Benign thyroid lesions are cellular differentiation into enormous sizes that can be seen from the outside without interfering with thyroid hormone. The FNAB and USG were used to diagnose thyroid lesions. Unilateral benign lesions may be treated with lobectomy or ithsmus lobectomy. Case report: A 40-year-old female patient presented with a lump in front of her neck that was enlarging to the left since seven years ago. Physical examination showed a firm lump in the front of the neck enlarging to the left. Multiple isohyphoechoic lesions with internal calcification and inhomogeneous nodules on the isthmus were seen on left thyroid ultrasound. A CT scan revealed left thyroid enlargement with several solid masses, one of which was cystic, and calcification. Impression of a benign lesion from FNAB. Ithsmus lobectomy was performed on the left lobe. Thyroid papillary adenocarcinoma was discovered as histopathology result. Methods: Evidence search was carried out through medline, pubmed and manual searches. Result: Ithsmus lobectomy is a safe and effective treatment for benign thyroid lesions. Conclusion: A case with an initial diagnosis of benign thyroid lesions who underwent a left isthmus lobectomy and postoperative histopathological findings of papillary adenocarcinoma will be evaluated for re-assessment for thyroid malignancies.