Objective : To assess the use of thyroglobulin (TG) monitoring in thyroid cancer surveillance after lobectomy in the setting of chronic lymphocytic thyroiditis.
Clinical data of the patient are presented.
A 20-year-old female presented after left lobectomy in 2014 for a T1N0Mx minimally invasive follicular carcinoma. She was diagnosed at age 16 with a 2.8x3.9x3.1 cm left thyroid nodule and a right 0.7 cm hypoechoic nodule. Fine needle aspiration (FNA) of the left thyroid nodule revealed microfollicular tissue fragments. She underwent left lobectomy demonstrating a minimally invasive 5 cm follicular thyroid cancer with focal capsular and vascular invasion, no extrathyroidal invasion or nodal involvement, background chronic lymphocytic thyroiditis.
On her follow up, labs showed TSH 2.08 uIU/ml, TG antibody 1.8 IU/ml, TG 180 ng/ml via immunoassay (athyrotic <0.1 ng/ml, < 33 ng/ml intact thyroid), TG by mass spectrometry > 250 ng/ml (athyrotic < 0.5 ng/ml, < 33 ng/ml intact thyroid). Neck US showed 6x 6x6 mm solid hypoechoic nodule in the left thyroid bed, 6x6x10 mm hypoechoic solid nodule in the right medial lobe, the biopsy of which suggest a pleomorphic lymphocytes with no follicular cells. A CT chest showed no evidence of lung metastases. The patient was referred for completion thyroidectomy based on her initial risk of tumor size (5 cm), and young age at presentation (16 yrs).
Discussion : TG monitoring after subtotal thyroidectomy is endorsed by the ATA 2015 guidelines on the management of thyroid cancer. After lobectomy, the expected TG value is 15 ng/ml which was exceeded in our patient in the absence of metastases. Patients with lymphocytic thyroiditis may have higher TG levels; however, the exact TG reference range for chronic lymphocytic thyroiditis has not been established.
Conclusion : With the increasing rates of low risk differentiated thyroid cancer, more studies are needed to individualize surveillance in patients with hashimoto’s thyroiditis undergoing lobectomy. We suggest obtaining baseline thyroglobulin levels as one way of doing that.
St Louis, Missouri
I'm a second year Endocrine fellow at Washington University
Saint Louis, Missouri
Dr Jasim completed her Endocrine fellowship at the Mayo clinic in Rochester, MN and She is currently an Assistant professor of Medicine in the Division of Endocrinology, Metabolism and Lipid Research at Washington University in St. Louis School of Medicine. She is running the thyroid clinic and Endocrine neoplasia with focus on Thyroid cancer, MEN syndromes and Adrenal tumors