Sarcomatoid and Rhabdoid Renal Cell Carcinoma: Clinical, Pathologic, and Molecular Genetic Features.

Renal cell carcinoma (RCC) with sarcomatoid and rhabdoid morphologies has an aggressive biological behavior and a typically poor prognosis. The current 2022 WHO classification of renal tumors does not include them as distinct histologic entities but rather as transformational changes that may arise in a background of various distinct histologic types of RCC. The sarcomatoid component shows malignant spindle cells that may grow as intersecting fascicles, which is reminiscent of pleomorphic undifferentiated sarcoma. The rhabdoid cells are epithelioid cells with eccentrically located vesicular nuclei with prominent nucleoli and large intracytoplasmic eosinophilic inclusions. Studies have shown that RCCs with sarcomatoid and rhabdoid differentiation have distinctive molecular features. Sarcomatoid RCC harbors shared genomic alterations in carcinomatous and rhabdoid components, but also enrichment of specific genomic alterations in the sarcomatoid element, suggesting molecular pathways for development of sarcomatoid growth from a common clonal ancestor. Rhabdoid differentiation also arises through clonal evolution although less is known of specific genomic alterations in rhabdoid cells. Historically, treatment has lacked efficacy, although recently immunotherapy with PD-1/PD-L1/CTLA-4 inhibitors has produced significant clinical responses. Reporting of sarcomatoid and rhabdoid features in renal cell carcinoma is required by the College of American Pathologists and the International Collaboration on Cancer Reporting. This manuscript reviews the clinical, pathologic, and molecular features of sarcomatoid RCC and rhabdoid RCC with emphasis on the morphologic features of these tumors, significance of diagnostic recognition, the molecular mechanisms of tumorigenesis and differentiation along sarcomatoid and rhabdoid lines, and advances in treatment, particularly immunotherapy.

Cytologic evaluation of upper urinary tract specimens: An institutional retrospective study using The Paris System for Reporting Urine Cytology second edition with histopathologic follow-up.

OBJECTIVE: Cytologic evaluation of the upper urinary tract (UUT) can be challenging due to instrumentation artefacts. This study retrospectively reviewed UUT specimens using The Paris System for Reporting Urinary Cytopathology, second edition (TPS 2.0), compared it with the original reporting system (ORS) and correlated it with histopathologic follow-up. METHODS: An institutional database was reviewed for the UUT biopsy/resection histopathologic specimens, and we included 52 UUT cytology specimens pertinent to these cases in the study. These specimens were blindly reviewed and reclassified using TPS 2.0. The correlation between TPS 2.0, ORS and histopathologic follow-up was assessed. RESULTS: The UUT cytology specimens corresponded to 21 (40.4%) high-grade urothelial carcinoma (HGUC), 27 (51.9%) low-grade urothelial carcinoma (LGUC) and 4 (7.7%) benign cases on follow-up. For HGGC cases, the associated TPS categories included unsatisfactory (n = 1, 4.8%), negative for HGUC (NHGUC; n = 3, 14.3%), atypical urothelial cells (AUC; n = 6, 28.6%), suspicious for HGUC (SHGUC; n = 3, 14.3%) and HGUC (n = 8, 38.1%), while ORS categorised the specimens as unsatisfactory (n = 1, 4.8%), negative for malignant cells (NFMC; n = 3, 14.3%), AUC (n = 5, 23.8%), low-grade urothelial carcinoma (LGUC; n = 0, 0%), SHGUC (n = 5, 23.8%) and HGUC (n = 7, 33.3%). The risks of high-grade malignancy among cytologic categories were similar between ORS and TPS (p > 0.05). The majority of LGUC were classified as AUC similarly by ORS and TPS (55.6% vs. 59.3%). CONCLUSIONS: Our study demonstrated comparable performance between TPS 2.0 and ORS for UUT cytology specimens. Cytological diagnosis of UUT specimens remains challenging, especially for LGUC.

