Parathyroid lesions: Difficult diagnosis on cytology

Abstract

Cytology of parathyroid lesion (PL) is often confused with that of thyroid lesions. Differentiation between thyroid and PL is very difficult on cytomorphology because of their similar features and close anatomical proximity. Three cases of PLs reported on cytology in last one year were retrieved from archives of cytology department. Their cytomorphological details were studied and were correlated with the available biochemical parameters. Histopathology was available in two cases. Radiological assistance and parathyroid hormone (PTH) assessment in our cases formed the basis of diagnosing PLs on cytology. We discuss the differential diagnosis and pitfalls in cytological diagnosis of PLs. However, histopathology remains the gold standard for diagnosis. Interpretation of PLs on cytology remains problematic due to its rarity and limited available literature. The cytomorphology combined with clinical and biochemical data supported by histopathology are necessary to improve the diagnostic sensitivity of PLs. Diagn. Cytopathol. 2016;44:704-709. © 2016 Wiley Periodicals, Inc.

Distinguishing parathyroid and thyroid lesions on ultrasound‐guided fine‐needle aspiration: A correlation of clinical data, ancillary studies, and molecular analysis

“…Nuclear overlapping and nuclear molding, which are uncommon findings in benign thyroid aspirates, also were reported as findings in parathyroid aspirates . One case series also found similar features . Dimashkieh and Krishnamurthy reported that nuclei measuring smaller than thyroid follicular cells, bare nuclei, stippled chromatin, and a prominent vascular network with adherent cells indicated parathyroid origin .…”

“…Common major cytomorphologic features of parathyroid tissue that have been reported in the literature include a papillary-like pattern with fibrovascular cores or prominent vascular network/proliferation, stippled chromatin, follicular pattern, and bare nuclei (Table 5). 2,[4][5][6][7][8][9][18][19][20][21][22] The majority of these studies also concluded that a combination of cytomorphologic features supported by either ancillary studies or correlation with clinical, radiologic, and laboratory findings are important in establishing a correct diagnosis of parathyroid tissue. The main diagnostic features in the current study also included bare nuclei.…”

“…2 One case series also found similar features. 4 Dimashkieh and Krishnamurthy reported that nuclei measuring smaller than thyroid follicular cells, bare nuclei, stippled chromatin, and a prominent vascular network with adherent cells indicated parathyroid origin. 5 Another study found vascular proliferation, bare nuclei, intracytoplasmic fat vacuolation, and high cellularity to be significantly associated with parathyroid origin.…”

Identification of parathyroid tissue in thyroid fine‐needle aspiration: A combined approach using cytology, immunohistochemical, and molecular methods

“…All samples were submitted as a thyroid nodule FNA, and represented 0.12% of the total thyroid FNAs examined over this period. Using previously published criteria, 47 samples (78%) displayed cytologic findings that were suggestive of PT cells, and were subsequently confirmed with IHC. Thirteen (13) samples (22%) had cytologic features that were not recognized as PT on initial ThinPrep evaluation and were classified using TBSRTC criteria as either AUS or SFN.…”

“…The cytologic features of parathyroid (PT) cells have been well described, both in conventional smears and in liquid‐based preparations . However, ectopic PT within the thyroid gland can be difficult to recognize, as both are neuroendocrine glands and show similar cytologic features .…”