Faculty Bibliography

Introduction: Thyroid fine-needle aspiration (FNA) cytology combined with molecular testing guides individualized patient management by providing information regarding tumor biology and the risk of recurrence associated with specific mutations in the indeterminate groups (Bethesda group III-V). Thyroid adenomaassociated (THADA)-IGF2BP3 fusions have been identified as an oncogenic event in thyroid neoplasms, but the clinical-pathologic features and subsequent management are not well-established. Here we report the findings associated with thyroid nodules with THADA-IGFBP3 fusions in our institution.
Material(s) and Method(s): FNA cytology samples of thyroid nodules during 01/2015-12/2016 with the diagnosis of atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS; Bethesda III), follicular neoplasm/ suspicious for follicular neoplasm (FN/SFN; Bethesda IV) and suspicious for malignancy (Bethesda V) with corresponding ThyroSeqV2 data were assessed. Molecular test results yielding a THADA gene fusion were identified. In addition, follow-up surgical pathology and available radiology results were reviewed.
Result(s): 186 out of 558 (33.3%) thyroid nodules displayed molecular alterations; 7 out of 186 (3.8%) Bethesda category III-V nodules with ThyroSeq molecular alterations displayed isolated THADA-IGFBP2 fusions (Table 1). The median age was 45 years. The female to male ratio was 5:2. The nodule sizes ranged from 1.8 to 5.0 cm. Four (57%) patients had surgery; three cases displayed noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) on histology; one case was a follicular adenoma. No patients had recurrence or metastasis on follow-up.
Conclusion(s): Our pilot study shows that thyroid nodules with THADA-IGF2BP3 fusions display low-risk/indolent features. These findings may aid in clinical management decisions in patients presenting with thyroid nodules with isolated THADAIGF2BP3 fusions on molecular testing

OBJECTIVES/OBJECTIVE:Our study assesses whether the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) offers any benefit over the original cytology classification, and measures interobserver agreement. METHODS:Four cytopathologists retrospectively blindly classified preoperative cytology by MSRSGC from 101 resected salivary tumors. Consensus MSRSGC diagnoses were correlated with surgical pathology diagnoses and compared with the original cytology classification. Diagnostic parameters were calculated for both systems. Interobserver variability was assessed. RESULTS:The original cytology classification vs MSRSGC had sensitivity, specificity, positive predictive value, and negative predictive value of 75.0% vs 78.3%, 97.1% vs 98.0%, 91.2% vs 94.7%, and 90.1% vs 90.0%, respectively. The original cytology classification risk of neoplasm (RON) was 91.7% for "negative for malignancy" and 100.0% for other categories. The MSRSGC RON was 71.4% in category II (nonneoplastic) and 100.0% in all other categories. The original cytology classification risk of malignancy (ROM) ranged from 0.0% for "atypical" to 100.0% for "positive for malignancy." The MSRSGC ROM ranged from 0.0% in categories I (nondiagnostic) and III (nonneoplastic) to 100.0% in category VI (malignant). Weighted agreement using the MSRSGC was 92% (Gwet AC1, 0.84); unweighted agreement was 69% (Gwet AC1, 0.64). MSRSGC category IVA (benign neoplasm) was most likely to show interobserver agreement, with complete agreement in 67% of cases. CONCLUSIONS:The MSRSGC performs similarly to the original cytology classification and shows relatively high interobserver agreement.

OBJECTIVES/OBJECTIVE:Data on Papanicolaou (Pap) tests with atypical glandular cells (AGCs) with concurrent squamous cell abnormalities (AGC + Sq) are limited. We evaluated histologic outcomes and the role of high-risk human papillomavirus (HR-HPV) testing in this setting compared with AGCs without concurrent squamous cell abnormalities (AGC-alone). METHODS:This study used a retrospective cohort of patients with Pap test diagnoses of AGC + Sq and AGC-alone between October 2013 and August 2021. RESULTS:We included 287 Pap tests from 278 patients. The HR-HPV test was positive in 55% of AGC + Sq cases and 14% of AGC-alone cases (P < .0001). Most AGC + Sq cases displayed squamous lesions (41.5%) or were benign (41.5%) on histology, whereas AGC-alone cases were predominantly benign (72%) or extracervical neoplasms (18%). AGC + Sq cases showed higher rates of significant histologic lesions (P = .0001), which were associated with positive HR-HPV status (P = .0012). In AGC-alone cases, HR-HPV status was associated with significant histology only in patients 50 years of age or younger. In both groups, 20% or more of HR-HPV-negative patients harbored significant lesions. CONCLUSIONS:AGC + Sq represents a distinct group of patients. HR-HPV testing and patient age provide useful information in the evaluation of AGC, but triage based on HR-HPV testing is not recommended because of the potential for missing significant lesions.

