Hemiagenesis of the Thyroid in a Seven-year-old Child: A Case Report

Thyroid Hemiagenesis (TH) is a rare condition characterised by developmental abnormalities of the thyroid, often observed on the left-side, with a higher prevalence in females. It is commonly associated with a lack of the isthmus. A seven-year-old boy presented to the Ear Nose Throat (ENT) Department with chief complaints of bilateral ear block sensation and dull aching earache persisting for two months, for which syringing was performed. No family history of TH or any past surgeries related to the neck, thyroid, or parathyroid were reported. In recent laboratory tests, his Thyroid Stimulating Hormone (TSH) level was 7.23 mu IU/mL, free tetraiodothyronine was 8.91 mcg/dL, free triiodothyronine was 75.06 ng/dL, and Antithyroid Peroxidase (TPO) was 2.0 IU/ mL. The neck ultrasound revealed the absence of the left thyroid lobe and isthmus. He was diagnosed with congenital TH and hypothyroidism and was treated with a dosage of 25 mcg of levothyroxine. TH can be incidentally discovered and may manifest in later stages of life. Patients with TH are more prone to developing hypothyroidism compared to individuals with a complete thyroid, as they have lower reserves of thyroid hormones.