Invasive Tall Cell Variant of Papillary Cancer originating from the Pyramidal Lobe of the Thyroid Gland

A pyramidal lobe of the thyroid gland is a common anatomic variant. However, primary malignancy of the pyramidal lobe is rare with the exception of cancer in a thyroglossal duct cyst. A 61-year-old morbidly obese woman presented with a 30 lb. weight loss and a large asymptomatic submental neck mass that extended to the base of her tongue. The mass was invading the hyoid bone and the sternohyoid muscles. The patient had a short thick neck and “double chin,” which lead to delay in recognition of the neck mass. Further workup and final pathology revealed a locally invasive, tall cell variant of papillary cancer arising from the pyramidal lobe of the thyroid gland with regional and systemic metastases. To our knowledge, this is only the second case of a thyroid cancer arising from a pyramidal lobe reported in the literature. Primary thyroid cancer arising from the pyramidal lobe should be considered in the differential diagnosis of a midline neck mass.