Operative indications of follicular type tumors,based on Japanese clinical guidelines

AIM: To investigate the accuracy of preoperative examinations in follicular type tumors, we re-evaluate results of our operative cases.METHODS: Cases are follicular neoplasms in 36 patients, which are more than 30 mm in diameter and underwent surgery in our hospital in 2005-2006. These cases had been suspected of malignancy on one or more of the preoperative examinations, including ultrasound(US), thallium-technecium(Tl-Tc) scinitigram,computed tomography(CT), or fine needle aspiration biopsy(FNA) examinations. Concern about operative procedure, lobectomy plus sentinel lymph node biopsy(SNB) was performed in all 36 follicular tumors at the first surgery. Because we can diagnose a suspected follicular tumor as carcinoma and can change the operative procedure intra-operatively, when the metastasis of lymph nodes, outside of the thyroid, is found. The operative procedure was changed from lobectomy to total thyroidectomy plus lymph nodes dissection(centralcomponent), when the SNB has metastasis. All thirty six cases were obtained to track the prognosis until 2012, for 6-7 years follow up periods.RESULTS: The final pathological results are 3 cases of follicular carcinoma, 6 cases of papillary carcinoma, 1 case of papillary carcinoma follicular type, 1 case of malignant lymphoma, 16 cases of follicular adenoma, and 9 cases of adenomatous goiter. The malignant tumor were observed in 11/36(30.6%) cases. All six papillary carcinomas were less than 20 mm, and present with follicular adenoma and adenomatous goiter, which have more than 40 mm diameter. In physical examination, tumor size of 36 cases of follicular neoplasm is more than 30 mm all at the time of surgery. The tumors were palpable somewhat stiff, such as no cystic component in 34 cases. Occasional dyspnea, dysphagia, and cough was accompanied in all 36 cases. The true ratio of correct diagnosis of preoperative US, Tl-Tc scinitigram, CT, and FNA were 17/36(47.2%), 16/36(44.4%), 24/36(66.7%), 21/36(58.3%), respectively. In 11 malignant cases, there was one SNB positive case(one lymph node metastasis in 3 SNB: 1/3). This case was changed the operative procedure from lobectomy to total thyroidectomy plus lymph node dissection(central component). There is other lymph nodes metastasis in dissected lymph nodes(4/15). For the remaining malignant 10 cases, the observations were selected without additional resection, because surgical margins and SN were negative in postoperative pathology results at the first operation. No recurrence and metastasis are allowed in 11 malignant cases, up to 7 years after post-operation. Over all, the more than 30 mm in diameter follicular neoplasms, which were suspected the malignancy in the one and more preoperative examinations, are present the malignancy by pathological diagnosis in 11/36(30.6%) cases after surgery. The non SNB metastasis cases had no symptoms of lymph nodes metastasis up to 7 years after post-operation.CONCLUSION: We think that more than 30 mm in diameter follicular neoplasms are considered as candidates of surgery from our results.