Cystadenoma is a benign tumor derived from glandular tissue characterized by glandularly growing epithelium forming numerous large cysts. Cystadenoma originating from the retromolar region are extremely rare. We report a case of a giant cystadenoma extending from the retromolar region to the parapharyngeal space.
The patient was a 64-year-old female. She had noticed swelling in her right mandibular molar region for a year, and visited our department because the swelling was growing gradually. At her first visit, the mucosa of the pharynx was markedly swollen from the posterior part of her right mandibular acetabulum to the oropharyngeal isthmus. The surface of the swelling was smooth and there was no pain, neuropathy, trismus, dyspnea or dysphagia observed. Contrast-enhanced MRI revealed a 40×30×23 mm well-defined mass with multiple cyst formations from the posterior part of the right retromolar region to the parapharyngeal space. A tissue biopsy showed no evidence of malignant tumor; however, it was difficult to determine the histology. We suspected a benign salivary gland tumor and performed surgery under general a nesthesia. The tumor was enucleated as a single mass using the mandibular midline transection method. Histopathological examination revealed large and small cysts lined with epithelial cells with acidophilic columnar and cubic structures, and minor salivary gland tissue was found on the surface of the tumor, so we diagnosed cystadenoma. There has been no tumor recurrence five years after the operation, and the patient is doing well.
