Endocrine Abstracts

Case Information: A 39-year-old woman from Guatemala with no significant past medical history initially presented with swelling in neck & obstructive symptoms. She was diagnosed with papillary thyroid carcinoma in March 2017 & underwent a total thyroidectomy& LN Dissection. Pathology showed multifocal, largest tumor size 3.2 cm, with one involved lymph node, significant angiolymphatic invasion, and was stand was staged as initially received 121 mCi of radioactive iodine ablation in April 2017. However, she developed recurrence and disease progression over a five-year course are summarized below.

Investigations: • Dec 2017 -US Neck mapping - 2 abnormal nodules in lower left thyroid fossa, persistently abnormal speculated lymph node cluster in left mid-neck. FNAB of the Thyroid nodule, LN - Negative for malignancy, TSH <0.1 • Nov 2018 US Neck mapping showed cystic degeneration of lymph nodes 35 mm, and stable thyroid nodules in left fossa, TSH <0.1 • Feb 2019 US Neck showed stable/smaller left lymph node with progressive cystic change. • Dec 2019 Abnormal left internal jugular chain node. Biopsy positive for MALIGNANCY. Plan was to proceed with LN Dissection, WBS. Surgery was delayed due to COVID Pandemic and family issues. • June 2020 shows the stability of left internal jugular LN • Oct 2020 LN Dissection, total of 6 lymph nodes 1 in Level 4, 3 in Level 2, and 2 in Level 3 positive for PTC with extracapsular extension. • Feb 2021 stimulated TG 21.6,125 mci of RAI; pretreatment scan with 0.4% uptake, WBS scan with no abnormal uptake. • Nov 2021 The previously visualized left thyroid fossa nodule is stable. There is a larger bilobed nodule; suspicious nodules are present. • Dec 2021 PET /CT - Focal FDG avidity within left paratracheal region associated with a small amount of soft tissue thickening is suspicious for recurrent malignancy. FDG Activity in left external iliac & inguinal Lymph node, CT neck with enlarged left level 1B LN and 7mm left thyroid fossa • Feb 2022 FNAB of left thyroid fossa lesion 2/22 positive for malignancy. CT Thorax/ Abdomen/ Pelvis- Negative, She was started on Lenvatinib 24mg daily, had S/E hand-foot syndrome, and Lenvatinib was reduced to 14mg daily. Radioiodine (RAI)-refractory thyroid cancer is extremely rare, with an incidence of 4-5 cases per million a year. This case illustrates the challenging management of radioiodine-refractory DTC in a 39-year-old woman with recurrence. Further clinical trials investigating alternative therapies in the treatment of RAI-R thyroid cancer would be of great benefit to patients seeking treatment.