Fate of nondiagnostic thyroid fine needle aspirations.

BACKGROUND: Thyroid nodules may be detected during the workup of thyroid hormone abnormalities and as incidental findings during unrelated imaging studies. The diagnosis of a thyroid nodule is mainly established by performing fine needle aspiration (FNA) under ultrasound guidance. Thyroid nodules are classified as nondiagnostic, defined in the Bethesda System for Reporting Thyroid Cytopathology as samples with excess blood, cyst fluid only, and lack of thyroid follicular cells. The current study evaluates a series of nondiagnostic FNAs to assess whether repeat sampling improves yield and what patient management, and outcomes are after a nondiagnostic FNA. METHODS: Thyroid FNAs from 2016 to 2023 were retrieved from our institution archives. All cases were performed under ultrasound guidance and with rapid on-site evaluation. Cases were assigned the Bethesda System Category. Nondiagnostic FNAs were further reviewed for repeat FNA procedures, potential molecular testing, or diagnostic resections. RESULTS: In total 3104 thyroid FNAs were reviewed, with 153 (4.9%) being nondiagnostic. Of the 154 FNAs, there were 129 patients with an average age of 60 and a male-to-female ratio of 1:3.2. Of the 130 patients, there were 50 patients who underwent 55 repeat FNAs. Thirty-seven (67%) of the repeats were benign, 13 (24%) were nondiagnostic again, and 5 (9%) were atypia of undetermined significance (AUS). Molecular testing was performed on repeat FNAs diagnosed AUS. Four cases showed no mutations and had a high likelihood of being benign. One case did have an NRAS Q61R mutation, and resection revealed a noninvasive follicular thyroid neoplasm with papillary-like nuclear features. Seventeen (13% of all cases) with nondiagnostic FNA were resected. Twelve (71%) thyroidectomies showed benign adenomatous nodules. The remainder showed incidental papillary thyroid microcarcinoma (0.1 cm), an infarcted follicular adenoma, a noninvasive follicular thyroid neoplasm with papillary-like nuclear features, and metastatic renal cell carcinoma (2×). CONCLUSION: Thyroid nodules with nondiagnostic cytology are reassuring of being highly likely a benign nodule. Only 5 of the 55 (9%) repeat FNAs yielded abnormalities, with only one of those being truly a follicular neoplasm (confirmed by molecular testing and resection). No primary thyroid malignancies have been identified in follow-up (repeat FNA or surgery). Clinical and ultrasound follow-up may be more appropriate management for nondiagnostic thyroid FNAs.

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 844 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 65.7 years (range 48-79); 9 males and 5 females. All were smokers with an average pack-year of 40.7 (range 10-70). Ten had metastases, mostly in the brain (n = 4) and pleura (n = 4). After a follow-up period of up to 102 months, 9 died, 3 were alive free of disease, 1 was alive with disease, and 1 was lost to follow-up. The median survival was 12.2 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 5 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 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.

Parakeratotic-like cells in effusions - A clue to diagnosis of malignant mesothelioma.

BACKGROUND: Malignant mesothelioma (MM) is an aggressive neoplasm with a poor prognosis. Its incidence has been increasing worldwide. Cytological examination of an effusion is often the first opportunity to diagnose MM. However, the cytological diagnosis of MM can be difficult. We have noticed that parakeratotic-like cells, with orange cytoplasm and pyknotic nuclei, are present in many cases of mesothelioma on Papanicolaou-stained cytology slides. Although this cytological finding has been described previously, to our knowledge, there has been no systematic study of this finding. Our study is to determine whether the presence of small parakeratotic / orangeophilic cells (PK-like cells) is specific for the cytodiagnosis of mesothelioma. MATERIALS AND METHODS: A total of 90 body fluid cases were selected from our archived specimens in the Cytology Section at the University of Chicago Hospital accessioned between January 2000 to November 2011. They included 30 cases of mesothelioma, 30 cases of adenocarcinoma, and 30 cases of reactive mesothelial cells. RESULTS: PK-like cells were present in 83% of the mesothelioma cases, 13% of the adenocarcinoma cases, and 7% of the reactive cases. Our data showed that the presence of PK-like cells has a specificity of 90%, sensitivity of 83%, positive predictive value of 81%, and negative predictive value of 84% for the diagnosis of malignant mesothelioma in body cavity fluids. CONCLUSION: The presence of PK-like cells in the effusion specimen, especially in pleural effusions, is a highly specific and moderately sensitive cytological feature for diagnosis of mesothelioma.

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.

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.

Accuracy of Subclassification and Grading of Renal Tumors on Fine Needle Aspiration Cytology Alone.

