Endocrine Abstracts

Objectives: The macrofollicular variant of papillary thyroid cancer (MFV-PTC) is a rare subtype often lending to a challenging diagnosis. This study evaluated the ultrasonographic (US) features and clinical implication of MFV-PTC.

Methods: Records of 14 patients histologically diagnosed with MFV-PTC at our institution over a period of 16 years were retrospectively reviewed. Preoperative US features, Bethesda categories determined by fine-needle aspiration (FNA) or core needle biopsy (CNB), and final pathology were assessed in all patients with MFV-PTC.

Results: Most nodules were noted as solid isoechoic on US and were categorized as low suspicion in 12 cases and intermediate suspicion in two cases. The median tumor size was 1.2 cm (range, 0.6–5.6 cm). Of the 14 MFV-PTC cases, 11 underwent FNA or CNB. Four (36.4%) with Bethesda category II or III underwent the follow up because of benign looking appearance on US and benign results in subsequent CNBs. However, the patients underwent delayed surgery (31.3 months, range 12–41 months) because of serially increased tumor size. Patients with seven nodules diagnosed as Bethesda type IV, V, and VI underwent subsequent surgery. Gross extrathyroidal extension into subcutaneous fat tissue and lateral lymph node metastasis were noted in a patient who underwent follow-up. No distant metastases or recurrence was detected.

Conclusion: MFV-PTC is representative of a benign sonographic appearance of PTC variants. Serial tumor growth is the only suspicious finding for MFV-PTC because FNA or CNB is often false negative.

Keywords: Thyroid nodule; Ultrasonography; Papillary thyroid carcinoma; Variant