A Case of Submandibular Ectopic Parathyroid Adenoma: Diagnostic Challenges and Clinical Insights

We report a case of a left submandibular ectopic parathyroid adenoma (EPA) with a tortuous diagnostic course, highlighting potential misdiagnoses and key diagnostic strategies.A 51-year-old male office worker presented with an incidentally discovered left submandibular mass persisting for 6 months and a newly detected thyroid nodule for 1 month.Initially, the submandibular mass was misdiagnosed as reactive lymphadenopathy at a local clinic, where only physical examination was performed without imaging or serological tests.Five months later, another hospital misdiagnosed the same mass as a schwannoma based on neck ultrasound (Figure 1a), during which a TI-RADS 4A nodule in the upper pole of the right thyroid was incidentally identified.Contrast-enhanced computed tomography (CT) of the neck (Figure 1b) prompted referral for surgical evaluation.