Various prognoses of postoperative ameloblastoma have been reported based on type of surgery, including enucleation, curettage, and radical resection [2].
Almeida et al. [3] found that the recurrence rate after conservative treatment was 3.15 times higher than that after radical resection. According to Carlson et al. [4], conservative measures such as enucleation, enucleation and curettage, surgical excision and peripheral ostectomy, and enucleation with liquid nitrogen cryotherapy, it means an inadequate removal of tumor, but radical resection means the soft and hard tissue margins in the resection of tumor are determined to be histopathologically negative.
Regarding some patients are younger, there is a tendency towards more conservative measures for the aesthetic, functional, and psychological effects[3]. Radical resection is indicated for the solid or multicystic ameloblastoma[4, 5], these principles of radical resection will increase the likelihood of tumor-free margins in the final histopathologic sections: assessment of anatomic barriers; resection with 1 cm to 1.5 cm linear bone margins; the use of specimen radiographs and the use of frozen section.
Additionally, the initial surgical approach was correlated with the recurrence risk[6]. In our report, intraoperative frozen pathological examination was not performed during the first operation in 2006. So that the patient with simultaneous radical resection and bone reconstruction, should be performed the radical surgery to ensure that the stump of the bone is normal, and there was no tumor cell surrounding the soft tissue.Regardless of treatment method, regular follow-up is necessary after surgery. Almeida et al. [3] suggested that panoramic films should be reviewed every six months for the first five years after surgery, every year for 5–10 years after surgery, and every 2–3 years after 10 years. In our report, the follow-up of the patient was irregular and unsustainable because of the relatively low levels of dental care in China. Now the electronic medical record information in our city is gradually developing, Patients are not regularly followed-up can be reached and remaindered .
Patients with concurrent radical resection and bone reconstruction should receive regular follow-up for at least 10 years, it was the significant factor that could be helpful in early diagnosis and therapy. If recurrent ameloblastoma is suspected during re-examination, CT may be required.
According to Su et al. [7], patients with pathological diagnosis of general ameloblastoma should be provided with regular reviews for more than 10 years. But even with long-term follow-up, recurrence of ameloblastoma in situ may still occur. Therefore, pathological examinations are essential for patients under long-term clinical review, which should help improve long-term prognosis. Many factors, such as clinical type, surgical technique, number of cases, and length of follow-up, impact recurrence rates [8]. In the 2005 WHO, Ameloblastomas were classified as solid/multicystic, extraosseous/peripheral, desmoplastic and unicystic types[9]. but in 2017, the classification of ameloblastomas has been simplified and narrowed. “solid/multicystic” was dropped because it has no biologic significance, but its clinical and radiographic features sometimes was unique[1]. Records in literatures [5–8, 10–23] (table 1)among 25 patients which are about 10 patients graft bone CT showed multicystic[6–8, 12, 15, 18, 19, 21, 22]. Only 12 patients showed the pathological findings, 6 showed acanthomatous ameloblastoma[5–8, 12, 17, 18, 21, 22]. A multilocular radiographic image and follicular were presented a significantly higher number of recurrences, and it is in agreement with data reported in the international literature[24].
At present, the mechanism of recurrent ameloblastoma in grafted bone is still unclear [25]. Three possible explanations of the recurrence of ameloblastoma in grafted bone have been reported: i.e., 1) residual tumor cells in stumps; 2) residual tumor cells in soft tissues; and 3) tumor cells implanted in the bone during operation [14, 18]. According to our case, the patient’s three-dimensional CT showed that the recurrent lesions in the mandible bone were mainly invasive, i.e., the lesions invaded the grafted autogenous bone, resulting in a polycystic change. According to the clinical manifestations and auxiliary examination of the patient, A 1 cm to 1.5 cm bony linear margin and an intraoperative specimen radiograph could provide a margin-free specimen[4]. This standard of the surgery is an opportunity to assess the adequacy of the resection. Encounter the anatomic barrier of cortical bone, this should be assessed and determined preoperatively and precisely dissected intraoperatively, it depends on the experience of the surgeon. In our case, en-bloc resection and affected surrounding soft tissue maybe a cause of the second recurrence. This is consistent with the literature [6, 8, 12, 14, 15, 18, 19]. We still need to follow up patients continuously, and we look forward to more studies.