Immune dysfunction revealed by digital spatial profiling of immuno-oncology markers in progressive stages of renal cell carcinoma and in brain metastases.

BACKGROUND: The tumor microenvironment (TME) contributes to cancer progression and treatment response to therapy, including in renal cell carcinoma (RCC). Prior profiling studies, including single-cell transcriptomics, often involve limited sample sizes and lack spatial orientation. The TME of RCC brain metastases, a major cause of morbidity, also remains largely uncharacterized. METHODS: We performed digital spatial profiling on the NanoString GeoMx platform using 52 validated immuno-oncology markers on RCC tissue microarrays representing progressive stages of RCC, including brain metastases. We profiled 76 primary tumors, 27 adjacent histologically normal kidney samples, and 86 metastases, including 24 brain metastases. RESULTS: We observed lower immune checkpoint (TIM-3 and CTLA-4), cytolytic (GZMA and GZMB), and T cell activation (CD25) protein expression in metastases compared with primary tumors in two separate cohorts. We also identified changes in macrophages in metastases, with brain metastases-susceptible patients showing less M1-like, inflammatory macrophage markers (HLA-DR and CD127) in metastatic samples. A comparison of brain metastases to extracranial metastases revealed higher expression of the anti-apoptotic, BCL-2-family protein BCL-XL and lower expression of the innate immune activator STING in brain metastases. Lower TIM-3 and CD40 in the TME of brain metastases appear to be associated with longer survival, a finding that requires further validation. CONCLUSIONS: Compared with primary tumors, RCC metastases, including brain metastases, express lower levels of numerous markers of immune activation and current or investigational therapeutic targets. Our findings may have important implications for designing future biomarker and treatment studies and may aid in development of brain metastases-specific therapies.

Utility of parathyroid hormone immunocytochemistry in fine needle aspiration diagnosis of parathyroid tissue.

OBJECTIVE: The cytomorphological features of parathyroid tissue (PTT) may overlap with those of thyroid lesions, thus posing a diagnostic challenge. In this retrospective study, we reviewed our institutional experience in using parathyroid hormone (PTH) immunocytochemistry (ICC) to substantiate the diagnosis of PTT on fine needle aspiration (FNA). METHODS: Our pathology database was searched for FNA cases in which PTH ICC was performed between 1 January 2015 and 31 March 2022. PTH ICC was performed on a ThinPrep slide in cases with a clinical suspicion of PTT or with cytomorphological features raising the possibility of PTT. Patients' clinicopathological characteristics, PTH ICC results, cytological diagnoses, and surgical follow-ups, if available, were reviewed and analysed. RESULTS: The study cohort included 103 cases clinically designated as thyroid (n = 85, 82.5%), parathyroid (n = 11, 10.7%) and neck soft tissue (n = 7, 6.8%). PTH immunostaining was negative, positive, and indeterminate in 53 (51.5%), 27 (26.2%), and 23 (22.3%) cases, respectively. Surgical follow-up was available in 27 (26.2%) cases, including 17 thyroid lesions and 10 PTT cases. All positive PTH cases were confirmed to be PTT, while all but one of the negative PTH cases were non-PTT on follow-up. The calculated sensitivity, specificity, positive and negative predictive values were 85.7%, 100%, 100% and 93.3%, respectively. CONCLUSION: Our study demonstrates that PTH ICC performed on additional ThinPrep slides is a valuable adjunct test in FNA samples with a differential diagnosis of PTT vs non-PTT. Low cellularity may be a limiting factor in the accurate assessment of PTH by ICC.

FGF-21 Conducts a Liver-Brain-Kidney Axis to Promote Renal Cell Carcinoma.

