OBJECTIVE: To determine the advantage of examining fine needle aspiration (FNA) smears of papillary thyroid carcinoma (PTC) under a 100 × oil-immersion objective, which is capable of optically sectioning the cells. STUDY DESIGN: Two hundred neoplastic cells were counted under a high-power (40×) objective as well as oil-immersion (100×) objective in 54 PTC cases classified into variants: 14 follicular neoplasms, 8 Hürthle cell neoplasms, 5 medullary thyroid carcinomas and 9 hyperplastic lesions. The counts of cells with 2 important diagnostic features of PTC, intranuclear cytoplasmic inclusions (INCIs) and grooved nuclei, were compared between various groups and between high-power and oil-immersion objectives in each group. RESULTS: Cytomorphologic features, such as INCI and nuclear grooves, were visible usually under 2 or 3 focal planes under the oil-immersion objective as opposed to a single plane under the high-power objective. In PTC cases, the mean cell count, 10.1 (±1.75 SE) with INCIs, under the oil-immersion objective was significantly higher than the count, 6.1 (±1.32 SE), under the high-power objective (p = 0.023). INCIs were not observed under the high-power objectives in 11 (20.4%) PTC cases, but in 5 (45.5%) of these they were visible under the oil-immersion objective. In PTC the mean cell count, 88.0 (±4.96 SE), with grooved nuclei under the oil-immersion objective was also significantly higher than the count, 69.5 (±4.87 SE), under the high-power objective (p = 0.010). Under the high-power objective, <20.0% of cells with grooved nuclei were observed in 12 (22.2%) cases of PTC. However, examination under the oil-immersion objective revealed ≥20.0% cells with grooved nuclei in 9 (75%) of these. In PTC the mean cell counts with INCIs as well as grooved nuclei under the oil-immersion objective were significantly higher than those of follicular neoplasms, Hürthle cell neoplasms, medullary carcinoma and hyperplastic lesions. CONCLUSION: In PTC, examination of FNA smears for INCIs and grooved nuclei under an oil-immersion objective was diagnostically more useful as compared to a high-power objective.
|Number of pages||12|
|Journal||Analytical and Quantitative Cytology and Histology|
|Publication status||Published - 1 Apr 2005|
- Cytoplasmic inclusions; intranuclear inclusions; aspiration biopsy
- Fine-needle; nuclear grooves