Incidentally detected retropharyngeal cystic parathyroid adenoma in trauma imaging: A diagnostic challenge

Computed tomography (CT) is often utilized for evaluation of patients presenting with traumatic injuries, and differentiating between traumatic and non-traumatic pathologies can be difficult, particularly for uncommon or atypically presenting disease. A 43-year-old male presented to the hospital as a restrained driver in a motor vehicle collision, and CT angiogram of the neck revealed a well-defined, mixed cystic and solid lesion, with enhancing components that were initially interpreted as a retropharyngeal hematoma with contained contrast extravasation. Serial laryngoscopes revealed stability of the lesion, and the mass was resected the following day without complication. Histopathology revealed this mass to be a cystic parathyroid adenoma. Diagnosis of a functional cystic parathyroid adenoma is difficult, and an atypical presentation like in our case is challenging to the radiologist when assessing trauma CTs. The typical findings of mixed solid and cystic component, intense enhancement of the solid component, and prominent inferior polar artery should increase suspicion for a cystic parathyroid adenoma. This case emphasizes the need for radiologists to maintain a broad differential diagnosis when reviewing trauma imaging, particularly in the head-and-neck region.