Metabolic homeostasis is one of the most exquisitely tuned systems in mammalian physiology. Metabolic homeostasis requires multiple redundant systems to cooperate to maintain blood glucose concentrations in a narrow range, despite a multitude of physiological and pathophysiological pressures. Cancer is one of the canonical pathophysiological settings in which metabolism plays a key role. In this study, we utilized REnal Gluconeogenesis Analytical Leads (REGAL), a liquid chromatography-mass spectrometry/mass spectrometry-based stable isotope tracer method that we developed to show that in conditions of metabolic stress, the fasting hepatokine fibroblast growth factor-21 (FGF-21)1,2 coordinates a liver-brain-kidney axis to promote renal gluconeogenesis. FGF-21 promotes renal gluconeogenesis by enhancing ß2 adrenergic receptor (Adrb2)-driven, adipose triglyceride lipase (ATGL)-mediated intrarenal lipolysis. Further, we show that this liver-brain-kidney axis promotes gluconeogenesis in the renal parenchyma in mice and humans with renal cell carcinoma (RCC). This increased gluconeogenesis is, in turn, associated with accelerated RCC progression. We identify Adrb2 blockade as a new class of therapy for RCC in mice, with confirmatory data in human patients. In summary, these data reveal a new metabolic function of FGF-21 in driving renal gluconeogenesis, and demonstrate that inhibition of renal gluconeogenesis by FGF-21 antagonism deserves attention as a new therapeutic approach to RCC.

Germline genetic variants are associated with development of insulin-dependent diabetes in cancer patients treated with immune checkpoint inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have dramatically improved survival in patients with cancer but are often accompanied by severe immune-related adverse events (irAEs), which can sometimes be irreversible. Insulin-dependent diabetes is a rare, but life-altering irAE. Our purpose was to determine whether recurrent somatic or germline mutations are observed in patients who develop insulin-dependent diabetes as an irAE. METHODS: We performed RNA and whole exome sequencing on tumors from 13 patients who developed diabetes due to ICI exposure (ICI-induced diabetes mellitus, ICI-DM) compared with control patients who did not develop diabetes. RESULTS: In tumors from ICI-DM patients, we did not find differences in expression of conventional type 1 diabetes autoantigens, but we did observe significant overexpression of ORM1, PLG, and G6PC, all of which have been implicated in type 1 diabetes or are related to pancreas and islet cell function. Interestingly, we observed a missense mutation in NLRC5 in tumors of 9 of the 13 ICI-DM patients that was not observed in the control patients treated with the same drugs for the same cancers. Germline DNA from the ICI-DM patients was sequenced; all NLRC5 mutations were germline. The prevalence of NLRC5 germline variants was significantly greater than the general population (p=5.98×10-6). Although NLRC5 is implicated in development of type 1 diabetes, germline NLRC5 mutations were not found in public databases from patients with type 1 diabetes, suggesting a different mechanism of insulin-dependent diabetes in immunotherapy-treated patients with cancer. CONCLUSIONS: Validation of the NLRC5 mutation as a potential predictive biomarker is warranted, as it might improve patient selection for treatment regimens. Furthermore, this genetic alteration suggests potential mechanisms of islet cell destruction in the setting of checkpoint inhibitor therapy.

Diagnosis of acinic cell carcinoma of the salivary gland on cytology specimens: Role of NOR-1 (NR4A3) immunohistochemistry.

OBJECTIVES: Acinic cell carcinoma (AcCC) is often a challenging diagnosis on cytology. Recently, NOR-1 (NR4A3) has been demonstrated as a sensitive and specific marker for AcCC. Therefore, we conducted this study to evaluate NOR-1 expression in AcCC cytology specimens and to compare its reactivity in other salivary gland tumours (non-AcCC). METHODS: We retrospectively reviewed our database and selected cytology cases with available cell blocks, including 10 AcCC and 24 non-AcCC tumours (12 benign tumours and 12 malignant tumours). NOR-1 (1:50 dilution; SC393902 [H-7]; Santa Cruz Biotech) immunohistochemistry (IHC) was performed on all cases. RESULTS: All AcCC cases except two (2/10, 80%) showed positive nuclear staining of variable intensity for NOR-1, with the majority of cases (75%) demonstrating at least moderately intense nuclear expression. All non-AcCC cases were negative for NOR-1, demonstrating a specificity of 100%. CONCLUSION: We conclude that NOR-1 IHC is sensitive and very specific on cytology specimens and is able to distinguish AcCC from its mimickers reliably and classify them appropriately for further management.

