is commonly used for the preoperative evaluation of salivary gland tumors. Tumor grade is a key factor influencing clinical management of salivary gland carcinomas (SGCs). To assess the ability to grade nonbasaloid SGCs in FNA specimens, an international panel of cytopathologists convened to review and score SGC cases.

METHODS

The study cohort included 61 cases of primary SGC from the pathology archives of 3 tertiary medical centers. Cases from 2005 to 2016 were selected, scanned, and digitized. Nineteen cytopathologists blinded to the histologic diagnosis reviewed the digitized cytology slides and graded them as low, high, or indeterminate. The panelists' results were then compared to the tumor grades based on histopathologic examination of the corresponding resection specimens.

RESULTS

All but 2 of the 19 (89.5%) expert panelists review more than 20 salivary gland FNAs per year; 16 (84.2%) of the panelists work at academic medical centers, and 13 (68.4%) have more than 10 years' experience. Participants had an overall accuracy of 89.4% in the grading of SGC cases, with 90.2% and 88.3% for low- and high-grade SGC, respectively. Acinic cell carcinoma and mucoepidermoid carcinoma had the highest degree of accuracy, while epithelial-myoepithelial carcinoma and salivary duct carcinoma had the lowest degree of accuracy. As expected, the intermediate-grade SGC cases showed the greatest variability (high-grade, 42.1%; low-grade, 37.5%, indeterminate, 20.4%).

CONCLUSION

This study confirms the high accuracy of cytomorphologic grading of primary SGC by FNA as low- or high-grade. However, caution should be exercised when a grade cannot be confidently assigned.

Simulating microbial processes in extraterrestrial, aqueous environments

Finding evidence of life elsewhere in the Solar System is dependent on understanding biotic processes that could occur within potentially habitable environments. Here, we describe a suite of high-pressure flow-through reactors that have been developed to investigate biotic and abiotic processes within simulated sub-surface martian and icy moon environments.

A Proposal for Separation of Nuclear Atypia and Architectural Atypia in Bethesda Category III (AUS/FLUS) Based on Differing Rates of Thyroid Malignancy

Objectives

Bethesda category III (atypia of undetermined significance/follicular lesion of undetermined significance) includes sparsely cellular specimens with nuclear atypia (3N) and/or architectural atypia (3A). This study investigates whether the two types of atypia have different rates of malignancy (ROMs).

Methods

Cytologic and histologic diagnoses of resected thyroid nodules were recorded. ROM was calculated for all Bethesda categories and for 3N and 3A subcategories. Possible noninvasive follicular thyroid neoplasms with papillary-like nuclear features were reviewed and removed from malignancies, and ROM was recalculated.

Results

A total of 1,396 nodules were included. ROM of 3N (33.3%-26.0%) was higher than 3A (7.7%-5.0%) (P < .0001) and was similar to suspicious for follicular neoplasm (25.0%-20.3%) (P = .3). ROM of 3A approached benign (2.4%-1.5%) (P = .02).

Conclusions

Strong consideration should be given to separating 3N (nuclear atypia with higher risk for papillary thyroid carcinoma) from 3A (architectural atypia with higher chance of being benign) to convey different ROMs.

Dihydropyrimidine dehydrogenase deficiency as a cause of fatal 5-Fluorouracil toxicity

5-Fluorouracil (5-FU), in combination with other cytotoxic drugs, is commonly used to treat a variety of cancers. Dihydropyrimidine dehydrogenase (DPD) catalyzes the first catabolic step of the 5-FU degradation pathway, converting 80% of 5-FU to its inactive metabolite. Approximately 0.3% of the population demonstrate complete DPD deficiency, translating to extreme toxicity of 5-FU. Here we present a case of a patient who had a fatal outcome after treatment with 5-FU who was found to have an unknown DPD deficiency discovered at autopsy.

