2017 Sec 1 Green Book

Huyett et al

general anesthesia and the influence of FNAB on surgical decision making. Methods Institutional review board approval was obtained from the University of Pittsburgh. Patients aged 0 to 21 years were retrospectively identified in a cytopathology database for having undergone FNAB of a HNM. Consecutive subjects from July 2007 to July 2014 were included, and there were no exclusion criteria. All patients were seen in the pediatric otolaryngology or endocrinology departments where the need for FNAB was determined and consent was obtained for the procedure. The decision to proceed with nonthyroid FNAB was typically based on persistence of a neck mass beyond 4 weeks despite treatment with antibiotics. Cases atypical for benign lymphadenopathy were referred for FNAB sooner (eg, unusual location, rapid enlargement, weight loss, night sweats, skin changes, fixed/immobile mass). All nonthyr- oid FNABs were performed because the patient was con- sidered a potential surgical candidate, the mass was atypical, and/or the family or medical team desired a pathologic diagnosis. Given the high rate of malignancy in pediatric thyroid nodules, patients with lesions greater than 1 cm or smaller with concerning ultrasonographic features (hypoechogenicity, irregular margins, or increased vascu- larity) were offered FNAB. Fine-needle aspiration biopsies were subsequently per- formed in the otolaryngology clinic or inpatient ward by the cytopathologist, the interventional radiology suite (IR) by a radiologist, or the operating room (OR) by the surgeon or cytopathologist. Topical (4% lidocaine cream), general, or topical plus sedative anesthesia was used. As a standard practice at our institution, all biopsies performed in the IR suite used image guidance, and all others were performed by palpation. Most thyroid nodules were biopsied with ultra- sound guidance, consistent with current recommendations. 6 A 25- to 27-gauge needle was used, and approximately 3 to 5 passes were performed for each targeted site, represent- ing a single FNAB. Patients with multiple FNABs therefore had more than 1 targeted HNM, multiple encounters, or both. Aspirated material was used for smear preparation, including air-dried slides stained with Diff-Quik and alcohol-fixed slides stained with the Papanicolaou stain. Residual material was submitted for ThinPrep (Hologic Inc, Marlborough, Massachusetts) processing, microbial cultures, molecular studies, flow cytometry, and/or cell block pre- paration, depending on the immediate interpretation. Cell block sections were stained with hematoxylin and eosin stain, and additional levels were used for immunostains, special stains, or other ancillary testing. The FNABs were interpreted by 1 of 9 cytopathologists, although most (88%) were interpreted by 1 of 2 cytopathologists with pediatric expertise. Nonthyroid cases received diagnoses with an ade- quacy interpretation (unsatisfactory, less than optimal, or satisfactory), a primary interpretation (nondiagnostic, nega- tive for malignant cells, atypical cells present, suspicious

for malignant cells, or positive for malignant cells), and a free text explanatory diagnosis. Thyroid cases received an adequacy interpretation, a primary interpretation using The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC), 4 and a free text explanatory diagnosis. The determination of a nonsurgical (negative) vs surgical (positive) FNAB result was made for each patient. Final out- comes were then established either through correlation to sur- gical histopathology or clinical follow-up. Histopathology based on surgical biopsy (incisional or excisional) is consid- ered the reference standard in the diagnosis of an HNM. Clinical follow-up is included as a secondary reference given that most pediatric HNMs are benign and do not undergo sur- gery and therefore histopathologic evaluation. True positives were cytopathologic results that warranted surgical treatment and were confirmed as such histopatholo- gically. True negatives were cytopathologic results that did not indicate a need for surgery and were confirmed histo- pathologically as such. Clinical true negatives were cyto- pathologically negative conditions that resolved or did not progress without surgical intervention. False positives were cytopathologic results that indicated a need for surgical treatment but histopathology demonstrated a nonsurgical condition. False negatives were cytopathologic results that did not indicate a need for surgery but were histopathologi- cally proven to be conditions where surgery was indicated. Pathologists interpreting surgical histopathology were dis- tinct from our cytopathologists and neither was blinded to clinical information or pathology results. Certain conditions, such as atypical mycobacterial infec- tion, cervicofacial abscess, lymphovenous malformations, and lymphoma, may warrant surgical diagnosis or treatment but may also appropriately proceed directly to medically therapy. These cases were all considered positive on the basis that surgery could be indicated. If surgery was pursued and histopathology confirmed the cytopathologic result, the case was a true positive. If the appropriate medical therapy was initiated and was effective, the result was a clinical true positive. Individual diagnoses and demographic data such as age at first encounter and sex are presented on a patient level. Features unique to each encounter such as complications, FNAB venue, and level of anesthesia are presented on an encounter level. Specificity, sensitivity, and nondiagnostic results are presented on an FNAB level. SPSS version 21 (SPSS, Inc, an IBM Company, Chicago, Illinois) was used to analyze the data. Sensitivity, specifi- city, and positive and negative predictive values were calcu- lated using the definitions as detailed above. Nondiagnostic results were not included in these statistics, and no missing data were encountered. A P value \ .05 was considered sig- nificant. Age at first encounter was compared between the high and low level of anesthesia and thyroid/nonthyroid groups using an independent sample t test. Age was com- pared between the thyroid/nonthyroid groups using Pearson’s x 2 test. Generalized estimating equations were used to compare the number of nondiagnostic results

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