Location matters: LAG3 levels are lower in renal cell carcinoma metastatic sites compared to primary tumors, and expression at metastatic sites only may have prognostic importance.

While great strides have been made in the treatment of advanced renal cell carcinoma (RCC) with the emergence of immune checkpoint inhibitors (ICIs) and VEGFR-targeting drugs, sizable proportions of patients still do not respond to upfront therapy and long-term responses only occur in a minority of patients. There is therefore a great need for the development of better predictors of response and an increased understanding of mechanisms of resistance to these therapies. Alternative immune checkpoints outside the PD-1/PD-L1 axis, such as LAG3, have been implicated as one mechanism of resistance to ICIs. These checkpoints thus represent attractive therapeutic targets, and indeed the LAG3 inhibitor relatlimab was recently approved for the treatment of metastatic melanoma in combination with anti-PD-1 therapy. LAG3 inhibitors are being evaluated for RCC as well. In this context, a better understanding of LAG3 expression patterns in RCC and how they relate to clinicopathologic features of disease and response to immunotherapy may give insight into mechanisms of resistance to PD-1 inhibitors and aid in the identification of subgroups of patients more likely to benefit from certain drug regimens. In this study, we assessed LAG3 protein levels in leukocytes in normal kidney adjacent to RCC, primary RCC tumors, and matched metastatic tumors, including large numbers of brain metastases. We found that LAG3 protein levels are on average lower at metastatic sites compared to matched primary tumors, and that the difference was more pronounced in patients with high-risk clinical characteristics, including those with larger primary tumor size, grade 4 tumors, IMDC poor-risk disease, and initial presentation with brain metastases. We further saw that the prognostic value of LAG3 levels varies depending on the tissue site queried (i.e., primary tumor versus metastases), and that relatively higher LAG3 levels at metastatic sites may predict a better response to immunotherapy and longer overall survival after the development of metastatic disease. These findings may have important implications for the design of future studies involving LAG3 or other immunotherapies in RCC.

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.

Coupled fibromodulin and SOX2 signaling as a critical regulator of metastatic outgrowth in melanoma.

We aimed to study mechanisms controlling metastatic outgrowth of melanoma into clinically relevant lesions, a critical process responsible for the majority of melanoma deaths. To this end, we developed novel in vivo models and identified molecular events that can be ascribed to their distinct phenotypes, indolent or highly metastatic. Induction of a proliferative state at distant sites was associated with high levels of the stem-like/progenitor marker, SOX2, and required the upregulation of FMOD, an extracellular matrix component, which modulates tumor-stroma interactions. Functional studies revealed a possible link between FMOD and SOX2; dual FMOD and SOX2 silencing nearly abolished brain metastasis and had a similar effect on distant metastasis to other sites. Our in vitro data suggests that FMOD and SOX2 cooperation plays an important role in tumor vasculogenic mimicry. Furthermore, we found that FMOD and SOX2 functional roles might converge at the activation of transcriptional co-factors YAP and TAZ, possibly via crosstalk with the tumor suppressor Hippo pathway. Finally, high expression of both genes in patient specimens predicted early development of brain metastasis. Thus, our study identifies FMOD and SOX2 cooperation as a novel regulatory mechanism that might be linked functionally to melanoma metastatic competence.

Evaluation of TRPS1 Expression in Pleural Effusion Cytology Specimens With Metastatic Breast Carcinoma.

