Endocrine Abstracts

Introduction: As the incidence of thyroid cancer is increasing, so are the cases of recurrence with RAI refractory metastasis of thyroid differentiated cancer. We present such a case

Case report: A 77-year-old female with a medical history of papillary thyroid carcinoma recurrence 10 years after surgery with successful 3 RAI sessions and normal thyroid cancer markers after treatment until her recurrence a year ago, with TSH unstimulated thyroglobulin of 199 ng/ml. She had extensive cervical surgery with en-block resection and jugular grafting because of laterocervical adenopathies with Bethesda V suspicion of papillary carcinoma. After surgery we referred her to radio iodine treatment.

Laboratory: thyroglobulin of 255 ng/ml, on stimulated TSH of over 100, thyroglobulin antibodies of 5.8.

Whole body I131 scintigraphy: anterior thyroid recurrence.

She received 160 mCi of I131 and as the thyroglobulin remained high the nuclear imagist ordered more imagining.

The cervical and thoracic CT revealed multiple bilateral secondary lesions in the lungs and large supraclavicular adenopathies, with no other primary tumor.

The abdominal and pelvic IRM was normal.

The oncologist repeated the thyroglobulin and the thyroglobulin was 38.9 ng/dl with a TSH of 16, 6 weeks after radioiodine treatment and the decision was to repeat the CT in 2 months.

The new cervical and thoracic CT showed a progression of the pulmonary lesions so the patient was referred to the nuclear imagist with a suspicion of RAI resistant metastasis.

Conclusion: Typically differentiated thyroid cancer has a good prognostic with 5-year survival rate of over 98%, but almost one third of recurrences become RAI resistant with a 5-year survival of only 19%. There is a BRAF mutation that promotes NIS silence in these cases so it is very important to identify these patients as to avoid unnecessary irradiation and waist precious time that could be used with trying new individualized treatment.