An Overview of Pituitary Neuroendocrine Tumors (PitNET) and Algorithmic Approach to Diagnosis.

The diagnostic algorithm and nomenclature of pituitary neuroendocrine tumors have evolved over the past decade, beginning with simpler categorical schemes focused on histomorphologic features and moving to a more sophisticated lineage-specific categorization. This contemporary overview highlights a multimodal approach to pituitary neuroendocrine tumors with a focus on changes in nomenclature, classification, and subclassification; including, brief comments on treatment, and new guidelines for genetic screening, particularly for young patients with such neoplasms.

Proteoglycan signaling in tumor angiogenesis and endothelial cell autophagy.

The need for more effective cancer therapies is omnipresent as the ever-complex, and highly adaptive, mechanisms of tumor biology allow this disease to elude even the most stringent treatment options. The expanding field of proteoglycan signaling is enticing as a reservoir of potential drug targets and prospects for novel therapeutic strategies. The newest trend in proteoglycan biology is the interplay between extracellular signaling and autophagy fueled by the close link between autophagy and angiogenesis. Here we summarize the most current evidence surrounding proteoglycan signaling in both of these biological processes featuring the well-known suspects, decorin and perlecan, as well as other up-and-coming neophytes in this evolving signaling web.

Metabolic reprogramming of murine cardiomyocytes during autophagy requires the extracellular nutrient sensor decorin.

The extracellular matrix is a master regulator of tissue homeostasis in health and disease. Here we examined how the small, leucine-rich, extracellular matrix proteoglycan decorin regulates cardiomyocyte metabolism during fasting in vivo First, we validated in Dcn-/- mice that decorin plays an essential role in autophagy induced by fasting. High-throughput metabolomics analyses of cardiac tissue in Dcn-/- mice subjected to fasting revealed striking differences in the hexosamine biosynthetic pathway resulting in aberrant cardiac O-ß-N-acetylglycosylation as compared with WT mice. Functionally, Dcn-/- mice maintained cardiac function at a level comparable with nonfasted animals whereas fasted WT mice showed reduced ejection fraction. Collectively, our results suggest that reduced sensing of nutrient deprivation in the absence of decorin preempts functional adjustments of cardiac output associated with metabolic reprogramming.

Decorin-inducible Peg3 Evokes Beclin 1-mediated Autophagy and Thrombospondin 1-mediated Angiostasis.

We previously discovered that systemic delivery of decorin for treatment of breast carcinoma xenografts induces paternally expressed gene 3 (Peg3), an imprinted gene encoding a zinc finger transcription factor postulated to function as a tumor suppressor. Here we found that de novo expression of Peg3 increased Beclin 1 promoter activity and protein expression. This process required the full-length Peg3 as truncated mutants lacking either the N-terminal SCAN domain or the zinc fingers failed to translocate to the nucleus and promote Beclin 1 transcription. Importantly, overexpression of Peg3 in endothelial cells stimulated autophagy and concurrently inhibited endothelial cell migration and evasion from a 3D matrix. Mechanistically, we found that Peg3 induced the secretion of the powerful angiostatic glycoprotein Thrombospondin 1 independently of Beclin 1 transcriptional induction. Thus, we provide a new mechanism whereby Peg3 can simultaneously evoke autophagy in endothelial cells and attenuate angiogenesis.

Endorepellin-evoked Autophagy Contributes to Angiostasis.

Endorepellin, the C-terminal domain of perlecan, is an angiostatic molecule that acts as a potent inducer of autophagy via its interaction with VEGFR2. In this study, we examined the effect of endorepellin on endothelial cells using atomic force microscopy. Soluble endorepellin caused morphological and biophysical changes such as an increase in cell surface roughness and cell height. Surprisingly, these changes were not accompanied by alterations in the endothelial cell elastic modulus. We discovered that endorepellin-induced autophagic flux led to co-localization of mammalian target of rapamycin with LC3-positive autophagosomes. Endorepellin functioned upstream of AMP-activated kinase α, as compound C, an inhibitor of AMP-activated kinase α, abrogated endorepellin-mediated activation and co-localization of Beclin 1 and LC3, thereby reducing autophagic progression. Functionally, we discovered that both endorepellin and Torin 1, a canonical autophagic inducer, blunted ex vivo angiogenesis. We conclude that autophagy is a novel mechanism by which endorepellin promotes angiostasis independent of nutrient deprivation.

