Cytologic features of parathyroid fine‐needle aspiration on ThinPrep preparations

Abstract

BACKGROUND: Previous studies have provided cytologic criteria that aid in the recognition of parathyroid tissue on aspirate smears, including high cellularity, the presence of naked nuclei, loose 2-dimensional clusters, and papillary architecture. However, to the authors knowledge, the cytomorphologic features of parathyroid fine-needle aspiration (FNA) on liquid-based preparations have not been previously described. METHODS: The authors retrospectively reviewed all parathyroid FNAs that had aspirate smears and a ThinPrep preparation performed over 10 years at 1 institution. The FNA smears and ThinPrep preparations from each case were deidentified and independently reviewed for cellularity, naked nuclei, architecture, and colloid-like material. RESULTS: Forty patients were included in the current study. When individual cases were compared, the ThinPrep preparation was more likely to have lower cellularity, lack papillary architecture, lack

Fine-Needle Aspiration Cytology of Parathyroid Lesions

“…Some studies suggest subtle differences between parathyroid carcinoma and benign lesions; however, most studies found that in most occasions this distinction is not possible. 9 Tseleni-Balafouta et al 11,12 noted that intranuclear cytoplasmic inclusions were present only in carcinomas; on the contrary, other investigators 11,12 reported intranuclear inclusions in parathyroid adenomas. In rare cases, however, there may be marked pleomorphism with bizarre giant cells, necrosis, and abnormal mitoses, in which cases a diagnosis of carcinoma can be suggested.…”

“…Thyroid epithelial cells have also been reported to be present in up to 31% of parathyroid aspirates, and extra caution must be exercised not to confuse these contaminant cells with the lesional cells. 4,7,9 Parathyroid cells, particularly the oncocytic variant of parathyroid adenoma, can have abundant cytoplasm that can easily be confused with Hürthle cell lesions of the thyroid (Figs. 1D, E).…”

“…Liquid-based preparations may show more microfollicular pattern and rarely exhibit papillary architecture. 9 Parathyroid cells are generally round to oval with scant cytoplasm that may occasionally contain vacuoles. The nuclear size is small, comparable to that of a red blood cell.…”

“…They may rarely have conspicuous nucleoli, but mitotic rate is generally insignificant. 7,9,10 The distinction between the different parathyroid lesions cannot be made reliably on cytology. Some authors suggest that parathyroid hyperplasia has more tightly cohesive cell clusters with monomorphism, whereas parathyroid adenoma features more dispersed or loosely cohesive cells with pleomorphism and anisokaryosis.…”

“…This has been echoed by many studies that found colloidlike material in up to 24% of parathyroid aspirates. 7,[9][10][11] Ancillary Tests Immunohistochemistry can be extremely helpful in the distinction of cells of parathyroid origin, particularly from thyroid follicular cells. If there is sufficient material, cell block sections generally offer better results, although some investigators reported comparable results with destained Papanicolaou-stained smears.…”