Chondroid lesions of the parotid gland are exceptionally rare. The differential diagnosis includes pleomorphic adenoma with extensive chondroid differentiation and extraskeletal chondromas. Clinically, they present as slow-growing, painless, well-circumscribed masses. A 70-year-old asymptomatic male was referred after incidental detection of a parapharyngeal mass on brain MRI. Clinical and endoscopic evaluation revealed left oropharyngeal and nasopharyngeal bulging. Neck MRI showed a well-defined, predominantly cystic lesion in the deep lobe of the left parotid gland, with peripheral nodularity, high T2 signal, high apparent diffusion coefficient (ADC 1 ) values, and minimal enhancement. Following ultrasound guided fine needle aspiration (FNA 2 ) pleomorphic adenoma was considered. The patient underwent partial parotidectomy and histopathology showed a chondroid lesion with degenerative changes. RNA sequencing revealed a HMGA2::WIF1 fusion. The tumor was completely excised with close margins. Postoperative recovery was uneventful. The presence of an HMGA2::WIF1 fusion favors a diagnosis of chondroid pleomorphic adenoma rather than a true extraskeletal chondroma, although a true chondroma cannot be fully excluded. Complete surgical excision with preservation of the facial nerve is the standard treatment. Recurrence remains a consideration; therefore annual imaging follow-up can be considered, taking into account tumor characteristics and surgical factors. Chondroid lesions of the parotid gland are rare and diagnostically challenging. The identification of an HMGA2::WIF1 fusion, characteristic of pleomorphic adenoma but not reported in chondromas, supports classification as a chondroid pleomorphic adenoma. These findings question whether salivary gland chondromas constitute a distinct entity and highlight the value of molecular analysis in this differential diagnosis.
Ramírez et al. (Sun,) studied this question.