ABSTRACT
BACKGROUND: Morphologic and genetic analysis of thyroid nodules may be performed from a single vial. Preanalytic variables that affect nucleic acid extracted from a single vial are evaluated. METHODS: Thyroid fine-needle aspiration (FNA) specimens collected in CytoLyt were evaluated. A ThinPrep slide was prepared. Extracted nucleic acids were analyzed using Oncomine Comprehensive Panel, version 2, after Ion AmpliSeq library preparation. A pathologist and a cytotechnologist enumerated specimen cellularity. RESULTS: Fifty-six samples were collected from 55 nodules in 53 patients. Bethesda category correlated with cellularity (P = .01), and storage time (median, 43 days; range, 7-77 days) was longer for specimens in categories II and III than for those in categories IV and VI (P = .01). The mean specimen DNA concentration was 4.5 ng/µL (range, 0-23.8 ng/µL), and 25 (45%) had concentrations >3.3 ng/µL. The mean specimen RNA concentration was 4.8 ng/µL (range, 0-42.4 ng/µL), and 31 (55%) had concentrations >1.4 ng/µL. Nucleic acid quantity increased with epithelial cellularity. Storage time weakly correlated with the quantity of extracted DNA, independent of cellularity, but not extracted RNA. Greater proportions of cell-free DNA and lesser proportions of long, intact RNA fragments were extracted from a subset of samples with longer storage time. Among 15 single nucleotide variants, the median mutant allelic fraction was 15.1%. One false-negative result was identified. Five specimens subsequently determined to harbor a genetic alteration failed quality metrics. CONCLUSIONS: Cellularity and storage time affect the quantity and quality of nucleic acid extracted from thyroid FNA specimens collected in CytoLyt. Further investigation will serve to quantify the magnitude of such effects and to elucidate other contributing factors.
Subject(s)
Cytodiagnosis/methods , Genetic Testing/methods , Nucleic Acids/analysis , Specimen Handling/standards , Thyroid Gland/pathology , Thyroid Neoplasms/pathology , Thyroid Nodule/pathology , Adult , Aged , Aged, 80 and over , Biopsy, Fine-Needle , Female , Follow-Up Studies , Humans , Male , Middle Aged , Mutation , Nucleic Acids/genetics , Prognosis , Retrospective Studies , Thyroid Gland/metabolism , Thyroid Neoplasms/genetics , Thyroid Nodule/genetics , Young AdultABSTRACT
BACKGROUND: Fine needle aspiration (FNA) of breast masses in pregnant or lactating women is an uncommon procedure, and cytological interpretation is considered problematic due to atypia inherent to secretory change in glandular epithelia. Previous descriptions of "lactating adenoma" (LAd), the most common tumor in this population, have been on direct smears (DS), while ThinPrep (TP, Hologic, Boxborough, MA) findings therein remain largely uncharacterized. METHODS: FNA cases from breast masses in pregnant or lactating women (2005-2012), processed as TP and/or DS were retrospectively reviewed. RESULTS: 28 cases from as many patients (mean age 36 years), at 23 weeks of pregnancy to 10 months postpartum, were reviewed. Size of mass ranged from 1.0 to 4.5 cm. Corresponding histopathology was available in 21/28 cases. TP was available in 24/28 cases. Relative to DS, in TP, LAd showed "lacy" fragments, tissue paper-like texture, and globular clumps of "milky" background material, with embedded singly dispersed "bare" epithelial cell nuclei containing cherry-red macronucleoli. Architecture appeared disrupted in TP with isolated cells, smaller cell clusters, and lobules in LAd. Cellular morphology was better preserved in TP. Cytological features of carcinoma on TP were similar to DS. There were no false-positive cases. In this series, LAd was the most common diagnosis for breast masses in pregnant and lactating women (78.5%) and demonstrated background, architectural, and cellular alterations on TP. CONCLUSION: In this setting, malignancy is an important consideration (encountered in 3/28, 11% of cases, including one false-negative angiosarcoma case).