Multiple simultaneous head and neck cancers in Lynch syndrome: Case report and literature review

Head and neck cancers account for a significant proportion of reported malignancies in the United States; however, multiple concurrent primary malignancies from different sites are rare. We describe the case of a 44-year-old man simultaneously diagnosed with three independent head and neck malignancies (adenocarcinoma in minor salivary gland, papillary thyroid carcinoma, and acinic cell carcinoma) in the setting of Lynch syndrome. To our knowledge, this is the first case of multiple head and neck malignancies arising simultaneously from Lynch syndrome. This case highlights the need for diligent workup in patients with hereditary conditions that predispose to malignancies. Laryngoscope, 128:2759-2761, 2018.

Noninvasive Follicular Thyroid Neoplasms With Papillary-like Nuclear Features Are Genetically and Biologically Similar to Adenomatous Nodules and Distinct From Papillary Thyroid Carcinomas With Extensive Follicular Growth

CONTEXT

- Proposed noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTPs), formerly noninvasive encapsulated papillary carcinoma, follicular variant (PTC-FV), is an indolent tumor with follicular growth and frequent RAS mutations.

OBJECTIVE

- To detect histologic and molecular differences separating NIFTP from follicular adenomas (FAs) and invasive carcinomas, particularly papillary carcinomas with extensive follicular growth (PTC-EFGs) and invasive encapsulated PTC-FV (IE-PTC-FV).

DESIGN

- Sixty-one tumors were reviewed histologically and reclassified into 32 NIFTPs (52%), 4 IE-PTC-FVs (7%), 14 PTC-EFGs (23%), and 11 FAs (18%). Next-generation sequencing for mutations in 50 genes was performed. Clinical outcomes were recorded.

RESULTS

- The NIFTPs and FAs were well circumscribed and unencapsulated. The FAs had bland nuclei, whereas the NIFTPs showed at least 2 of 3 (67%; sufficient) nuclear features (enlargement, irregular contours, chromatin clearing). The IE-PTC-FVs had follicular growth, sufficient nuclear features, and extensive capsular invasion. The PTC-EFGs had a median of 5% papillae with intrathyroidal invasion (broad-based, sclerotic, or small follicle growth patterns); intranuclear pseudoinclusions were present only in PTC-EFGs (9 of 14; 64%). Mutations included RAS in 20 of the 32 NIFTPs (62%), 4 of the 11 FAs (36%), and 3 of the 4 IE-PTC-FVs (75%); BRAF K601E in 1 NIFTP (3%); BRAF V600E in 5 PTC-EFGs (36%). No NIFTPs or FAs recurred or metastasized. All 4 IE-PTC-FVs (100%) had hematogenous metastasis. Two PTC-EFGs (14%) had lymphatic metastasis.

CONCLUSIONS

- The morphologic similarity and RAS mutations in FAs, NIFTPs, and IE-PTC-FVs supports the genetic similarity of those follicular neoplasms in contrast to the unique presence of BRAF V600E mutations in PTC-EFGs. Using strict diagnostic criteria supported by molecular testing, tumors with extensive follicular growth can be classified into follicular type or RAS-like (FA, NIFTP, IE-PTC-FV) versus papillary type or BRAF V600E-like (PTC-EFG).

