Synchronous occurrence of ipsilateral synovial chondromatosis of the temporomandibular joint and pleomorphic adenoma of the parotid gland☆

We present a unique case characterized by true coexistence of synovial chondromatosis (SC) of the temporomandibular joint (TMJ) with a salivary gland tumor, specifically pleomorphic adenoma, of the ipsilateral parotid gland. The possibility that the condition was the result of a single pathologic entity, ie, SC with extracapsular involvement or pleomorhic adenoma affecting the TMJ, received strong consideration. Nonetheless, careful assessment of the clinical, radiographic, MRI, and surgical findings strongly suggested the synchronous occurrence of 2 separate pathologic processes, despite their close proximity. Further, histopathologic examination confirmed the presence of both SC of the TMJ and pleomorphic adenoma of the superficial lobe of the ipsilateral parotid gland. Previous reports have pointed out the possibility of misdiagnosing extracapsular spread of SC as a salivary gland tumor. Vice versa, it has been noted that parotid gland tumors, especially malignant, may cause TMJ symptoms similar to those of SC. However, to the best of our knowledge, this is the first time that true synchronous occurrence of ipsilateral SC and pleomorphic adenoma, or parotid tumor of any kind, is reported.