Brain metastases of papillary thyroid carcinoma origin are derived from aggressive histologic variants and demonstrate similar adverse morphology in the metastatic lesion.

BACKGROUND: Distant metastases of papillary thyroid carcinoma are exceedingly rare. We analyzed all cases of brain metastases of papillary thyroid cancer at our institution and performed a literature review over the past ten years to identify histologic and molecular features of primary and metastatic tumors. METHODS: Following institutional review board approval, the entire pathology archives at our institution were searched for cases of papillary thyroid carcinoma metastatic to brain. Patient demographics, histologic features of both primary and metastatic tumors, molecular information, and clinical outcomes were investigated. RESULTS: We identified 8 cases of metastatic papillary thyroid carcinoma to brain. The average age at time of diagnosis of metastases was 56.3 years (range: 30-85). Average time from diagnosis of primary thyroid cancer to brain metastasis was 9.3 years (range: 0-24 years). All primary thyroid carcinomas demonstrated aggressive sub-types which were correspondingly seen in brain metastases. Next-generation sequencing revealed the most common mutations were identified in BRAFV600E, NRAS, and AKT1 with one tumor harboring a TERT promoter mutation. Six out of eight patients were deceased at the time of study with an average survival time of 2.3 years (range: 0.17-7 years) following diagnosis of brain metastasis. CONCLUSIONS: Based on our study, it is highly unlikely that a low-risk variant of papillary thyroid carcinoma will metastasize to the brain. Therefore, careful and accurate reporting of the papillary thyroid carcinoma subtype in primary thyroid tumors is warranted. Certain molecular signatures are associated with more aggressive behavior and worse patient outcomes and next-generation sequencing should be performed on metastatic lesions.

THADA-IGF2BP3 fusions detected in fine-needle aspiration specimens of thyroid nodules: An institutional experience.

INTRODUCTION: Though the clinical significance of THADA-IGF2BP3 fusions detected in thyroid nodules preoperatively is still under investigation, the limited literature suggests these lesions are clinically low-risk. METHODS: The pathology archives were searched from 2018 to 2022 for all thyroid nodules with a THADA-IGF2BP3 fusion detected via ThyroSeqV3® analysis. Patient demographics and tumor characteristics were collected. Statistical analyses were performed and p < .05 was considered statistically significant. This study was approved by the institutional review board. RESULTS: The case cohort included 34 thyroid nodules with THADA-IGF2BP3 fusions from 32 patients (average age-56.1 years, range: 30-86, male to female ratio-10:22). The average nodule size was 3.2 cm (range: 1.3-7.3 cm). At the time of biopsy, 21 cases were diagnosed as atypia of undetermined significance/follicular lesion of undetermined significance, 12 as follicular neoplasm/suspicious for follicular neoplasm and 1 as suspicious for malignancy. Surgical resection was performed in 29 patients (13 partial and 16 total thyroidectomies) to give a total of 31 nodules. Papillary thyroid carcinoma was diagnosed in 19/31 (61%) cases. No cases showed extrathyroidal extension or lymphovascular invasion. The remaining cases were considered either a low-risk neoplasm or benign. Four cases of NIFTP on final surgical pathology harbored concurrent incidental papillary thyroid microcarcinoma. One patient had the THADA-IGF2BP3 fusion detected in bilateral nodules. CONCLUSIONS: THADA-IGF2BP3 fusions can occur in malignant, low-risk and benign thyroid neoplasms, where malignant neoplasms show lack of aggressive features. Therefore, such entities can be classified as clinically low risk.

Update on Sinonasal Tract Malignancies.

CONTEXT.­: Sinonasal tract malignancies are rare cancers with frequent morphologic overlap. Given the similar histologic profiles seen in many of these entities, they often present a diagnostic challenge to the practicing pathologist. OBJECTIVE.­: To provide a streamlined algorithm using histologic clues, immunohistochemical profiles, and molecular assays to aid in diagnosis of these lesions. DATA SOURCES.­: Sources were the World Health Organization Tumor Classification, literature review, and institutional experience. CONCLUSIONS.­: Although many sinonasal tract malignancies show similar histology, distinct immunohistochemical and molecular profiles can help parse out differences, thereby facilitating diagnosis for the pathologist.

