We report a case of a cyst similar in characteristics to postoperative maxillary cysts which do not require surgical care such as maxillary sinus radical operation and trauma. The patient was a 57-year-old woman in whom spontaneous pain and swelling of the left gena and left maxillary gingival occurred. Left-sided maxillary sinusitis was suspected, so cyst enucleation was performed under general anesthesia with the diagnosis of upper jaw cyst in the left side. The cyst wall consisted of fibrous connective tissue. On the surface of the connective tissue, a hyalinized band-like structure was seen. The surface opposite to the cyst inner surface was partly covered by respiratory epithelium and squamous epithelium, and was found to be similar in appearance to a postoperative maxillary cyst and surgical ciliated cyst.