A Rare Case of Double Pyramidal Lobe of the Thyroid Gland

Abstract

The pyramidal lobe is an anatomical component of the thyroid gland seen in up to 65% of individuals. It represents the distal, nondegenerate part of the thyroglossal duct. The double pyramidal lobe is a very rare occurrence, and this is the first reported case in Sri Lanka. A 40-year-old woman presented a long-standing goiter. Her evaluation revealed a benign multinodular goiter with a dominant right colloid nodule and background thyroiditis. She was euthyroid and had no compressive symptoms. Considering cosmesis, the patient opted for total thyroidectomy during which two pyramidal lobes were identified. The rest of the thyroid gland and the parathyroids had no anomalies. After an uneventful postoperative stay, she was discharged later. This is a very rare case where the patient had two separate pyramidal lobes; a phenomenon documented in less than 10 cases around the world. In addition to embryology, the pyramidal lobe has significance in clinical practice. It can be associated with benign and malignant disease of the thyroid; focal and diffuse. Incomplete removal may result in recurrence of the disease in the remaining thyroid tissue of the pyramidal lobe. Therefore, active inspection of the lobe including its anatomy during thyroid surgery and complete excision when indicated is of paramount importance.