The forgotten lobe in focus: a rare case of isolated pyramidal lobe papillary thyroid carcinoma

Isolated papillary thyroid carcinoma (PTC) arising from the pyramidal lobe (PL) is an uncommon entity that may clinically present as a midline neck swelling, often mimicking a thyroglossal duct cyst and thyroglossal duct cyst carcinoma.

A 46-year-old woman presented to the clinic with a solitary, midline neck swelling that was firm and mobile. The patient underwent relevant investigations, and the diagnosis was confirmed to be isolated PTC of the PL. The patient underwent total thyroidectomy and had an uneventful recovery without residual or metastatic disease.

Isolated PL PTC poses a diagnostic challenge due to its clinical and radiological resemblance to thyroglossal duct cyst carcinoma and Delphian node metastasis. Failure to recognize this entity may lead to inadequate surgical management. Given its reported association with extrathyroidal extension, multifocality, vascular invasion, and a possibly aggressive molecular profile, comprehensive surgical evaluation, including total thyroidectomy, should be considered to reduce recurrence risk and facilitate postoperative surveillance.

A high index of suspicion, detailed imaging of the midline neck structures, and awareness of embryological variants are essential to avoid misdiagnosis and ensure optimal oncological treatment in cases of PTC of the PL.