ESA-SRB-AOTA 2019

Primary thyroid lymphoma: an uncommon cause of compressive goitre (#583)

Kay Hau Choy 1 , Jane Zhang 2
  1. Department of Endocrinology and Metabolism, Concord Repatriation General Hospital, Concord, NSW, Australia
  2. Department of Endocrinology, Wollongong Hospital, ISLHD, Wollongong, NSW, Australia

Case: An 85-year-old female presented with stridor on a background of enlarging neck mass over six weeks. Apart from lethargy, there were no symptoms of hypothyroidism. She reported a family history of hypothyroidism and thyroid cancer. Her stridor resolved following a dose of nebulised adrenaline. Blood tests showed profound hypothyroidism with thyroid-stimulating hormone of 170 mIU/L (reference range, 0.2–4.2), undetectable thyroid hormone levels and raised thyroglobulin antibodies, in keeping with Hashimoto’s thyroiditis. CT scan revealed a large goitre with mass effect on the pharynx at the level of the hyoid, leading to narrowing of the trachea. Ultrasound-guided core biopsy of the thyroid gland and flow cytometry showed features consistent with a B-cell non-Hodgkin’s lymphoma. A subsequent whole-body CT scan demonstrated paratracheal lymphadenopathy with no lymphadenopathy or malignancy elsewhere. She was started on levothyroxine as well as R-CHOP chemotherapy which she tolerated well. She became biochemically euthyroid 3 months later and continued to have regular endocrinology and haematology follow-ups.

Discussion: Primary thyroid lymphoma (PTL) is a rare cause of malignancy, accounting for only 5% of all thyroid malignancies and <2% of extranodal lymphomas, with an annual incidence of 1-2 cases per million.1,2 PTL usually occurs in the 7th-decade age group and is four times more prevalent in women. Patients with Hashimoto’s thyroiditis have a 40-80-fold increased risk of developing PTL.2,3 The most common presentation is a rapidly enlarging painless goitre. Ultrasonography is the initial diagnostic modality and cross-sectional imaging is indicated in the presence of compressive symptoms. Fine needle aspiration cytology, using flow cytometry and immunohistochemistry, remains the key modality used for diagnostic confirmation. Treatment is dictated by histological classification. Multimodal treatment with rituximab and combination chemoradiation therapy provide the highest overall survival rates. Prognosis is generally excellent but may vary due to the heterogeneous nature of PTL.1-3

  1. Stein SA, Wartofsky L. Primary thyroid lymphoma: a clinical review. J Clin Endocrinol Metab. 2013;98: 3131-8.
  2. Mehta K, Liu C, Raad RA, Mitnick R, Gu P, Myssiorek D. Thyroid lymphoma: A case report and literature review. World J Otorhinolaryngol. 2015;5: 82-9.
  3. Peixoto R, Pinto JC, Soares V, Koch P, Gomes AT. Primary thyroid lymphoma: A case report and review of the literature. Ann Med Surg. 2017;13: 29-33.