Incidental papillary carcinoma in patients treated surgically for benign thyroid diseases

The frequency of incidental papillary carcinoma (IPC) has been reported to be between 4.6 % and 10% in operatively treated benign thyroid diseases. This study reviews the occurrence of IPC in thyroid glands removed for benign disease at our institution.

Six hundred and seventy-eight patients underwent partial or total thyroidectomy for benign thyroid diseases. The incidence of IPC was compared among patients with Hashimoto's thyroiditis, multinodular goiter, follicular adenoma, and Graves' disease.

Overall, 81 (12.0%) IPCs were recorded with decreasing order of frequency: Hashimoto's thyroiditis, follicular adenoma, goiter, and Graves' disease. Contralateral IPC was detected in 6/15 (40%) patients with follicular adenoma.

The overall incidence of IPC in benign operatively resected thyroid disease was 12%. Hashimoto's thyroiditis had the greatest rate of IPC. IPC was encountered in the contralateral lobe in 40% of patients with follicular adenoma. The association of IPCs with Hashimoto's thyroiditis may indicate a link to thyroid cancer. Total thyroidectomy may be considered an appropriate operative treatment in patients with Hashimoto's thyroiditis and follicular adenoma requiring operation owing to the high incidence and frequent contralateral involvement of IPC, respectively.