Unraveling the significance of TSHR mutations in indeterminate thyroid cytology specimens.

OBJECTIVES: We investigated the clinical significance of thyroid-stimulating hormone receptor (TSHR) mutations detected in thyroid fine needle aspiration (FNA) specimens. METHODS: The pathology archives at our institution were reviewed between 2018 and 2021 for indeterminate (Bethesda category III and IV) specimens with Thyroseq® analysis showing TSHR mutations. RESULTS: A total of 2184 cases diagnosed as atypia/follicular lesion of undetermined significance (AUS/FLUS), and 2625 diagnosed as follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) were identified. A total of 1735 AUS/FLUS and 2339 SFN/FN underwent Thyroseq® analysis; 69 showed TSHR mutations (1.6%, 59 female, 10 male, average age: 55 years). Ten cases showed oncocytic features. Twelve patients underwent radionuclide scans within 1 year of FNA:11 were hyperfunctioning. Nodule size and TSH levels were weakly correlated. Twenty-two different TSHR mutations were identified (most common: M453T). A second mutation was found in five cases (EZH1 n = 2, and EIF1AX n = 3). The expression of sodium-iodide transporter (NIS) mRNA was in the range of 0.01%-62.43% out of all sequencing reads, and was elevated in 49 (71%) cases. Surgical pathology follow-up was available in five cases (all benign except one). On follow-up available for 38 cases (mean: 24 months; range: 7-47 months), 34 (89.5%) nodules remained stable and 3 (8%) increased in size. CONCLUSIONS: TSHR mutations in thyroid FNA samples classified as indeterminate are rare, generally benign, and commonly associated with autonomy on scan if performed.

Does the presence of capsule influence prognosis in poorly differentiated thyroid carcinoma?

We collected all cases of poorly differentiated thyroid carcinoma at our institution diagnosed between 2007 and 2022 to investigate the role of tumor capsule in these neoplasms along with other histologic factors that may lead to adverse patient outcomes. After the exclusion of those meeting criteria for differentiated high-grade thyroid carcinoma or anaplastic carcinoma, we were left with 65 cases with a poorly differentiated component. Four of those cases (6.2%) were entirely encapsulated with no invasion of the tumor capsule. Unencapsulated tumors showed significantly greater rates of extrathyroidal extension (75.0% versus 41.5%) and death from disease (45.5% versus 12.5%) than encapsulated tumors, regardless of capsular invasion, with no differences in sex, tumor size, angioinvasion, local recurrence, or metastasis. Compared with encapsulated tumors with invasion, encapsulated tumors without capsular invasion showed a strong male predominance (100% versus 38.8%). No encapsulated tumors without capsular invasion demonstrated local recurrence, metastasis, or death from disease. No differences in the percentage of poorly differentiated components were noted among the 3 groups, although there was a trend for encapsulated tumors to have a higher percentage of poorly differentiated components than unencapsulated tumors. We conclude that invasive tumors lacking a capsule demonstrate greater rates of disease-related death despite showing similar adverse histologic features to invasive encapsulated tumors. Moreover, we confirm that encapsulated tumors without capsular invasion have excellent long-term outcomes in terms of recurrences, metastases, and survival.

Carcinoma Ex Pleomorphic Adenomas: An Institutional Experience and Literature Review.

OBJECTIVES: To provide an institutional experience with cases diagnosed as carcinoma ex pleomorphic adenoma (CXPA), including the cytologic and histologic findings and clinical follow-up, followed by a comparison to the experience documented in the literature. METHODS: We identified cases of CXPA diagnosed at our institution from 2011 to 2021 and reviewed the cytologic and histologic diagnoses, as well as the treatment and clinical outcomes. Additionally, a literature review of the English literature was performed on CXPAs from 2011 to 2021. RESULTS: Forty-one cases of CXPA were identified, with the majority subclassified as adenocarcinoma, not otherwise specified. Five tumors underwent cytogenetic studies and five underwent molecular studies. To date, 36 patients are alive, 8 of whom experienced locoregional recurrence or distant metastasis. CONCLUSIONS: Our institutional experience was comparable to that reported in the literature. Further studies are required to inquire about the role of molecular profiles of CXPAs in clinical risk assessment.

