Commonly forgotten complication of Hashimoto's thyroiditis.

Hashimoto's thyroiditis (HT) is a frequently encountered condition in clinical practice and management is generally uncomplicated with patients on a stable dose of thyroxine supplementation. However, complications of thyroid lymphoma can develop, though it is rare and hence commonly forgotten by physicians. We present a case of a patient with HT who developed thyroid lymphoma. A 61-year-old woman presented with an enlarged goitre complicated by compressive symptoms and was diagnosed with HT. She was treated with stable dose of thyroxine but her constitutional symptoms of weight loss prompted further investigations and diagnosis of diffuse large B-cell lymphoma was eventually made. She underwent chemotherapy and adjuvant radiotherapy and is currently in remission 1 year post-treatment. There should be an increased index of suspicion of primary thyroid lymphoma in patients with HT for early diagnosis and treatment for better outcomes. 2016 BMJ Publishing Group Ltd.