OBJECTIVES: Recent studies have shown that trichorhinophalangeal syndrome type 1 (TRPS1) is a sensitive and specific marker that shows positive staining in breast carcinoma. We conducted this study to evaluate the role of TRPS1 immunohistochemistry (IHC) in differentiating breast primary vs tumors from other primary sites in malignant pleural effusion cytology specimens (MPECSs). METHODS: We selected 61 MPECS cases with cell block material available to analyze TRPS1 IHC staining. Of these 61 cases, 38 cases were metastatic carcinoma (MC) from a breast primary. We primarily selected MC cases confirmed as breast origin based on GATA binding protein 3 IHC positivity, except in two of the cases. The remaining 23 MPECS cases were from various primary sites, including urothelial (n = 6), Müllerian (n = 6), lung adenocarcinoma (n = 6), malignant melanoma (MM; n = 3), and squamous cell carcinoma (SqCC; n = 2). RESULTS: TRPS1 expression was observed in 35 (92%) of 38 MCs of breast origin. The staining intensity was variable, with 18 (47%) cases showing strong nuclear expression. In comparison, no TRPS1 expression was seen in any cases of urothelial carcinoma, MM, and SqCC. However, four of six Müllerian MC cases demonstrated TRPS1 expression. CONCLUSIONS: TRPS1 is a new marker that can be used in an IHC panel to investigate breast origin in MPECS.

Copy number variations identified in thyroid FNA specimens are associated with Hürthle cell cytomorphology.

BACKGROUND: The fine-needle aspiration (FNA) diagnosis of thyroid Hürthle cell neoplasms (HCNs) remains challenging. This study explored a possible association of copy number variations (CNVs) with Hürthle cell lesions of the thyroid. METHODS: Thyroid FNA cases that were diagnosed as follicular lesion of undetermined significance (FLUS) or follicular neoplasm (FN)/HCN for which the ThyroSeq version 3 genomic classifier test was performed were retrieved. RESULTS: A total of 324 thyroid FNA cases (228 FLUS cases, 46 HCN cases, and 50 FN cases) were included in the study. FLUS cases were further classified as Hürthle cell type (follicular lesion of undetermined significance-Hürthle cell type [FLUS-HCT]; 20 cases) or non-Hürthle cell type (follicular lesion of undetermined significance-non-Hürthle cell type [FLUS-NHCT]; 208 cases). HCN and FLUS-HCT cases showed a higher prevalence of CNVs (23 of 66 [35%]) in comparison with those classified as FN or FLUS-NHCT (14 of 258 [5%]; P < .001). A total of 105 patients had histopathologic follow-up. Cases with CNVs were more likely to be neoplastic (18 of 26 [69%]) and associated with Hürthle cell changes (14 of 26 [54%]) in comparison with cases without any molecular alterations (neoplastic, 8 of 24 [33%]; Hürthle cell changes, 2 of 24 [8%]; P < .05). In HCN/FLUS-HCT cases with CNVs (n = 14), Hürthle cell changes (13 of 14 [93%]) and neoplasms (9 of 14 [64%]) were more likely to be seen on surgical follow-up in comparison with the 17 cases without CNVs (Hürthle cell changes, 6 of 17 [35%]; neoplastic, 3 of 17 [18%]; P < .05). CONCLUSIONS: CNVs identified in thyroid FNA cases are associated with Hürthle cell morphology and are suggestive of a neoplasm with Hürthle cell features in thyroid FNAs classified as FLUS-HCT/HCN. This finding may be helpful in triaging patients who would benefit from surgical management.

Clinicopathological Review of Micropapillary Urothelial Carcinoma.

PURPOSE OF REVIEW: This review will discuss micropapillary urothelial carcinoma with respect to biology, histopathologic characteristics, genetic and molecular features, diagnosis, clinical management, and future directions of research. RECENT FINDINGS: Recent consensus opinion study showed only moderate interobserver reproducibility in the diagnostic criteria. The most reproducible criteria with the highest consensus were multiple nests in the same lacunar spaces. There are recent reports of high rates of intratumoral heterogeneity of ERBB2 amplification within tumor containing both micropapillary and classic urothelial components. Micropapillary urothelial carcinoma is a well-documented highly aggressive variant of urothelial carcinoma with proven worse outcomes. Accurate recognition and reporting of this pattern is critical for optimal management. Newer therapeutic strategies related to the molecular and genetic findings seen in MPUC remain to be explored further.

