Incidence of carcinoma among THY3 lesions of the thyroid

Abstract

INTRODUCTION AND OBJECTIVES: Ultra Sound Scan (USS) and Fine Needle Aspiration Cytology (FNAC) of thyroid nodules are carried out in patients with goitre. THY3 lesions cause diagnostic difficulty and risk of malignancy in such lesions is 20%. The objective of this study was to determine the incidence of carcinoma among THY3 lesions and to relate the findings to the size of the nodule. METHOD: All the patients who underwent thyroidectomy at the University Surgical Unit, Colombo North Teaching Hospital from November 2002 to December 2015 were analysed retrospectively. Histological and ultrasonic data in patients with THY3 lesions were analysed. RESULTS: There were 29 (5.68%) THY3 patients among 510 patients who had thyroidectomy. Only 6 (20.7%) patients were histologically proven to be malignant (follicular carcinoma – 3, papillary carcinoma - follicular variant- 2, mixed medullary papillary carcinoma - 1). All patients were females (age range 17y -52y). Pre-operative USS nodule size in the malignant group ranged from 2.6 cm to 6.8 cm (average - 4.25cm). 20 patients (68.9%) had benign histology (MNG - 18, thyroiditis-2). USS nodule size in the benign group ranged from 2.3 cm to 2.5 cm. Three patients (8.7%) were lost to follow up. CONCLUSIONS: About 20.7% of THY3 lesions had thyroid carcinoma. Lesions larger than 4.25 cm were more likely to harbour a malignancy.