Myoepithelial carcinoma (MEC) of soft tissue, also known as malignant myoepithelial tumor, is an uncommon malignancy. Cytologic diagnosis of this entity is challenging due to its rarity and heterogeneous morphology. We report a case of MEC in a 22-year-old man, who presented with a 6.5 cm soft tissue mass on his right distal forearm that has been enlarging over the past 3 months. Ultrasound-guided fine-needle aspiration (FNA) revealed abundant isolated neoplastic cells ranging from spindled cells to epithelioid and plasmacytoid morphology in a myxoid background. These cells showed moderate cytologic atypia characterized by high-nuclear/cytoplasmic ratio, irregular nuclear contours, and prominent nucleoli. The cytoplasm varied from dense to vacuolated and occasionally rhabdoid with intracytoplasmic inclusions. Scattered bi- and multinucleated cells were identified. A diagnosis of high-grade malignancy was made with the differential diagnosis including rhabdomyosarcoma and melanoma. A subsequent core biopsy of the tumor showed immunoreactivity for pan-cytokeratins, calponin, p63, and smooth muscle actin. INI-1 was lost. SOX-10 and Melan-A were negative. Molecular studies showed loss of SMARCB1 (INI-1) and CDKN2A. Gene fusion studies did not detect any fusion. A diagnosis of soft tissue MEC was made which is a challenge on FNA due to several cytologic mimickers including rhabdomyosarcoma, epithelioid sarcoma, extrarenal rhabdoid tumor, extra-axial chordoma and melanoma. Recognition of the biphasic cell population in a myxoid background and a battery of immunohistochemical stains are crucial for accurate diagnosis.

INTRODUCTION/BACKGROUND:The American College of Radiology (ACR) Thyroid Imaging Reporting and Data Systems (TI-RADS) was developed to standardize thyroid ultrasound reports and predict the likelihood of malignancy. In our study, we aimed to correlate indeterminate thyroid fine needle aspiration cytology cases with preceding ultrasound (US) ACR TI-RADS scores and concurrent molecular testing results to examine how well the use of the ACR TI-RADS in our institution predicted which patients with indeterminate cytology might harbor molecular alterations. MATERIALS AND METHODS/METHODS:We performed a retrospective review of thyroid nodules. Patients with US reports that included TI-RADS scores, fine needle aspiration specimens with indeterminate cytology (Bethesda class III-V), and molecular testing results were included. RESULTS:A total of 46 indeterminate cytology cases had had preceding US reports with TI-RADS scores and molecular testing (Bethesda class III, n = 37; Bethesda class IV, n = 6; Bethesda class V, n = 3). Most of the indeterminate cases had had a TI-RADS score of TR4 (31 of 46; 67.39%) or TR5 (9 of 46; 19.57%). RAS mutations were the most common alteration (n = 12). Of the 46 cases, 22 (47.85%) showed no alterations. Ten cases proceeded to surgery, of which seven displayed malignancies. CONCLUSIONS:Molecular testing in cytologically indeterminate thyroid nodules provided valuable information for TR4 and TR5 lesions; however, the TR2 and TR3 lesions often had no molecular alterations. These findings highlight the potential value of including US imaging features when assessing the significance of indeterminate cytology findings.

BACKGROUND:Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is responsible for coronavirus disease 2019 (COVID-19), is known to cause severe respiratory infections with occasional accompanying pleural effusion (PE), pericardial effusion (PCE), or peritoneal effusion (PTE). The effect of COVID-19 on effusion cytology is not yet known. This study aimed to examine the cytomorphologic features and workup of effusion fluids in patients with active COVID-19 infection versus those in recovery. METHODS:PE (n = 15), PCE (n = 1), and PTE samples (n = 20) from hospitalized patients with a SARS-CoV-2 infection (from June 1, 2020, to December 30, 2020) were reviewed. Effusion fluids with metastatic carcinoma were excluded. Differential cell counts, cytomorphology, and relevant immunostains for effusion fluids were retrospectively evaluated and compared between patients with active infection (positive on a SARS-CoV-2 nucleic acid amplification test [NAAT] within 2 months; n = 23) and those in the recovery phase from COVID-19 (negative on a SARS-CoV-2 NAAT for >2 months; n = 13). RESULTS:The cytology diagnoses were negative for malignancy (n = 31), atypical (n = 4), and suspicious for malignancy (n = 1). Active infection cases showed more atypical mesothelial cells than recovery cases (P < .05); some had enlarged nuclei, prominent nucleoli, occasional multinucleation, and bizarre nuclei. Immunostains were performed more often in active infection cases than recovery cases (47.8% vs 7.7%; P < .05). Differential cell counts (available for 28 cases) showed no significant differences between the active infection and recovery groups. CONCLUSIONS:This study found atypical and bizarre mesothelial cells more often in effusions of cases with active COVID-19 infection in comparison with patients in recovery. It is important for cytopathologists to become familiar with the cytomorphologic effects of SARS-CoV-2 on effusion cytology so that these cases can be properly triaged.

Background: Bile duct brush cytology (B