Multifocality of thyroid carcinomas: a "privilege" of papillary tumors or not?

To study the frequency of multifocality in well-differentiated non-medullary thyroid carcinomas and correlate it with various epidemiological factors, as well as with patients' survival.

A retrospective study was conducted on 80 patients who underwent total thyroidectomy from January 1985 to December 2004 in the First Department of Surgery of University General Hospital of Alexandroupolis, Democritus University of Thrace, Greece, for well-differentiated non-medullary thyroid cancer (papillary and follicular). Patients' medical records and demographics, including age, gender, histological type (papillary, follicular), multiple foci of tumors, overall and specific survival were analyzed.

Multifocality was established in 17/80 patients (21,25%). Multifocal tumors were found in 4/20 male patients (20%) and 13/60 female ones (21,67%), percentages which are almost identical. Increased rates of multifocal tumors were found in the age groups of 20-29, 30-39 and 70-79 years old, while low rates were documented in the age groups of 0-9, 10-19 and 60-69 years old. Follicular tumors had a 20% rate, similar to papillary tumors (22,2%), and an impressive multifocal rate of mixed papillary-follicular neoplasms (75%) was found. Finally, survival was not found to be influenced by the multifocality of the tumor, under the prerequisition that total thyroidectomy is applied.

Multifocality should not be considered as a "privilege" of papillary thyroid tumors, but as a privilege of thyroid carcinomas in general. If total thyroidectomy is applied in all benign and malignant thyroid diseases, the presence of multiple foci does not affect the prognosis and the survival of the patients.