BACKGROUND: Fine needle aspiration (FNA) of renal masses can distinguish between benign and malignant neoplasms in 73-94% of cases. Previous studies suggested the correct subclassification of renal cell carcinomas (RCCs) by cytomorphology can be achieved in up to 80% of cases. However, as RCCs become increasingly subclassified by molecular signatures, correct subclassification based on cytology alone is increasingly difficult. DESIGN: Two FNA passes (2 stained with Diff-Quik® and 2 with the Papanicolaou method) were performed on all fresh nephrectomy specimens for a 1-year period. There were 30 cases in this study, with 29 primary renal tumors and 1 case of metastatic lung adenocarcinoma. Each case was assigned a random number and came with 2 slides (1 from each staining method). Eight cytopathologists were asked to provide a diagnosis and the World Health Organization/International Society of Urological Pathology (WHO/ISUP) grading if applicable. Fleiss' Kappa and Cohen's Kappa equations were used to look at inter-rater variability. RESULTS: When compared to the surgical pathology diagnosis, the average percent correct diagnosis for all cytopathologist was 35%. Chromophobe RCCs had the best average percent accuracy at 72% followed by clearcell RCC at 48%. Average accuracy for grading RCCs was 40%. Inter-rater variability among the cytopathologists for all RCC diagnoses was fair with a Fleiss' Kappa coefficient of 0.28. For the WHO/ISUP grade, the weighted coefficient for each pathologist ranged from 0.11 to 0.45, ranging from fair to moderate, respectively. CONCLUSIONS: Renal tumors are difficult to classify on cytopathology alone. Core needle biopsy and ancillary studies are necessary if diagnosis will change management.

Correlation of cytopathology with flow cytometry and histopathology for the diagnosis of hematologic malignancies in young adults presenting with cervical lymphadenopathy.

BACKGROUND: Fine-needle aspiration (FNA) is frequently utilized in the diagnostic workup of lymphadenopathy. We evaluated the correlation of cytopathology with flow cytometry and tissue biopsy results and assessed the prevalence of specific malignancies in young adults presenting with cervical lymphadenopathy. METHODS: Database was searched for cervical lymph node FNA performed by a cytopathologist in patients aged 18-30 years from 2005 to 2017. RESULTS: Cervical lymph node FNA was performed on 48 patients without prior history of malignancy. Nineteen patients had cytology results only, of which all were interpreted as benign reactive lymph node. None developed subsequent malignancies. The remaining 29 patients had cytology with flow cytometry and/or tissue biopsy results. A benign reactive cytology diagnosis was rendered in 18 (62%) cases, of which 11 had concordant diagnosis on flow cytometry, 2 had tissue biopsy, and 3 had both. Eleven (38%) patients had cytology results concerning for a hematologic malignancy, of which 7 were confirmed by flow cytometry and 3 by both flow cytometry and tissue biopsy. Cervical lymph node FNA has 94.1% sensitivity, 83.3% specificity, 88.9% positive predictive value, and 90.9% negative predictive value. The most common hematologic malignancy in our young adult population presenting with cervical lymphadenopathy was Hodgkin lymphoma. CONCLUSION: FNA is a useful first-line diagnostic procedure for assessing cervical lymphadenopathy in young adults to allow for better triage of specimens for flow cytometry and/or tissue biopsy concerning for a hematologic malignancy and potentially avoid invasive excisional biopsy in a proportion of cases.

Clinical case seminar: Riedel's thyroiditis: report of a case complicated by spontaneous hypoparathyroidism, recurrent laryngeal nerve injury, and Horner's syndrome.

A 42-yr-old woman presented with hyperthyroidism and a large, firm, irregular goiter. Within a few weeks she became hypothyroid. Five months later she developed increasingly severe neck pain and compressive symptoms. The goiter had become rock hard. A fine needle aspiration biopsy showed features of chronic thyroiditis and fibrosis. She partially responded to a course of glucocorticoids. Tamoxifen was added, with marked improvement in goiter size and pain. Both medications were tapered off. Two months later the patient experienced paresthesias of the fingertips, perioral numbness, and a seizure. She was found to have spontaneous primary hypoparathyroidism. Three months later the patient became hoarse and experienced difficulty in breathing. She was found to have a massively enlarged thyroid with compression of the right internal jugular vein and encasement of the right carotid artery as well as tracheal narrowing. She also had right vocal cord paralysis due to recurrent laryngeal nerve involvement. Because of airway compromise, an emergency isthmusectomy was performed, and the patient was given a postoperative course of glucocorticoids with gradual improvement. Postoperative diagnosis was Riedel's thyroiditis. Two months later she presented with near-syncope and was found to have bradycardia, hypotension, and right Horner's syndrome, presumably due to compression of the right carotid sheath. She was given i.v. glucocorticoids and tamoxifen. Six months later and 18 months after her initial presentation, the patient is doing remarkably well. Her goiter has regressed by more than 50%, and she no longer has any pain or difficulty breathing. She remains a little hoarse and has persistent hypothyroidism and hypoparathyroidism. She is taking prednisone (5 mg, this is being tapered very slowly) and tamoxifen (20 mg) daily. This case illustrates the protean manifestations of Riedel's thyroiditis, a rare but fascinating disease. The epidemiology of this disease, its pathophysiology and complications, and the roles of surgery and medical therapy are reviewed.

