The pyramidal lobe: a scintigraphic assessment.

The thyroid scintigraphs of 207 patients were examined with a view to investigate the anatomical origin of the pyramidal lobe (PL) and in order to determine the incidence of its scintigraphic detection. The PL was visualized in 41% of the cases studied with a greater incidence among the females as compared to the males. It was established that the likelihood of the PL arising from the isthmus of the thyroid or its lobes was about the same. Further, it was observed that the isthmal PL was usually located in the mid-line rather than laterally, in which case it was more often deviated to the left than to the right. The scintigraphic visualization of the PL was seen to increase with the size of the gland but in large goitres it was difficult to detect. It evolves that although at times, there might be a discrepancy between the apparent and the actual location of the PL due to the presence of overlying tissue, in a majority of cases, the scintigraphic appearances do in fact reflect the true picture.