RAS mutation and associated risk of malignancy in the thyroid gland: An FNA study with cytology-histology correlation.

BACKGROUND: Activating point mutations of the RAS gene (NRAS, HRAS, and KRAS) can be seen in benign and malignant thyroid tumors; among these, NRAS mutations are more commonly seen. This study was conducted to evaluate the thyroid risk of malignancy (ROM) associated with RAS mutations in thyroid fine-needle aspiration (FNA) at the authors' institution. METHODS: The authors searched their electronic database system between January 2015 and May 2021 for thyroid FNA cases with any type of RAS mutation. Molecular alterations were identified with the ThyroSeq Genomic Classifier, ThyGeNEXT (thyroid oncogene panel)/ThyraMIR (miRNA classifier), or ThyroSure gene panel. RESULTS: A total of 127 cases (age, 51 ± 14 years; 100 females and 27 males) were identified, and 72 had histologic follow-up. The overall ROM associated with RAS mutations (with or without any other molecular alterations) was 29%, whereas the ROM was lower (18%) with RAS mutations only. Isolated NRAS, HRAS, and KRAS mutation-associated ROMs were 15%, 27%, and 14%, respectively. Among these RAS-mutated cases, the cases with a Bethesda category IV cytologic diagnosis had a higher ROM than the cases with a category III diagnosis (38% vs 17%). Twenty-one histologically confirmed malignant cases were mostly classified on cytology as category IV lesions (14 of 34; 41%), and the remainder were either category III (6 of 35; 17%) or V lesions (1 of 1; 100%). CONCLUSIONS: This study demonstrated that the overall RAS mutation-associated ROM in thyroid FNA was intermediate (29%), and isolated HRAS mutations appeared to have a higher ROM (27%) than NRAS and KRAS mutations (15% and 14%, respectively).

Impact of Transoral Endoscopic Vestibular Approach Thyroidectomy on Pathologic Assessment.

CONTEXT.­: Since 2016, transoral endoscopic thyroid resection with vestibular approach (TOETVA) has been increasingly performed in the United States. Although guidelines for the procedure are evolving, indeterminate and malignant preoperative cytopathologic diagnoses are not a contraindication. There are limited data related to the pathologic examination of these specimens. OBJECTIVE.­: To examine the clinicopathologic features of TOETVA specimens with particular attention to limitations of interpretation of pathologic parameters and final diagnosis. DESIGN.­: We reviewed age, sex, preoperative imaging and cytologic diagnoses, surgical pathology, and clinical follow-up data in TOETVA resections from our institution for procedures performed between March 2016 and December 2019. RESULTS.­: Fifty cases of TOETVA were identified, comprising 48 women and 2 men with a mean age of 47 years. Preoperative cytologic diagnoses were available in 47 cases and included 19 nondiagnostic/benign (Bethesda I/II), 24 follicular lesion of undetermined significance/suspicious for follicular neoplasm (Bethesda III/IV), and 4 suspicious/malignant diagnoses (Bethesda V/VI). Thirty-four cases (68%) among the surgical resection specimens showed disruption and/or fragmentation. Thirty-nine cases were negative for carcinoma, including hyperplasias and benign/indolent neoplasms. Eleven cases exhibited papillary thyroid carcinoma. Final diagnoses were reached in all disrupted/fragmented cases. In 2 cases of papillary thyroid carcinoma, tumor size, microscopic extrathyroidal extension, and margin status could not be determined. CONCLUSIONS.­: A significant proportion of TOETVA specimens are disrupted/fragmented, which can compromise information about tumors, including size, number, margin status, and microscopic extrathyroidal extension. Given that these parameters inform treatment and follow-up, this should be considered when selecting patients for TOETVA.