Clinical Evaluation of IDH Mutation Status in Formalin-Fixed Paraffin-Embedded Tissue in Gliomas.

BACKGROUND AND OBJECTIVE: Determination of isocitrate dehydrogenase (IDH) 1/2 mutational status is crucial for a glioma diagnosis. It is common for IDH mutational status to be determined via a two-step algorithm that utilizes immunohistochemistry studies for IDH1 R132H, the most frequent variant, followed by next-generation sequencing studies for immunohistochemistry-negative or immunohistochemistry-equivocal cases. The objective of this study was to evaluate adding a rapid real-time polymerase chain reaction (RT-PCR) assay to the testing algorithm.  METHODS: We validated a modified, commercial, qualitative, RT-PCR assay with the ability to detect 14 variants in IDH1/2 in formalin-fixed paraffin-embedded glioma tumor specimens. The assay was validated using 51 tumor formalin-fixed paraffin-embedded specimens. During clinical implementation of this assay, 48 brain tumor specimens were assessed for IDH result concordance and turnaround time to result. RESULTS: Concordance between the RT-PCR and sequencing and IHC studies was 100%. This RT-PCR assay also showed concordant results with IHC for IDH1 R132H for 11 of the 12 (92%) tumor specimens with IDH mutations. The RT-PCR assay yielded faster results (average 2.6 days turnaround time) in comparison to sequencing studies (17.9 days), with complete concordance. CONCLUSIONS: In summary, we report that this RT-PCR assay can reliably be performed on formalin-fixed paraffin-embedded specimens and has a faster turnaround time than sequencing assays and can be clinically implemented for determination of IDH mutation status for patients with glioma.

A Cyst-ematic Analysis of the Adrenal Gland: A Compilation of Primary Cystic Lesions From Our Institution and Review of the Literature.

OBJECTIVES: Although primary adrenal lesions and metastases are most commonly encountered, de novo cysts of the adrenal gland can occasionally occur. METHODS: We analyzed the pathology archives at the Hospital of the University of Pennsylvania for diagnoses of cystic lesions of the adrenal gland between 1998 and 2020. Patient demographics and clinical information were extracted, and pathology slides and stains, as appropriate, were analyzed. The literature between 1998 and 2020 was also searched for large case series involving cystic adrenal lesions. RESULTS: We found 18 cystic lesions of the adrenal gland in our archives, categorized as pseudocysts (7), endothelial cysts (5), mesothelial cysts (2), mature teratoma (1), cystic adrenal cortical adenoma (1), cystic pheochromocytoma (1), and cystic metastasis (1). The mean age at time of diagnosis was 52.3 years, and the mean size of the cysts was 6.0 cm. There was a slight female predilection, and cysts were more likely to be found on the left side. All lesions were incidental findings. The cystic metastasis was clear cell renal cell carcinoma. Our findings were also compared with those found in the literature published within the same timeframe. CONCLUSIONS: Adrenal cysts are rare entities. Our findings are concordant with other large studies and provide additional cases to the existing literature. In addition, our literature search expands the possible differential diagnoses for cystic lesions arising in the adrenal gland.

Papillary thyroid microcarcinomas: does subtyping predict aggressive clinical behavior?

The most common malignant neoplasm affecting the thyroid gland is papillary thyroid carcinoma (PTC). PTC can demonstrate a number of morphologic variants including, but not limited to, classic, follicular, and tall cell. Each of these morphologic subtypes carry distinct clinical characteristics such that certain variants, like tall cell, behave more aggressively than others. PTCs measuring less than or equal to 1.0 cm are classified as microcarcinomas. Although these lesions are thought to be clinically indolent, we hypothesized that, like their larger counterparts, certain histologic variants may lead to worse patient outcomes. To test our hypothesis, we analyzed our pathology archives between the years 2009 and 2020 for papillary thyroid microcarcinomas and assessed whether different morphologic features correlated with more aggressive clinical behavior. Our findings suggest that certain variants exhibit features that portend a more worrisome clinical course and thus papillary thyroid microcarcinomas should be subtyped to help predict patient outcome.

A contemporary update on hyalinizing clear cell carcinoma: compilation of all in-house cases at our institution and a literature review spanning 2015-2020.

