A case of venous malformation in the pterygomandibular space

We report a case of a venous malformation in the pterygomandibular space that could not be diagnosed by various preoperative examinations.A 57-year-old female patient underwent a panoramic X-ray examination at another hospital for an impacted right mandibular wisdom tooth, which revealed a radiolucent area in the right mandibular ramus.The patient was referred to our hospital for further examination and treatment of the lesion.Panoramic X-ray findings showed a clearly demarcated radiolucent area extending from the right mandibular foramen to the mandibular notch.CT findings revealed a clearly demarcated 25 20 mm tumor within a concavity of bone in the same area.MRI findings showed the lesion to exhibit slight hypointensity on T1-weighted images and marked hyperintensity on T2-weighted images.Based on these findings, a schwannoma was suspected, and the lesion was excised intraorally under general anesthesia.Tumor encapsulation was observed: it was removed en bloc without adhesion to the inferior alveolar nerve or medial pterygoid muscle.No obvious feeding vessels were observed leading into the tumor.The excised lesion was histopathologically diagnosed as a venous malformation.The postoperative course was uneventful, and no recurrence has been observed after seven years.