Endocrine Abstracts

Background: Anaplastic carcinoma and primary lymphoma (TL) each constitute <2% of thyroid malignancies and are difficult to distinguish clinically. Both typically present with rapidly enlarging anterior neck masses in the elderly. Both may cause pressure symptoms (e.g. dysphagia, stridor and hoarseness). Differentiation is imperative as their treatment and prognoses differ.

Case report: A 68-year-old man presented with a rapidly enlarging thyroid mass, pressure symptoms and an ipsilateral Horner’s syndrome (HS). His past history included primary biliary cirrhosis. Clinical examination revealed a fixed 7 cm thyroid mass with no lymphadenopathy. Bloods revealed thyroid stimulating hormone 15 mIU/l, thyroxine 7.6 mIU/l and lactate dehydrogenase 636 μ/l. Full blood count, smear and serum thyroid antibodies were normal. Indirect laryngoscopy demonstrated a right cord paresis. Fine needle aspiration (FNA) demonstrated mononuclear and atypical cells.

Ultrasound-guided core biopsy revealed diffuse large B-cell lymphoma. Whole body CT demonstrated a large thyroid mass, tracheal deviation with no evidence of lymphadenopathy. Within 5 days of commencing chemotherapy (rituxumab/cyclophosphamide/doxorubicin/vincristine/ prednisolone; R-CHOP) his neck swelling was impalpable. He received external beam radiotherapy. His hoarse voice resolved within a month. The patient is now almost disease free with no clinical sign’s of HS at 1-year follow-up.

Discussion: HS in association with thyroid lymphoma has not been reported in the English literature. TL is associated with Hashimoto’s thyroiditis, and other auto-immune disorders such as in our case. TL is almost exclusively B-cell in origin: non-Hodgkins type; 71% (aggressive); or mucosa associate lymphoid tissue (MALT); 28% (indolent). Even though FNA is the accepted first line histological investigation for thyroid masses, core or incisional biopsy may be necessary when FNA is inconclusive. Treatment regimes (typically chemotherapy±radiotherapy) differ for histological sub-types of lymphomas. 5-year failure-free survival is up to 90% in TL compared with a mean survival of 6 months in anaplastic carcinoma.