The diagnostic accuracy of fine-needle aspiration cytology for thyroid nodules is not affected by coexistent chronic autoimmune thyroiditis: results from a cyto-histological series of patients with indeterminate cytology

Abstract

Objective Indeterminate cytological result at Fine-needle-aspiration-cytology (FNAC) remains a clinical challenge for endocrinologists. Aim of the present study was to evaluate whether a coexistent Chronic-Autoimmune-Thyroiditis (CAT) might affect the diagnostic accuracy of fine-needle aspiration cytology for thyroid nodules. Design and Methods A retrospective cohort study was designed including all nodules receiving an indeterminate cytology result (TIR3A or TIR3B) undergoing thyroid surgery and subsequent histological confirmation. Patients were stratified in two groups according to the presence or absence of CAT. The hypothesis to be tested was whether follicular cell alterations induced by CAT might increase the rate of indeterminate cytological results in histologically benign thyroid nodules. Additional control groups were represented by nodules with determinate cytology, either benign (TIR 2) or malignant (TIR5). Results: One-hundred-eighty-nine indeterminate thyroid nodules were included (67 TIR3A and 122 TIR3B). At post-surgical histology 46 nodules (24.3%) were malignant. No significant differences were observed in the rate of histologically proven malignancy between patients without CAT and patients with CAT in the TIR3B (29.4% vs 32.4%; p=0.843) nor TIR3A (13.0% vs 11.4%; p=1.000) nodules. The rate of coexistent CAT was similar between TIR3B and TIR5 nodules harboring PTC at histology (30.4% vs 39.4%, p=0.491) and between indeterminate nodules and a control group of TIR2 nodules (39.2% vs 37.0%; p=0.720). Conclusions: The similar rates of histologically proven malignancy found in cytologically indeterminate nodules in the presence or absence of concomitant CAT, would not support that CAT itself affects the diagnostic accuracy of fine-needle aspiration cytology.

Hashimoto’s Thyroiditis Does Not Influence the Malignancy Risk in Nodules of Category III in the Bethesda System

“…Cho et al [38] found the same frequency of malignancy-48%-in patients with and without HT. Rotondi et al [39] also reported similar values-11.0% vs. 13.4%, respectively. Suh et al [40] and Mulder et al [28] observed that the frequency of malignancy in patients with HT was over 10 percentage points lower than the one in patients without HT (Suh: 36.0% vs. 46.6%, Mulder: 44% vs. 60%).…”

The Immune Landscape of Papillary Thyroid Cancer in the Context of Autoimmune Thyroiditis

“…There is overwhelming evidence that autoimmune thyroiditis affects PTC’s natural history [ 7 , 11 , 15 , 102 , 169 ]. Despite having been reported in numerous clinical studies, the concept of the significant association between autoimmune thyroiditis and PTC remains controversial [ 10 , 24 , 102 ]. A new model to elucidate this long-standing debate has been recently generated using a genetic approach to induce both thyroiditis and PTC [ 54 ].…”

“…Scholars have long debated whether this association represents the coexistence of two independent but common diseases that are brought together by the increased use of thyroid ultrasound and fine-needle aspiration, or if it instead reflects a true cause–effect relationship [ 10 , 11 , 12 , 13 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. Some studies have suggested that thyroiditis attenuates PTC severity [ 12 , 13 , 20 , 24 , 25 , 29 , 30 , 31 ], while others have concluded that thyroiditis promotes the progression of PTC [ 10 , 17 , 18 , 19 , 32 ]. Recently, McLeod et al [ 32 ] conducted a case-control study nested within the United States Army personnel who served between 1996 and 2014.…”

“…The molecular landscape of PTC is characterized by activating mutations in oncogenes, BRAFV600E being the most frequent (60%) followed by mutations in the different isoforms of RAS (8% of PTC), as well as gene fusions, such as RET/PTC [ 155 ]. Although the association between thyroiditis with PTC has been well-established [ 7 , 10 , 11 , 13 , 18 , 19 , 24 , 25 , 28 , 29 ], the definitive molecular link is still elusive.…”