Background Insular carcinoma of thyroid (ICT) is a rare malignant tumor with poor differentiation of the thyroid , most patients are middle-aged and elderly women. Here is a report of a case involving a young woman suffering from insular thyroid carcinoma.Case report This report is about a 23-year-old young mother who already has three children of hers. she accidentally discovered a left neck mass with slight pain from local compression about half a year ago and did not seek medical treatment. She came to the hospital this time because the neck mass recently increased rapidly and she felt pressure on the trachea, affecting swallowing. Ultrasonography showed that the maximum diameter of the hypoechoic nodules was 61*46mm in the left and no lymph nodes enlargement were seen on both sides.The patient had a partial left thyroidectomy and histopathological results revealed ICT. Therefore, she completed total thyroidectomy and cervical lymph node dissection. The postoperative process was relatively smooth and the patient was successfully discharged.Conclusion：Not all patients with insular thyroid carcinoma have similar imaging findings, so Fine Needle Aspiration Cytology(FNAC)pathological diagnosis is necessary before surgery.