Amyloid tumor: a clinical and cytomorphologic study.

We describe the cytologic findings and clinical presentation of three unusual cases of amyloid tumor. Two of our patients had low-grade lymphoid malignancies and the third insulin-dependent diabetes mellitus. In no cases was amyloid suspected as the cause of mass lesion. Two of our cases presented with superficial soft tissue mass and the third with right breast masses and bilateral axillary lymph node enlargement. Air-dried slides from all aspirated cases were stained with Diff-Quik for specimen adequacy evaluation. The remaining fixed slides were stained with Papanicolaou stain. Amyloid appeared as dark-blue to purple clumps of acellular material on Diff-Quik stain, accompanied with chronic inflammatory cell infiltrates and multinucleated giant cells, simulating granulomatous inflammation. Papanicolaou stain demonstrated cyanophilic to orangophilic acellular material. Amyloid was suspected and subsequently confirmed by Congo red stain.

Immunohistochemical analysis of E-cadherin and zeste homolog 2 expression in endoscopic ultrasound-guided fine-needle aspiration of pancreatic adenocarcinoma.

BACKGROUND: Recent studies have demonstrated that partial or complete loss of E-cadherin (EC) and nuclear accumulation of zeste homolog 2 (EZH2) are hallmarks of poorly differentiated pancreatic adenocarcinoma (PAC). Depletion of EZH2 sensitizes cancer cells to chemotherapy in vitro. The objective of this study was to determine EC and EZH2 expression by immunohistochemistry (IHC) in samples obtained by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) as potential biomarkers for treatment and disease prognosis. METHODS: Thirty-eight EUS-FNA samples from patients with a PAC diagnosis were analyzed by IHC for EC and EZH2 expression. Seven corresponding surgical resection specimens were included in the study. The intensity of EZH2 and EC expression in PAC and in normal gastrointestinal pick-ups (internal positive control) was scored by using a 4-tier grading system. RESULTS: EC demonstrated a focal, weak-to-moderate decrease in 24 PAC samples. Complete loss of EC expression was observed in the poorly differentiated areas represented by single tumor cells. The average staining intensity of EC in samples of poorly differentiated PAC was significantly lower than that of moderately differentiated PAC samples (P = .0005). EZH2 was variably positive in 31 of 38 PAC samples. The average staining intensity of EZH2 in moderately and poorly differentiated PACs did not differ significantly (P = .81). CONCLUSIONS: EC and EZH2 expression was determined reliably by IHC on paraffin sections of EUS-FNA cell block specimens. The current results were consistent with prior reports indicating a decrease or loss of EC expression in poorly differentiated PAC. However, EZH2 expression did not always correlate inversely with EC expression and was more heterogeneous.

Follicular lesions of the thyroid: a retrospective study of 1,348 fine needle aspiration biopsies.

Fine needle aspiration (FNA) has proven to be an effective tool in management of patients with thyroid nodules. However, the diagnosis of follicular patterned lesions can be challenging. The surgical and cytopathology computer database at a large referral medical center was searched for cases that had both cytologic and histologic thyroid accessions from January 2004 to November 2008. A total of 1,255 histologic thyroid specimens and 2,776 thyroid FNA biopsies were retrieved for review. Histologically, 272 overt malignancies were identified; 20 (7.4%) were follicular carcinomas. Cytologically, 1,348 cases were follicular-patterned lesions, comprising 1,044 cases of "benign follicular nodules" (BFN), 137 cases of "follicular lesions of undetermined significance" (FLUS), and 167 cases of "suspicious for follicular neoplasm" (SFN). Seventy-nine (7.5%) of BFN, 23 (16.8%) of FLUS, and 65 (38.9%) of SFN cases had histologic follow-up. Overt malignancy, a cystic papillary carcinoma, was identified histologically in only one case of BFN, for a negative predictive value of 98.7%. Overt malignancy was identified histologically in two cases of FLUS, both follicular variant of papillary carcinoma, for a positive predictive value of 8.7%. Overt malignancy was identified histologically in 14 cases of SFN, for a positive predictive value of 21.5%. Five follicular carcinomas were identified histologically in the SFN category, all minimally invasive. Incidental ("occult") papillary microcarcinoma were identified histologically in all three categories. In this study, the risk of overt malignancy increases from 1.3%, to 8.7%, to 21.5% for BFN, FLUS, and SFN, respectively. All follicular carcinomas identified histologically occurred in the SFN category and all were minimally invasive. Papillary microcarcinomas can occur in any of the three diagnostic categories.