Ultrasound prevalence and characteristics of incidental thyroid lesions in Nigerian adults

Thyroid lesions are common and range from the incidental, asymptomatic, small solitary nodule to the large and partly intrathoracic masses. Thyroid lesions that are not palpable but identified by radiological imaging for unrelated symptoms are defined as incidentalomas of the thyroid gland.

The aim of this study was to determine the ultrasound prevalence of thyroid incidentalomas and describe the ultrasound characteristics of such detected incidentalomas in Nigerian adults.

This was a prospective study that examined 340 subjects over a period of 6 months. They were selected randomly from volunteers and patients presenting for ultrasound examination of other parts of the body. The subjects had their necks examined by palpation and ultrasound in the department of Radiology, University College Hospital, Ibadan, using a General Electric LogicP5 ultrasound machine with a 6-10 MHz linear transducer. Any incidentaloma detected was classified using the 'Thyroid Imaging Reporting and Data System' (TIRADS) classification.

Three hundred and forty (340) subjects comprising of 153 males and 187 females were examined. The ultrasound prevalence of thyroid incidentalomas was 22.4%. Thyroid incidentalomas were more common in females than males but this was not statistically significant. The prevalence of thyroid incidentaloma significantly increased with age up to the seventh decade. Majority of the lesions were solitary, homogenous and cystic.

The ultrasound prevalence of thyroid incidentalomas documented in the study area is high (22.4%) and they were commoner in women and older subjects. Majority of the lesions, 41 (53.95%) were classified as TIRADS 2 (benign lesions).