THYROID CANCER TUMOR BOARD: Discordant Cytopathological Diagnosis of Well-Differentiated Thyroid Cancer Affects Patient Treatment

A teenage girl had been diagnosed with Hashimoto’s thyroiditis and a thyroid nodule about 2 years ago. She has a family history of autoimmune thyroid disease, and a grandmother also had a goiter. Her thyroid function was normal on presentation. A neck ultrasound revealed a 3-cm nodule Fine-needle aspiration under ultrasound guidance was performed and cytology was consistent with follicular lesion of undetermined significance (FLUS). She sought several opinions for management of this nodule, and ultimately a decision was made to monitor it. Nine months later, a repeat ultrasound demonstrated growth of the nodule that then measured 4 cm in maximum dimension (Figure 1). A repeat biopsy with molecular testing revealed follicular neoplasm, benign Afirma gene expression classifier and negative MiRInform molecular panel. Because of the increase in nodule size and indeterminate cytology, a hemithyroidectomy was performed. Surgical pathology demonstrated a 4.5-cm minimally invasive follicular thyroid carcinoma (FTC) with a focus of vascular invasion. The margins were free of tumor. Also noted were foci of cellular architectural atypia, including insular and/ or solid patterns.