Arsenic exposure induces glucose intolerance and alters global energy metabolism

Environmental pollutants acting as endocrine-disrupting chemicals (EDCs) are recognized as potential contributors to metabolic disease pathogenesis. One such pollutant, arsenic, contaminates the drinking water of ~100 million people globally and has been associated with insulin resistance and diabetes in epidemiological studies. Despite these observations, the precise metabolic derangements induced by arsenic remain incompletely characterized. In the present study, the impact of arsenic on in vivo metabolic physiology was examined in 8-wk-old male C57BL/6J mice exposed to 50 mg/l inorganic arsenite in their drinking water for 8 wk. Glucose metabolism was assessed via in vivo metabolic testing, and feeding behavior was analyzed using indirect calorimetry in metabolic cages. Pancreatic islet composition was assessed via immunofluorescence microscopy. Arsenic-exposed mice exhibited impaired glucose tolerance compared with controls; however, no difference in peripheral insulin resistance was noted between groups. Instead, early insulin release during glucose challenge was attenuated relative to the rise in glycemia. Despite decreased insulin secretion, pancreatic β-cell mass was not altered, suggesting that arsenic primarily disrupts β-cell function. Finally, metabolic cage analyses revealed that arsenic exposure induced novel alterations in the diurnal rhythm of food intake and energy metabolism. Taken together, these data suggest that arsenic exposure impairs glucose tolerance through functional impairments in insulin secretion from β-cells rather than by augmenting peripheral insulin resistance. Further elucidation of the mechanisms underlying arsenic-induced behavioral and β-cell-specific metabolic disruptions will inform future intervention strategies to address this ubiquitous environmental contaminant and novel diabetes risk factor.

Cytomorphologic features of metastatic endometrioid carcinoma by fine needle aspiration

BACKGROUND

Although metastatic disease is commonly seen in high grade carcinomas of gynecologic origin, it also occurs in low to intermediate grade endometrioid carcinomas (LGEMCAs), and may even be the primary presentation of disease. Tissue confirmation is necessary to guide therapy, but performing biopsies might not always be feasible or practical. In such instances, fine needle aspiration (FNA) is a safe and efficient alternative. No comprehensive series describing the cytomorphologic features of metastatic LGEMCA on FNA samples has been published. This study describes clinical and cytomorphologic features of metastatic LGEMCA diagnosed by FNA.

METHODS

The pathology archives at 2 academic institutions were searched for patients with endometrial or ovarian endometrioid carcinoma, with concurrent or subsequent sampling of metastatic sites by FNA.

RESULTS

Twelve cases were identified; all slides were reviewed and cytomorphologic features recorded. Four cases were obtained from metastatic sites as primary presentation of disease, and 8 cases were obtained from metastatic sites in patients with known history of LGEMCA. Metastatic LGEMCAs generate cellular specimens composed of cohesive clusters of cells with areas of gland formation. Consistent cytomorphologic features included nuclear overlapping, low to intermediate nuclear to cytoplasmic ratios, round to elongated nuclear shape, finely vacuolated cytoplasm, mild to moderate nuclear membrane irregularities, squamous metaplasia, and inconspicuous nucleoli. Variability was seen with regards to the presence of necrosis (50% of cases) and mitosis (25% of cases).

CONCLUSION

The presence of these features on FNA samples should raise concern for an underlying gynecologic malignancy.

Thyroid Nodule Size at Ultrasound as a Predictor of Malignancy and Final Pathologic Size

BACKGROUND

Thyroid-related mortality has remained constant despite the increasing incidence of thyroid carcinoma. Most thyroid nodules are benign; therefore, ultrasound and fine needle aspiration (FNA) are integral in cancer screening. We hypothesize that increased nodule size at ultrasound does not predict malignancy and correlation between nodule size at ultrasound and pathologic exam is good.

METHODS

Resected thyroids with preoperative ultrasounds were identified. Nodule size at ultrasound, FNA diagnosis by Bethesda category, size at pathologic examination, and final histologic diagnosis were recorded. Nodule characteristics at ultrasound and FNA diagnoses were correlated with gross characteristics and histologic diagnoses. Nodules for which correlation could not be established were excluded.

RESULTS

Of 1003 nodules from 659 patients, 26% were malignant. Nodules <2 cm had the highest malignancy rate (∼30%). Risk was similar (∼20%) for nodules ≥2 cm. Of the 548 subject to FNA, 38% were malignant. Decreasing malignancy rates were observed with increasing size (57% for nodules <1 cm to 20% for nodules >6 cm). At ultrasound size cutoffs of 2, 3, 4, and 5 cm, smaller nodules had higher malignancy rates than larger nodules. Of the 455 not subject to FNA, 11% were malignant. Ultrasound size alone is a poor predictor of malignancy, but a relatively good predictor of final pathologic size (R² = 0.748), with less correlation at larger sizes. In nodules subject to FNA, false negative diagnoses were highest (6-8%) in nodules 3-6 cm, mostly due to encapsulated follicular variant of papillary carcinoma.

