Endocrine Abstracts

Aim: The aim of our study was to assess the correlation between pre-operative fine needles aspiration based cytology with post-operative histology in patients with thyroid nodules.

Methods: A retrospective analysis of patients who had thyroidectomy (hemi, subtotal, or total) was conducted and information on histology was obtained. Pre-operative FNA (done once or twice) was also obtained and compared with histology. Patients operated for Graves’ disease or completion thyroidectomy were excluded from analysis.

Results: 334 patients were identified – total thyroidectomy 36, subtotal 30, lobectomy/hemithyroidectomy 252, and other type of surgeries 16.28% (n=95) were malignant lesions.

One Pre-op Cytology:

Thy1 (N=96): Cyst 1%; benign nodule 84%; malignant 15%.

Thy1c (n=23): Cyst 4%: benign 78%; malignant 18%.

Thy2 (n=64): Cyst 3%; benign 86% and malignant 11%.

Thy3 (n=110): benign 67%; malignant 33%.

Thy4/5 (n=41): Cyst 2%, benign 15%, and malignant 83%.

In patients with malignancy, cytology was: Thy1 19%, Thy2 7%, Thy3 38%, and Thy4/5 36%.

Two Pre-op cytology:

59 patients had two FNAs done preceeding surgery.

Malignancy on histology was present in 14; of these, only 2 (14%) had at least one cytology of Thy4 or above (14%); 11 patients (79%) had at least one Thy3 or above; 3 (21%) had Thy1 on both occasions

Conclusion: There is significant discordance between cytology and histology in patients with thyroid nodule. Single Thy1 samples need to be investigated due to the risk of undiagnosed malignancy. Single cytology sample may miss 26% and even double cytology could miss 21%. A multi-disciplinary approach supported by multi-faceted evidence from history, clinical examination, radiology, and histopathology is required in patients with thyroid nodules.