Mid-facial deformity secondary to a traumatic haemorrhage in a maxillary cyst

Serious symptoms caused by intra-cystic bleeding are very rare. We describe a case of a maxillary cyst presenting with mid-facial deformity in a Japanese woman. She underwent bilateral Caldwell–Luc procedure 21 years earlier and suffered left cheek trauma 4 years earlier. She presented soon after the trauma complaining of left mid-facial deformity, and computed tomography showed a trilocular cystic lesion in the left maxilla. We performed facial osteotomy concurrent with cyst enucleation with lateral rhinotomy. Serosanguineous fluid filled the cyst cavity just below the face; however, additional cyst cavities contained straw-coloured fluid. She showed no signs of recurrence at the end of a 20-month follow-up, and her postoperative appearance was excellent. Histopathological examination showed that all cyst walls were lined by ciliated columnar epithelium, which was consistent with surgical ciliated cyst. We consider that the increased intra-cystic pressure caused by traumatic haemorrhage induced expansion of the pre-existing surgical ciliated cyst.