Thyroid Carcinoma Arising Within a Background of Diffuse Hashimoto’s
Thyroiditis in the Paediatric Population.
J E Coulston, R J Egan, J D Morgan.
Department of Endocrine Surgery, North Bristol NHS Trust, Bristol, BS10 5NS
Diffuse hashimoto’s thyroiditis is rare in children, although its true epidemiology is not well understood. In the adult population, Hashimoto’s thyroiditis is associated with an increased risk of thyroid malignancy, especially papillary carcinoma. Follicular carcinoma is uncommon in the paediatric population and when found in association with diffuse Hashimoto’s thyroiditis has very rarely been described.
We present a case of a 14 year old female patient with a 3 month history of a mass in the lower neck. The patient had no significant past medical history of note but complained of a prodromal ‘flu-like’ illness 4 months prior to presentation. On examination there was a palpable nodule in the left lower lobe and ultrasound scanning confirmed a 3.5cm nodule in the lower pole of the left thyroid. It also revealed background changes throughout both lobes of the thyroid gland suggestive of thyroditis. Antithyroid peroxidise antibodies were strongly positive and thyroid function assays showed a normal T4 level with a raised TSH level.
Fine needle aspiration cytology (FNAC) revealed follicular cells and colloid, and a thyroid lobectomy was performed. Histology confirmed follicular carcinoma with a background of Hashimoto’s thyroiditis. A completion thyroidectomy was performed and diffuse thyroiditis was again present with no evidence of further malignant disease. 5 years following surgery there is no evidence of recurrent disease.
The small number of cases and the lack of good epidemiological data on the incidence of Hashimoto’s in the paediatric population makes the analysis of thyroid neoplasia in this context more difficult. Case study data has been published reporting the coexistence of the two thyroid pathologies with the majority of cases reporting papillary carcinoma similar to the adult population. Hashimoto’s often has a more benign clinical course in the paediatric population but potentially these patients are at a greater risk of developing a thyroid malignancy and follow up should therefore be adjusted accordingly.