Performing Calcitonin Immunocytochemistry on an Additional ThinPrep Slide in Fine-Needle Aspiration Diagnosis of Medullary Thyroid Carcinoma.

OBJECTIVES: This study reviewed the institutional experience of performing calcitonin immunostain on an additional ThinPrep slide in fine-needle aspiration (FNA) diagnosis of medullary thyroid carcinoma (MTC). METHODS: Thyroid FNA cases with MTC suspected or included in the differential diagnosis during cytologic evaluation and calcitonin immunostain performed were retrieved and reviewed. RESULTS: Calcitonin immunostain was performed in 132 cases with 41 positive, 81 negative, and 10 indeterminate results. All calcitonin-positive cases had a cytologic diagnosis of MTC while all calcitonin-negative cases were cytologically classified as non-MTCs except for two cases suspicious for MTC. In 10 cases with an indeterminate calcitonin result, diagnoses of non-MTC and suspicious for MTC were rendered in 6 and 4 cases, respectively. Histopathologic follow-up was available in 85 (64%) cases. All cytologically diagnosed MTC cases were confirmed on histopathology. In 3 MTC cases with an indeterminate calcitonin result, 1 case was misclassified cytologically as follicular neoplasm. The calculated sensitivity, specificity, positive predictive value, and negative predictive value of calcitonin immunostain were all 100% for diagnosing MTC. CONCLUSIONS: Our study demonstrates the feasibility of performing calcitonin immunostain on an additional ThinPrep slide. Calcitonin immunocytochemistry is a valuable adjunct test for FNA diagnosis and differential diagnosis of MTC.

Anaplastic Thyroid Carcinoma: Cytomorphologic Features on Fine-Needle Aspiration and Associated Diagnostic Challenges.

OBJECTIVES: Anaplastic thyroid carcinoma (ATC) is an aggressive malignancy, and early diagnosis, often aided by fine-needle aspiration (FNA), is key to improving patient prognosis. While the current literature describes some of the cytologic features (CFs) of this entity, a comprehensive examination of the CFs has not yet been performed. METHODS: We retrospectively searched our electronic database for ATC cases with available slides between January 2008 and December 2019. Cases were examined for 22 CFs and compared with a control group of differentiated thyroid carcinoma. RESULTS: A total of 18 ATC cases meeting our inclusion criteria were identified. Most cases showed moderate to high cellularity (83%) and epithelioid cytomorphology (83%). Architecture included either predominantly groups/clusters of tumor cells (56%) or single tumor cells (44%). The other CFs were as follows: nuclear enlargement (100%), nuclear crowding (89%), nuclear membrane irregularities (100%), multinucleated tumor cells (33%), and background acute inflammatory cells (50%). Of the CFs examined, statistically significant differences between ATC and the control groups were found in the following: nuclear pleomorphism, coarse/clumped chromatin, macronucleoli, apoptosis, and necrosis. CONCLUSIONS: Identification of key CFs in FNA coupled with the clinical history aids in the diagnosis of ATC and helps distinguish it from other mimickers.

Spatially resolved analysis of the T cell immune contexture in lung cancer-associated brain metastases.

