In many centers thyroid lobectomy alone is increasingly being performed for patients with follicular variant of papillary thyroid carcinoma (fvPTC). However, there are few studies about the prevalence of contralateral disease in these patients. We performed a retrospective review of patients who underwent thyroid surgery in Acibadem University during the period of 2010-2017 with a diagnosis of fvPTC (invasive/ I-fvPTC and non-invasive/NIFTP-Noninvasive Follicular Thyroid Neoplasm With Papillary-Like Features) as their primary lesion. We collected information regarding patient demographics, nodule size, multifocality, fine needle aspiration (FNA) results, lymphovascular invasion (LVI), extrathyroidal extension (ETE), and lymph node metastasis. We identified 94 patients with final pathology demonstrating NIFTP (n=74) and invasive I-fvPTC (n=20).

Sixteen contralateral tumours (17% of the cases) were identified: 6 PMC-FV (Papillary microcarcinoma-follicular variant), 5 classical PTC (papillary thyroid carcinoma), 3 I-fvPTC and 2 NIFTP.

In conclusion, bilateral disease is common in fvPTC (in 14 cases the primary lesion was NIFTP and in 2 invasive fvPTC) primarily in the form of invasive disease (n=14). Close monitoring of the contralateral lobe should be considered with patients with fvPTC, particularly NIFTP cases, who do not perform total thyroidectomy.