Surgical treatment of differentiated microcarcinomas of the thyroid.

Thyroid microcarcinomas (TMC) are histologically malignant diseases, despite their limited dimensions and non-aggressive behaviour; frequent multifocality of the disease and local recurrence is really possible after conservative resection. Modern therapeutic approaches to thyroid microcarcinoma include both radical surgical treatment, influenced by the frequent locoregional diffusion of TMC, consisting of a total thyroidectomy with an eventual central and/or functional unilateral lymphadenectomy, depending on the clinical evidence of lymh node metastases and conservative treatment based on more limited resections which take into account the slow clinical progression of this type of tumour. The aim of our work is to examine the therapeutic guidelines for surgical treatment of TMC which, in our experience, are closely dependent on clinical presentation type. From 1991 to 2000, more than 400 patients with thyroid disease were referred to the Department of Surgical Science and Applied Medical Technologies "F. Durante". Threehundred-seventythree patients received surgical treatment: in 311 patients a benign disease was diagnosed, while in 62 neoplasia was present. In total we observed 30 TMC, consisting of 28 papillary and 2 follicular microcarcinomas. On the basis of clinical presentation we divided patients in three groups: A--patients with a clinically suspicious neoplastic lesion before surgical treatment; B--patients in whom histological diagnosis of cancer was "incidental" after an operation performed for benign disease; C--patients in whom a neck lymph node metastases were clinically found before diagnosis of an "occult" papillary carcinoma in the thyroid gland. 27 total thyroidectomies and 3 conservative resections, that required successive total exeresis, were performed. In 5 cases a central neck lymph node dissection was carried out and in 5 + 1 cases functional modified lateral neck dissections was deemed necessary. Our data suggest that an evaluation of tumor's malignancy cannot be carried out on the basis of its dimensions alone. Indeed, biological aggressivity, whether local or at a distance, is a prerogative of both large and small tumours. Therefore a microcarcinoma must be considered a full-blown form of thyroid cancer and as such must be treated. Total thyroidectomy may be followed by identification of possible local metastases. "Whole body" scintigraphy allows to identify and treat with radioiodine therapy, possible recurrent lesions. Therefore in conclusion, total resection is not only a useful, but also a necessary treatment for the correct diagnostic and therapeutic follow-up of these patients.