Despite unique genetic alterations within brain metastases (BrMs) and an immunologically distinct surrounding microenvironment, the composition and functional properties of tumor-infiltrating lymphocytes within BrM remain largely unexplored. In particular, the expression of coinhibitory receptors, such as programmed cell death 1 (PD-1), T cell immunoglobulin mucin receptor 3 (TIM-3), and lymphocyte activation gene 3 (LAG-3), within BrMs is unknown. Using multiplexed quantitative immunofluorescence (QIF), this study evaluates the localized expression of PD-L1, level and functional profile of major T cell subsets, and coinhibitory receptors within lung cancer-associated BrMs and primary lung tumors. Clinicopathologically annotated samples from 95 patients with lung cancer between 2002 and 2015 were represented in a tissue microarray format. Spatially resolved and multiplexed QIF was used to evaluate PD-L1 protein, phenotype markers for major T cell subsets (CD3, CD4, CD8, and FOXP3), cell-localized activation and proliferation markers (granzyme B and Ki67), and coinhibitory receptors (PD-1, LAG-3, and TIM-3). The signal for each marker was measured in marker-selected tissue compartments, and associations between marker levels, tumor location, and major clinicopathological variables were studied. In total, 41 primary lung tumors and 65 BrMs were analyzed, including paired samples from 11 patients. Levels of tumor PD-L1 expression were comparable between BrMs and primary lung tumors. BrMs had significantly lower levels of all T cell subsets relative to primary lung tumors, and T cells in BrMs displayed lower levels of granzyme B than primary lesions. PD-1, TIM-3, and LAG-3 levels in CD3+ T-cells were also significantly lower in BrMs. Marker expression in patients with paired samples from BrMs and primary lung tumors showed comparable results. High CD3+ T-cells, as well as high levels of TIM-3 and LAG-3 in CD3+ T-cells, were associated with longer overall survival in BrMs but not primary lung tumors. Lung cancer-associated BrMs display lower T cell infiltration, markers of cytolytic function, and immune regulatory signals than primary lung tumors. Despite these differences, high TIM-3 and high LAG-3 expressions in CD3+ T-cells were associated with longer survival. These features are accompanied by comparable levels of PD-L1 protein expression compared with primary lung tumors. These results highlight unique aspects of the tumor immune microenvironment within the brain and provide further support for intracranially focused therapies.

Adverse Histopathologic Characteristics in Small Papillary Renal Cell Carcinomas Have Minimal Impact on Prognosis.

OBJECTIVES: Tumor size has long been used in the management decision-making of patients with renal masses. Active surveillance had recently gained traction in selected patients with tumor size of 4 cm or less. Adverse histopathologic characteristics in papillary renal cell carcinoma (PRCC) have been shown to correlate with worse prognosis. We aimed to study whether such features in small PRCCs provide additional prognostic information. METHODS: Nephrectomies from our institution were collected and reviewed to evaluate for adverse histopathologic features. Clinical follow-up information was collected for all cases. Relationships between the variables were examined by Wilcoxon test and logistic regression. RESULTS: We identified 291 consecutive cases of PRCC. Adverse tumor histopathologic characteristics were significantly related to size. In PRCCs with size greater than 4 cm, there were more cases with high World Health Organization/International Society of Urological Pathology grade and necrosis. Adverse histologic features are less commonly seen in small PRCC and are not associated with lower disease-free survival or disease-specific survival. CONCLUSIONS: Identification of these features in small PRCCs (≤4 cm) through needle core biopsy examination would not provide additional prognostic information in patients for whom active surveillance is considered. Clinical and radiologic follow-up in patients with small renal masses that have a known histologic diagnosis of PRCC should be sufficient.

Prolonged Complete Response of Early Stage Primary Adenocarcinoma of the Lung to Nivolumab Monotherapy.

Immune checkpoint inhibitors are currently employed for the treatment of various malignancies, including advanced melanoma and non-small cell lung cancer. As more patients are treated with checkpoint inhibitors, situations will arise in which early-stage disease may be subjected, intentionally or unintentionally, to these agents. This is especially relevant for patients presenting with multiple primary malignant tumors (MPMTs). Here we report the case of a patient presenting synchronously with metastatic melanoma to multiple regional lymph nodes and stage I lung adenocarcinoma with high Programmed-Death Ligand 1 (PD-L1) expression. Given the high-risk nature of his melanoma, he was treated with nivolumab monotherapy, and had a durable response of both malignancies to a PD-1 inhibitor. He remains disease-free, off therapy sixteen months after completing a 19-month course of treatment. This highlights the complexity of treating patients with MPMTs in the era of effective immunotherapy and raises the possibility of treating primary lung cancer with systemic immunotherapy in situations in which surgery is not feasible due to comorbidities or other circumstances.