Endocrine Abstracts

Introduction: Lymphoma usually occurs within lymph nodes, but in rare cases, it arises from lymphocytes that are presented within the thyroid gland. Thyroid lymphoma is rare, representing less than 5% of thyroid malignancies and less than 2% of all lymphomas occurring outside of the lymph nodes and it is more likely to occur in people with Hashimoto’s thyroiditis. In this case we present a patient with Hashimoto’s thyroiditis (HT) and thyroid lymphoma (TL).

Case: 63 years women presented to the outpatients clinic with complains of fatigue, weakness of voice and enlargement of the neck. She has autoimmune thyroiditis (anti-TPO 53 kU/l) for 10 years. She has been taking Levothyroxin 50 μg per day for 5 years. Few weeks ago, she had noticed painless fast swelling left side of the neck and after 2 weeks the enlargement of the right side of the neck. Physical examination showed a large palpable mass on the both sides of the neck and an enlarged thyroid. Laboratory studies showed elevated sedimetation rate 34 mm/h (normal <13 mm/h), elevated anti-TPO antibodies 689kU/l (0–12) and anti-Tg 682 kU/l (0–100). Other laboratory measurements, including haemoglobin and leukocytes, thyroid hormones (FT4 15.22 pmol/l (12–22), TSH 0.72 mU/l (0.27–4.2), anti-TSH-R 3U/l (<9)), calcitonin <0.42 pmol/l (0–2.8), were normal. In the thyroid ultrasound examination thyroid enlarged, hypoechoic, heterogeneous, in the left side pathological lymph nodes – suspicion of lymphoma or anaplastic carcinoma. Other radiological tests, including abdomen ultrasound, chest X-ray and mammography, evaluating the spread of oncological process, were normal. Core needle biopsy of the thyroid was taken and showed a Diffuse large B-cell lymphoma (DLBCL). PET-CT scan showed metabolically active lymphoproliferative process in the thyroid, in the lymph nodes of mediastinum, in the small intestine and in the mesenteric lymph nodes. The patient was diagnosed with DLBCL (non Hodgkin’s lymphoma) stage IV IPI 4 of the thyroid with hypothyroidism. Treatment with R-CHOP21 (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone) chemotherapy was started. After the first course of chemotherapy thyroid enlargement regressed, after the third course of chemotherapy anti-TPO antibodies decreased to 85kU/l, anti-Tg decreased to 55 kU/l, the thyroid function remained stable and in the thyroid ultrasound only the signs of thyroiditis is observed.

Conclusions: This case proves that TL, although rare, should always be considered in the differential diagnosis of patients with fast thyroid enlargement, nodules, goiter and carcinomas, because its prognosis and treatment differ substantially from the other disorders.