Uncommon cystic presentation of a common cervical mass

Abstract

Background: Parathyroid cysts (PCs) are rare, constituting less than 0.5% of parathyroid lesions. PCs are often asymptomatic or present with non-specific symptoms, posing challenges for accurate diagnosis. Case Presentation: We report a case of a 22-year-old female presenting a painless, growing left-sided neck mass. Imaging, including contrast-enhanced neck computed tomography, magnetic resonance imaging, and high-resolution ultrasound (US), revealed a purely cystic lesion in the anterior upper mediastinum. Subsequent US-guided fine needle aspiration cytology (FNAC) confirmed the cystic nature. In situ parathyroid hormone (PTH) levels were elevated, leading to the diagnosis of a non-functioning PC. Surgical intervention was avoided, and symptomatic relief was achieved through US-guided cyst aspiration. Conclusion: This case emphasizes the rarity of non-functioning PCs and underscores the importance of a comprehensive diagnostic approach, including imaging studies and FNAC with in situ dosage of PTH levels.