Insular Carcinoma: An Aggressive Subtype of Differentiated Thyroid Neoplasms

Nam, Seok Jin; Lee, Sang Dal; Oh, Young Ryun; Yang, Jung Hyun

Abstract

PURPOSE: Insular carcinoma is a rare subtype of thyroid cancer which is first described by Carcangiu in 1984. It is intermediate in aggressiveness between well differentiated and anaplastic thyroid carcinoma. But its origin, clinical features and prognosis are not yet clearly understood. We wanted to evaluate the clinical features, histologic characteristics and the prognosis of the insular thyroid carcinoma.
MATERIALS AND METHODS
We studied 4 cases of insular thyroid carcinoma treated in Samsung Medical Center from March 1996 to April 1998. Age, sex, clinical features, treatment, pathology and follow up findings were reviewed, retrospectively.
RESULTS
All patients were female and mean age was 44 years. Three of four patients complained anterior neck mass and one patient complained low back pain and paresthesia of right thigh. Two patients had metastatic bone lesions at the time of diagnosis. Preoperative fine needle aspiration cytology could diagnose follicular neoplasm in 2 cases and papillary carcinoma in 1. We performed total or completion thyroidectomy and radioactive iodine therapy in 3 cases and radioactive iodine therapy alone in one. Extra- thyroidal invasion, vascular invasion and multicentricity was noted in two cases. All four patients showed recurrence or distant metastasis in follow up period of 10~31 months and 2 of them died of distant metastasis.
CONCLUSION
Insular carcinoma is a special type of thyroid carcinoma with aggressive clinical course. Recurrence and extrathyroidal involvements are common and the prognosis is poorer than other well differentiated thyroid carcinoma.