Endocrine Abstracts

Primary thyroid gland lymphomas account for less than 5% of all thyroid malignancies. They mainly occur in the setting of lymphocytic thyroiditis or Hashimoto’s disease. The majority are mucosa-associated lymphoid tissue lymphomas and diffuse large B-cell lymphomas. There have not been any cases of thyroid lymphoma reported in children in the last 20 years.

Our patient is a 9-year-old boy who was noted to have a lump on the right side of his neck in November 2009. He was initially treated with oral antibiotics for a coexisting upper respiratory tract infection. As there was no improvement, he had thyroid function tests performed. TSH was 55.17 mIU/l and FT4 was 10.1 pmol/l. Thyroid Peroxidase antibodies were 74 IU/ml. He was commenced on Thyroxine. An USS showed an irregular and inhomogeneous mass in the right lobe of the thyroid gland measuring 4 cm×4 cm. Fine needle aspiration showed a thyroid lymphoma arising on a background of chronic lymphocytic thyroiditis.

As the mass rapidly increased in size, he was commenced on Prednisolone, which led to a reduction in the size of the mass. Bilateral bone marrow aspirates, trephine and CSF were negative. He had a CT scan of the neck and chest and a further biopsy which confirmed a B cell lymphoma showing a high proliferation index. He underwent hemithyroidectomy in April 2010. Histopathology revealed a residual necrotic nodule and Hashimoto’s thyroiditis. He has since completed treatment on the B-Non Hodgkin’s lymphoma protocol. In June 2010, he developed type 1 diabetes mellitus. He was positive for Islet cell antibodies but had normal GAD antibodies. He is currently on a basal bolus regimen.

We present a case of a thyroid lymphoma in a patient with Hashimoto’s thyroiditis. It is important to be aware of this rare complication and its association with other autoimmune disorders.