Giant Cervical Parathyroid Adenoma Mimicking a Sternocleidomastoid Mass and Presenting as a Brown Tumor of the Mandible

Abstract

A 27-year-old woman initially presented with a left mandibular swelling, and blood biochemistry consistent with primary hyperparathyroidism. On physical examination, a large left cervical mass was noted. Subsequent imaging was equivocal, as evidenced by the findings of a probable left thyroid lobe nodule on ultrasonography, increased uptake of the left sternocleidomastoid muscle region on parathyroid Tc-99m MIBI, and a normally configured thyroid on Tc-99m pertechnetate thyroid scan. The possibility of this cervical mass representing a sternocleidomastoid tumor was raised. However, a giant cervical parathyroid adenoma weighing 39.05 g was found at exploratory surgery and excised. © 2007 Lippincott Williams & Wilkins, Inc.