The Pyramidal Lobe of the Thyroid

Anatomy of the thyroid has been extensively studied but the presence of pyramidal lobe varies in percentages from 15% to 75% of cases according to different authors. We therefore investigated systematically this peculiar anatomical aspect. From January 2001 to December 2011, 1002 patients underwent total thyroidectomy in our Division of General Surgery. We analyzed the data collected on the latest 200 thyroidectomies: for all patients pyramidal lobe was measured at removal of the specimen then dimension of the pyramidal lobe after fixation was checked. We found the pyramidal lobe in all cases. In most cases, it was approximately 2 cm (range 1 - 8 cm on fresh specimen). At histology it was described in 72% of cases, after fixation size decreased by a third approximatively. This is the first systematic intraoperative study to verify the prevalence of the thyroid pyramidal lobe. In our experience, the pyramidal lobe is always present and the thyroglossal duct is identifiable.