CONCLUSIONS

Thyroid nodule size is inversely related to malignancy risk, as larger nodules have lower malignancy rates. However, the relationship of size to malignancy varies by FNA status. All nodules (regardless of FNA status) demonstrate a risk trough at ≥2 cm. Nodules subject to FNA show step-wise decline in malignancy rates by size, demonstrating that size alone should not be considered as an independent risk factor. Size at ultrasound shows relatively good correlation with final pathologic size. False negative rates are low in this series. Lesions with the appropriate constellation of clinical and radiographic findings should undergo FNA regardless of size. Both size and FNA diagnosis should influence the clinical decision-making process.

Dietary exposure to the endocrine disruptor tolylfluanid promotes global metabolic dysfunction in male mice

Environmental endocrine disruptors are implicated as putative contributors to the burgeoning metabolic disease epidemic. Tolylfluanid (TF) is a commonly detected fungicide in Europe, and previous in vitro and ex vivo work has identified it as a potent endocrine disruptor with the capacity to promote adipocyte differentiation and induce adipocytic insulin resistance, effects likely resulting from activation of glucocorticoid receptor signaling. The present study extends these findings to an in vivo mouse model of dietary TF exposure. After 12 weeks of consumption of a normal chow diet supplemented with 100 parts per million TF, mice exhibited increased body weight gain and an increase in total fat mass, with a specific augmentation in visceral adipose depots. This increased adipose accumulation is proposed to occur through a reduction in lipolytic and fatty acid oxidation gene expression. Dietary TF exposure induced glucose intolerance, insulin resistance, and metabolic inflexibility, while also disrupting diurnal rhythms of energy expenditure and food consumption. Adipose tissue endocrine function was also impaired with a reduction in serum adiponectin levels. Moreover, adipocytes from TF-exposed mice exhibited reduced insulin sensitivity, an effect likely mediated through a specific down-regulation of insulin receptor substrate-1 expression, mirroring effects of ex vivo TF exposure. Finally, gene set enrichment analysis revealed an increase in adipose glucocorticoid receptor signaling with TF treatment. Taken together, these findings identify TF as a novel in vivo endocrine disruptor and obesogen in mice, with dietary exposure leading to alterations in energy homeostasis that recapitulate many features of the metabolic syndrome.

miR-183-96-182 cluster is overexpressed in prostate tissue and regulates zinc homeostasis in prostate cells

Decreased zinc levels are a hallmark of prostate cancer tumors as zinc uniquely concentrates in healthy prostate tissue. Increased dietary zinc correlates with decreased risk of advanced prostate cancer and decreased mortality from prostate cancer. The mechanisms of prostatic zinc homeostasis are not known. Lower zinc levels in the tumor are correlated directly with decreased expression of the zinc transporter hZIP1. We report identification of a microRNA cluster that regulates multiple zinc transporters, including hZIP1. Screening in laser capture microdissected prostate cancer tumors identified miR-182 as a potential regulator of hZIP1. Regulation of hZIP1 by miR-182 via two binding sites was confirmed in primary prostate cell cultures. miR-96 and miR-183 are expressed as a cluster with miR-182 and share similar sequences. Array profiling of tissue showed that miR-183, -96, and -182 are higher in prostate cancer tissue compared with normal prostate. Overexpression of the entire miR-183-96-182 cluster suppressed five additional zinc transporters. Overexpression of miR-183, -96, and -182 individually or as a cluster diminished labile zinc pools and reduced zinc uptake, demonstrating this miR cluster as a regulator of zinc homeostasis. We observed regulation of zinc homeostasis by this cluster in prostate cells and HEK-293 cells, suggesting a universal mechanism that is not prostate-specific. To our knowledge, this is the first report of a miR cluster targeting a family of metal transport proteins. Individually or as a cluster, miR-183, -96, and -182 are overexpressed in other cancers too, implicating this miR cluster in carcinogenesis.

