Endocrine Abstracts

Introduction: Follicular thyroid cancer (FTC) is a tumour of the thyroid epithelium with follicular differentiation and invasion into capsule or vessels. Constitutes 10% of all thyroid cancers, may be minimally or widely invasive. metastases in 20% of cases by haematogenous spread, rarely to lymph nodes. Twice as common in females as males, mean age 50years. Treated with thyroidectomy, radioactive iodine ablation and TSH suppression with levothyroxine.

Case Description: 34 year lady, background Asthma on asthma inhalers, epilepsy-off medications since age 17years, Found to have 5 cm thyroid nodule, U2 in June 2020 and Normal thyroid function during an inpatient stay with appendicitis. She felt nodule was bigger during an asthma attack in December 2022, euthyroid clinically with enlarged right lobe of thyroid. Repeat USS showed 5 cm thyroid nodule in right lobe with U3 features, FNAC Reported Thy 2-normal. Since cytology report and USS features incongruent a repeat FNAC was requested. Unfortunately, 2 nd FNAC reported Thy1-insufficient sample. 3 rd FNAC done reported Thy 3f-indeterminate for follicular cancer. Discussed with patient on need for surgery; all results communicated to patient at each stage. She had right hemithyroidectomy in April 2023. Histology returned Follicular thyroid cancer, PT3a, pNx, pMx, Pv1, pRx. Discussed in the Thyroid cancer MDT and Completion thyroidectomy with Radio-active iodine ablation recommended. She was booked for completion thyroidectomy but incidentally found to be pregnant during anaesthetic assessment. She decided to keep the pregnancy so plans for completion thyroidectomy deferred till after delivery of the baby. Seen at 14 weeks gestation with TSH 2.4 and FT4 10.1 pmol/l. She was started on levothyroxine 50 mg with aim to get TSH under 2 miu/l and for further review by surgical team on delivery. USS Thyroid June 2020 5.1 × 3.0 × 2.5 cm isoechoic nodule with a halo and predominantly peripheral vascularity in right lobe of thyroid (U2). No retro-sternal extension. January 2023 5.1 cm × 2.6 cm × 2.8 cm right thyroid nodule, no real change since previous scan, slight heterogeneity of the nodule with some internal vascularity; in view of the patients age, the nodule reclassified U3 and FNA performed. No lymphadenopathy. Histology Encapsulated angio-invasive follicular thyroid carcinoma, 50 mm maximum dimension, tumour in the inferior shave margin, incomplete excision. Pathological staging pT3 a pNx pMx pV1 pRx.

Learning points: Important not to overlook patient symptoms even though in this case the size of the nodule was unchanged, features had changed. Repeat investigations essential if results of USS and cytology incongruent