Autonomously functioning thyroid nodule: a patient-based review

Abstract

Autonomously Functioning Thyroid Nodule (AFTN) is a rare cause of hyperthyroidism. AFTN, first described by Emil Goetsch in 1918, is the presence of a single hyperfunctioning thyroid nodule, which is not under the control of the pituitary/thyroid axis. The current theory on the development of hyperfunctioning nodules is the constitutive activation of Thyroid Stimulating Hormone Receptor (TSHR) due to a somatic point mutation and mutations of Gsa. The reported incidence of AFTN is about 1% on the investigation of thyroid nodules. Only about 10% - 30% become hyperfunction. Due to the rarity and lack of understanding of its characteristic clinical behaviour, AFTNs are often overlooked and undertreated. The ensuing review is based on a 36-year-old female who underwent left hemithyroidectomy for an AFTN and is well to date. There are two main issues in the diagnosis and management of AFTN. The first is that the diagnosis is not always made as most patients with AFTNs are functionally euthyroid. The other is the paucity of data in the literature to offer evidence-based individualized management for patients. As there are no tissue diagnostic criteria for AFTN; clinical, biochemical and radiological assessments to establish TSH independent nodular hyperfunction will clinch the diagnosis. Surgery and Radioiodine ablation remain the main forms of treatment for AFTN. Other methods such as percutaneous ethanol injection therapy (PEIT), laser ablation (LA), radiofrequency ablation (RFA) have a limited role in the management of an AFTN. The newer methods alluded to above will need further evaluation and a better definition of exact roles in the management of an AFTN.