Tumors of the head and neck with clear cell features prompt a broad differential diagnosis. A relatively uncommon, but increasingly recognized, entity is hyalinizing clear cell carcinoma (HCCC). This neoplasm, first described in 1994, consists of clear cells arranged in nests or trabecule with a hyalinized stroma. These are low-grade neoplasms that only infrequently metastasize and rarely recur. They also often harbor a unique EWSR-ATF1 gene rearrangement. As the prognosis is excellent compared with other clear cell neoplasms, the correct diagnosis is key. Here we present all of the cases of HCCC in the past decade from our institution alongside a comprehensive literature review spanning 2015-2020 to further characterize this unusual malignancy.

An improved phenylarsine oxide-affinity method identifies triose phosphate isomerase as a candidate redox receptor protein.

Reversible oxidation on proteins of vicinal thiols to form intraprotein disulfides is believed to be an important means by which redox sensitivity is conferred on cellular signaling and metabolism. Affinity chromatography using immobilized phenylarsine oxide (PAO), which binds preferentially to vicinal thiols over monothiols, has been used in very limited studies to isolate the fraction of cellular proteins that exhibit reversible oxidation of vicinal thiols to presumed disulfide bonds. A challenge to the use of PAO-affinity chromatography for isolation of readily oxidizable vicinal thiol proteins (VTPs) has been the lack of a disulfide reducing agent that reverses oxidation of the PAO-binding protein thiols and maintains these in the reduced state necessary to bind PAO but does not also compete with the VTPs for binding to the immobilized PAO. The present study demonstrates that the capture from a detergent-soluble rat brain extract of VTPs by PAO-affinity chromatography was improved greatly by use of the reducing agent tris(2-carboxyethyl)-phosphine which, unlike more traditional disulfide-reducing agents, does not contain a thiol group. Moreover, we show that, while a substantial fraction of total brain proteins contain PAO-binding thiols, only a fraction of these were readily and reversibly oxidized. The two most abundant of these redox-active proteins were identified as albumin and triose phosphate isomerase (TPI). We propose that TPI is a candidate intracellular redox receptor protein. The improved PAO-affinity method detailed here should enable the discovery of lower abundance novel redox-active regulatory proteins.

Autophagic degradation of HAS2 in endothelial cells: A novel mechanism to regulate angiogenesis.

Hyaluronan plays a key role in regulating inflammation and tumor angiogenesis. Of the three transmembrane hyaluronan synthases, HAS2 is the main pro-angiogenic enzyme responsible for excessive hyaluronan production. We discovered that HAS2 was degraded in vascular endothelial cells via autophagy evoked by nutrient deprivation, mTOR inhibition, or pro-autophagic proteoglycan fragments endorepellin and endostatin. Using live-cell and super-resolution confocal microscopy, we found that protracted autophagy evoked a dynamic interaction between HAS2 and ATG9A, a key transmembrane autophagic protein. This regulatory axis of HAS2 degradation occurred in various cell types and species and in vivo upon nutrient deprivation. Inhibiting in vivo autophagic flux via chloroquine showed increased levels of HAS2 in the heart and aorta. Functionally, autophagic induction via endorepellin or mTOR inhibition markedly suppressed extracellular hyaluronan production in vascular endothelial cells and inhibited ex vivo angiogenic sprouting. Thus, we propose autophagy as a novel catabolic mechanism regulating hyaluronan production in endothelial cells and demonstrate a new link between autophagy and angiogenesis that could lead to potential therapeutic modalities for angiogenesis.

Extracellular matrix: The driving force of mammalian diseases.

Like the major theme of a Mozart concerto, the immense and pervasive extracellular matrix drives each movement and ultimately closes the symphony, embracing a unique role as the fundamental mediator for most, if not all, ensuing intracellular events. As such, it comes as no surprise that the mechanism of just about every known disease can be traced back to some part of the matrix, typically in the form of an abnormal amount or activity level of a particular matrix component. These defects considerably affect downstream signaling axes leading to overt cellular dysfunction, organ failure, and death. From skin to bone, from vessels to brain, from eyes to all the internal organs, the matrix plays an incredible role as both a cause and potential means to reverse diseases. Human malaises including connective tissue disorders, muscular dystrophy, fibrosis, and cancer are all extracellular matrix-driven diseases. The ability to understand and modulate these matrix-related mechanisms may lead to the future discovery of novel therapeutic options for these patients.