The present review deals with the functional roles of iodine and its metabolism. The main biological function of iodine concerns its role in the biosynthesis of thyroid hormones (THs) by the thyroid gland. In addition, however, further biological roles of iodine have emerged. Precisely, due to its significant action as scavenger of reactive oxygen species (ROS), iodine is thought to represent one of the oldest antioxidants in living organisms. Moreover, iodine oxidation to hypoiodite (IO⁻) has been shown to possess strong bactericidal as well as antiviral and antifungal activity. Finally, and importantly, iodine has been demonstrated to exert antineoplastic effects in human cancer cell lines. Thus, iodine, through the action of different tissue-specific peroxidases, may serve different evolutionarily conserved physiological functions that, beyond TH biosynthesis, encompass antioxidant activity and defense against pathogens and cancer progression.

Vitiligo represents the most common cause of acquired skin, hair and oral depigmentation, affecting 0.5-1% of the population worldwide. It is clinically characterized by the appearance of disfiguring circumscribed skin macules following melanocyte destruction by autoreactive cytotoxic T lymphocytes. Patients affected by vitiligo usually show a poorer quality of life and are more likely to suffer from depressive symptoms, particularly evident in dark-skinned individuals. Although vitiligo is a non-fatal disease, exposure of affected skin to UV light increases the chance of skin irritation and predisposes to skin cancer. In addition, vitiligo has been associated to other rare systemic disorders due to the presence of melanocytes in other body districts, such as in eyes, auditory, nervous and cardiac tissues, where melanocytes are thought to have roles different from that played in the skin. Several pathogenetic models have been proposed to explain vitiligo onset and progression, but clinical and experimental findings point mainly to the autoimmune hypothesis as the most qualified one. In this context, it is of relevance the strong association of vitiligo with other autoimmune diseases, in particular with autoimmune thyroid disorders, such as Hashimoto thyroiditis and Graves’ disease. In this review, after a brief overview of vitiligo and its pathogenesis, we will describe the clinical association between vitiligo and autoimmune thyroid disorders and discuss the possible underlying molecular mechanism(s).

Primary hyperparathyroidism (PHPT) is one of the most frequent endocrine diseases worldwide. Surgery is the only potentially curable option for patients with this disorder, even though in asymptomatic patients 50 years of age or older without end organ complications, a conservative treatment may be a possible alternative. Bilateral neck exploration under general anaesthesia has been the standard for the definitive treatment. However, significant improvements in preoperative imaging, together with the implementation of rapid parathyroid hormone determination, have determined an increased implementation of focused, minimally invasive surgical approach. Surgeons prefer to have a localization study before an operation (both in the classical scenario and in the minimally invasive procedure). They are not satisfied by having been referred a patient with just a biochemical diagnosis of PHPT. Imaging studies must not be utilized to make the diagnosis of PHPT. They should be obtained to both assist in determining disease etiology and to guide operative procedures together with the nuclear medicine doctor and, most importantly, with the surgeon. On the contrary, apart from minimally invasive procedures in which localization procedures are an obligate choice, some surgeons believe that literature on parathyroidectomy over the past two decades reveals a bias towards localization. Therefore, surgical expertise is more important than the search for abnormal parathyroid glands.