Environmental endocrine disruptors promote adipogenesis in the 3T3-L1 cell line through glucocorticoid receptor activation

The burgeoning obesity and diabetes epidemics threaten health worldwide, yet the molecular mechanisms underlying these phenomena are incompletely understood. Recently, attention has focused on the potential contributions of environmental pollutants that act as endocrine disrupting chemicals (EDCs) in the pathogenesis of metabolic diseases. Because glucocorticoid signaling is central to adipocyte differentiation, the ability of EDCs to stimulate the glucocorticoid receptor (GR) and drive adipogenesis was assessed in the 3T3-L1 cell line. Various EDCs were screened for glucocorticoid-like activity using a luciferase reporter construct, and four (bisphenol A (BPA), dicyclohexyl phthalate (DCHP), endrin, and tolylfluanid (TF)) were shown to significantly stimulate GR without significant activation of the peroxisome proliferator-activated receptor-gamma. 3T3-L1 preadipocytes were then treated with EDCs and a weak differentiation cocktail containing dehydrocorticosterone (DHC) in place of the synthetic dexamethasone. The capacity of these compounds to promote adipogenesis was assessed by quantitative oil red O staining and immunoblotting for adipocyte-specific proteins. The four EDCs increased lipid accumulation in the differentiating adipocytes and also upregulated the expression of adipocytic proteins. Interestingly, proadipogenic effects were observed at picomolar concentrations for several of the EDCs. Because there was no detectable adipogenesis when the preadipocytes were treated with compounds alone, the EDCs are likely promoting adipocyte differentiation by synergizing with agents present in the differentiation cocktail. Thus, EDCs are able to promote adipogenesis through the activation of the GR, further implicating these compounds in the rising rates of obesity and diabetes.

Altering PPARgamma ligand selectivity impairs adipogenesis by thiazolidinediones but not hormonal inducers

Peroxisome proliferator-activated receptor gamma (PPARgamma) acts as a ligand-dependent transcription factor with a key role in mediating adipocyte differentiation and insulin sensitivity. Recently, we and others have shown that PPARgamma recruits the nuclear corepressors NCoR and silencing mediator for retinoid and thyroid hormone receptors (SMRT) to modulate adipogenesis. While the synthetic ligands for PPARgamma, the thiazolidinediones (TZD), are widely used in the treatment of type 2 diabetes mellitus, the biologically relevant endogenous PPARgamma ligand involved in adipogenesis remains unidentified. To further understand the role of ligand binding and corepressor interaction in PPARgamma-mediated adipogenesis, a mutation was introduced in the ligand-binding domain (LBD) of murine PPARgamma. PPARgammamut was created via two amino acid substitutions known to be major determinants of ligand selectivity among PPAR isotypes, H323Y and R288M. These mutations alter PPARgamma to the corresponding residues of the PPARalpha. Characterizing the in vitro functional properties of this mutant, we show that PPARgammamut preferentially responds to the PPARalpha agonist, WY-14643, over the TZD, pioglitazone. When expressed in 3T3-L1 preadipocytes using recombinant adenovirus, wild-type PPARgamma leads to adipocyte formation with both hormonal and TZD treatment. PPARgammamut blocks the upregulation of adipocyte-specific proteins by TZD, but surprisingly, not by standard hormonal inducers. Our data suggest that TZDs and the purported endogenous ligand do not interact in the same way with the PPARgamma LBD. We propose that the endogenous ligand has distinct properties that allow for promiscuity within the hydrophobic PPAR ligand-binding pocket, yet fosters appropriate cofactor recruitment and release to allow adipogenesis to proceed.