Endocrine Abstracts

Introduction: Pregnancy is not considered as a risk factor for recurrence in a previously treated DTC with excellent response to therapy. However, in cases of structural or/and biochemical incomplete response, diligent monitoring is of value including, neck ultrasound (U/S), thyroglobulin (Tg) and Tg-antibodies assessment, especially in cases of distant metastatic disease where scarce data exist.

Case report: A 27-year-old female patient was diagnosed in 12/2017 with a left lobe papillary thyroid carcinoma (max diameter (d): 5 cm, infiltrative follicular pattern without extrathyroidal extension). Whole body scan (WBS) after radioiodine (RAI) (03/2018, 100 mCi) revealed uptake in the thyroid bed and lower lung fields (LLFs) (Tg: 227 ng/ml, TSH: 59.4 mUI/mL). 4 nodules (d < 5 mm) in the LLFs were documented in a chest computed tomography (CT) scan while a hypoechoic left cervical lymph node (LN) (d: 0.50 x 0.36 cm) was revealed in the U/S. 7 months (mos) after RAI (10/2018 - Tg: 1.94 ng/ml, TSH < 0.01 mUI/mL), diagnostic WBS under recombinant human TSH was negative for abnormal uptake (Tg: 7.64 ng/mL, TSH: 82.7 mUI/mL). During re-evaluation (07/2020 - Tg: 4.3 ng/mL, TSH < 0.01 mUI/mL) chest CT revealed suspicious nodule (d < 0.5 mm) of the left LLF (lingula) and a left axillary LN (d:11 x 4 mm), while neck U/S remained unchanged. In 02/2021 first pregnancy was documented (TSH throughout pregnancy: 0.01 - 0.03 mUI/mL); a gradual increase in Tg was observed to a maximum level of 32.6 ng/mL, noted one month after a healthy female offspring was delivered. Tg progressively decreased 3 mos later (19.1 ng/mL) without any therapeutical intervention. Nevertheless, due to persistently elevated levels (18 - 20 ng/mL) with unchanged neck U/S, second RAI (03/2022 - 150 mCi) was performed revealing uptake in the LLFs (Tg: 120 ng/mL, TSH: 43 mUI/mL). ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) - CT 5 mos later (08/2022 - Tg: 10.2 ng/mL, TSH: 0.01 mUI/mL), revealed nodules in, the left LLF (lingula) and the right middle lung lobe with, moderate/low and high FDG uptake, respectively; no remarkable change of the axillary and cervical LNs. In 11/2022 second pregnancy was documented (TSH throughout pregnancy: 0.01 - 0.05 mUI/mL); a gradual increase in Tg was afresh observed to a maximum of 115.36 ng/mL, noted one month after a healthy female offspring was delivered; Tg decreased 2 mos later to 54.52 ng/mL without any therapeutical intervention. ¹⁸FDG PET-CT revealed multiple nodules in the LLFs (d: 5 - 10 mm).

Conclusions: Two consecutive uncomplicated pregnancies led to the delivery of healthy offsprings in a female DTC patient with distant metastatic disease. Tg elevation during pregnancy was followed by structural disease progression, however, decrease to more than half, prior to any therapeutic intervention, possibly suggests that pregnancy related factors may wield a direct effect on Tg levels. Larger studies with similarly selected DTC patients are needed towards evidence-based counseling of this patient subgroup.