Diagnostic Tools Applied to Determine Thyroid Lipoadenoma: A Case Report

We report a case of thyroid lipoadenoma of the thyroid gland, an extremely rare benign lesion containing both adipose tissue and thyroid tissue. A 74-year-old Chinese female underwent a series of examinations for the incidental thyroid nodule. The sonogram showed a well-encapsulated and hyper-isoechoic nodule in the left thyroid gland. The CT revealed a low-attenuation thyroid nodule without evidence of extrathyroid extension. Fine-needle aspiration (FNA) cytology reported atypia of undetermined significance. As none of these studies could confirm the diagnosis and rule out potential malignancy, the patient ultimately received minimally invasive video-assisted thyroidectomy (MIVAT). Final pathology confirmed the diagnosis of thyroid lipoadenoma, consisting of adipose tissue and follicular cells, with adipose tissue comprising approximately 40% to 50% of the lesion. Common diagnostic tools for thyroid nodules offer limited utility in identifying thyroid lipoadenoma, often requiring thyroidectomy for definitive diagnosis and management.