Background:
Ultrasound-guided fine needle aspiration (USS-FNAC) is the gold standard when evaluating patients with thyroid nodules, however, the utility of USS-FNAC in the evaluation of Intrathoracic Goitres (ITG) remains controversial. 

Objectives:
To evaluate the value of USS-FNAC in determining the incidence of cancer within ITG.

Methods: 
Single unit analysis of 237 consecutive patients undergoing surgery for ITG from 2004 to 2016 was conducted. Data on cytological and histological analysis was collected prospectively and analyzed.

Results:
Nineteen patients were diagnosed with thyroid cancer. The rate of malignancy in ITG was 8.02%. Twelve patients had benign pre-operative benign cytology results resulting in a rate of unexpected occult malignancy of 5.0%. The USS-FNAC had a sensitivity of 33% and specificity 93.3% to exclude cancer.

Conclusion:
USS-FNAC has poor sensitivity but high specificity to exclude cancer in ITG.

The role of Ultrasound-guided Fine Needle Aspiration Cytology in preoperative diagnosis of malignancy in Intrathoracic Goitre