Cytomorphologic features distinguishing Bethesda category IV thyroid lesions from parathyroid

Simon Sung, Anjali Saqi, Elizabeth Margolskee, John Crapanzano

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Background: Thyroid follicular cells share similar cytomorphological features with parathyroid. Without a clinical suspicion, the distinction between a thyroid neoplasm and an intrathyroidal parathyroid can be challenging. The aim of this study was to assess the distinguishing cytomorphological features of parathyroid (including intrathyroidal) and Bethesda category IV (Beth-IV) thyroid follicular lesions, which carry a 15%-30% risk of malignancy and are often followed up with surgical resection. Methods: A search was performed to identify 'parathyroid' diagnoses in parathyroid/thyroid-designated fine-needle aspirations (FNAs) and Beth-IV thyroid FNAs (follicular and Hurthle cell), all with diagnostic confirmation through surgical pathology, immunocytochemical stains, Afirma® analysis, and/or clinical correlation. Unique cytomorphologic features were scored (0-3) or noted as present versus absent. Statistical analysis was performed using R 3.3.1 software. Results: We identified five FNA cases with clinical suspicion of parathyroid neoplasm, hyperthyroidism, or thyroid lesion that had an eventual final diagnosis of the parathyroid lesion (all female; age 20-69 years) and 12 Beth-IV diagnoses (11 female, 1 male; age 13-64 years). The following cytomorphologic features are useful distinguishing features (P value): overall pattern (0.001), single cells (0.001), cell size compared to red blood cell (0.01), nuclear irregularity (0.001), presence of nucleoli (0.001), nuclear-To-cytoplasmic ratio (0.007), and nuclear chromatin quality (0.028). Conclusions: There are cytomorphologic features that distinguish Beth-IV thyroid lesions and (intrathyroidal) parathyroid. These features can aid in rendering correct diagnoses and appropriate management.

Original languageEnglish (US)
Article number10
Issue number1
StatePublished - 2017
Externally publishedYes


  • Bethesda category IV
  • cytology
  • fine-needle aspiration
  • parathyroid
  • thyroid

ASJC Scopus subject areas

  • Pathology and Forensic Medicine


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