The clonality of nodules in recurrent goiters at second surgery

Introduction: Some studies showed that in multinodular goiters clonal and polyclonal nodules coexist. The clonality of nodules in recurrent goiters is, however, still unknown and may contribute to help explain the pathogenesis of this thyroid disease. Methods and results: The clonality of 14 nodules derived from recurrent goiters was assessed by means of an X-chromosome-inactivation method. Of 14 nodules, 10 showed a polyclonal pattern, 3 were clonal and, in 1 case, the result remained unclear. The mean age of the patients with recurrent goiter at the time of their first operation was significantly lower than the mean age of 50 patients who underwent thyroid surgery for the first time over the same period of time (34.6+/-10.9 years vs 53.7+/-13.5 years; P<0.05). The mean interval between first and second operation was 18 years. Conclusion: The finding that nodules in recurrent goiters are predominantly polyclonal suggests that these lesions have their origin in a de novo proliferation of different cohorts of thyrocytes due to unknown growth stimulating molecular events.