By means of histologic examination, it can be classified as uni- or multicystic. It is worth noting that the unicystic ameloblastoma behaves in a less aggressive manner than the multicystic type, and also shows a reduced potential for recurrence after treatment. Ameloblastoma occurs most often in younger patients regardless of gender or ethnicity in the posterior area of the mandible, and is commonly associated with an unerupted third molar. In this article the authors will report on the case of a year-old female Caucasian patient who presented with a radiolucent lesion in the area of an extracted molar.
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Ameloblastoma is a neoplasm usually found in the maxilla and mandible with progressive intraosseous growth and a tendency to local recurrence. Malignant or metastatic ameloblastoma is one of its rare variants; a histopathological study is required for diagnosis confirmation. The common sites of dissemination are the lungs and cervical lymph nodes. The treatment is surgical and radiotherapy or chemotherapy are palliative options.
A case of malignant ameloblastoma was reported in a year-old man with metastasis to the scalp and multiple local recurrences. The patient required mandibular osteotomy, multiple local resections, partial maxillary resection, free flap reconstruction, local scalp resection and free flap coverage. Due to a new relapse that could not be treated with a surgical approach, radiotherapy was ordered. The site most frequently affected by malignant ameloblastoma due to hematog-enous dissemination is the lung.
This paper reports the case of a patient with compromised scalp. To date, according to a search conducted, only one case report about this type of met-astatic neoplasm has been published.
Histopathological diagnosis of ameloblastoma associated with surgical resection of the primary tumor and the metastatic tumor is the only approach that can offer disease-free survival. Ameloblastoma is a rare benign intraosseous neoplasm that originates in the odontogenic epithelium. It is of unknown etiology and is characterized by expansive growth with a tendency to recurrence. The maxilla is the second most common site of presentation, while the involvement of the sinuses and nasal cavity is rare.
The clinical picture of this pathology is characterized by a mass of slow growth that is not painful at the beginning, but complications such as dental loss, dental malocclusion, paresthesia, pain, soft tissue invasion, facial deformity, limitation of mouth opening, difficulty chewing and airway obstruction can be observed as size increases. Ameloblastoma rarely evolves into malignancy and develops hematogenous spread 3 ; although the benign histology of ameloblastoma is the same, the malignant histology is characterized by the presence of metastases and is associated with cytologic atypia with or without metastases.
The current treatment is wide local excision, which should include adequate resection margins. Radiation and chemotherapy are reserved for palliative purposes only. Male patient of 39 years of age, mestizo, from Zapatoca Santander, Colombia , high school graduate, freelance trader, non-smoker, with no relevant medical history nor previous ameloblastomas or neoplastic diseases. The subject had a history of 11 years of evolution, which began with the appearance of a mass of progressive growth in the left mandibular region, associated with pain in the mandibular and dental areas with left irradiation to the mastoid.
The physical examination revealed an alteration of the facial contour due to the presence of a mass of about 7cm of anteroposterior diameter occupying the maxillary sinus and the left mandibular region. A contrasted CT scan of the neck and paranasal sinuses was performed, identifying a mass involving the left mandibular region and the pterigopalatine fossa with associated bone destruction; a biopsy with histopathological study report was also performed, showing follicular and plexiform ameloblastoma.
Taking into account the findings of the tomography and the reports from the pathologist, ameloblastoma was diagnosed without a doubt. Extension studies were also performed with chest CT and cervical lymph node puncture biopsy, ruling out distant disease. The case was discussed during a multidisciplinary meeting where a left partial mandibulectomy, mandibular condyle reconstruction with plaque and fibula free flap were established as management.
The pathology of the surgical specimen showed tumor-free edges and surgical margins of 10mm Figure 1. Source: Document obtained during the study. The patient underwent medical check-ups and contrasted sinus and chest CT every six months during the first year and then every year. After three years of follow-up, in an outpatient control consultation, the patient was found in good general condition, with adequate Weber-Fergusson's approach facial scar, left peripheral facial palsy, adequate mouth opening, island flap of the skin with vital and integrated fibula, left hemifacial induration of soft tissues and scalp lesion in left temporal region that extended to the parietal region with anteroposterior diameter of 7cm, without further pathological findings.
Biopsy was performed on the lesion of the scalp revealing ameloblastoma metastases; the subject was taken to surgery with wide local excision and free flap reconstruction. Surgical specimen pathology confirmed metastatic ameloblastoma and reported tumor-free section borders with margins of 14mm Figure 2.
The patient assisted to annual medical check-ups with contrasted CT scans; in the sixth year of follow-up, local relapse was observed, so he was taken to partial resection of the left maxilla with extension to infratemporal fossa and reconstruction with anterolateral thigh free flap. The pathology of the surgical specimen confirmed ameloblastoma and reported tumor free section borders with margins of 9mm.
Eleven years after the initial surgery, and after 3 surgeries, a new local relapse was discovered. On physical examination, the patient was found in good condition, with left facial palsy and mass in left masticator space with extension to hard and soft palate, in addition to left submandibular ganglion conglomerate. Contrasted CT showed a mass that involved the left masticator space, lobed, of heterogeneous density with extension towards the skull and average cranial fossa of The patient was assessed by a multidisciplinary team, which concluded that it was not possible to perform new surgical interventions due to the extent of the disease; instead, palliative management with intensity-modulated radiation therapy IMRT was ordered.
After simulation, planning and delimitation of the area to irradiate, a total of 66 Gray Gy in fractionation of 2 Gy was indicated, for a total of 33 sessions during 44 days. During session 12, the patient presented an episode of mucositis treated with a master formula for topical use with appropriate resolution, allowing the radiotherapy to continue without suspending it. Two months after completing the radiotherapy sessions, the patient was in good general condition but reported xerostomy; the physical examination showed clinical decrease of the mass in the masticator space and palate with changes in the left hemifacial and cervical skin secondary to radiodermatitis.
There were no clinical signs of lesion progression. Follicular cystic ameloblastoma and plexi-form ameloblastoma were identified in all the pathologies analyzed since the initial biopsy and in the different surgical specimens Figures 3 and 4 , both from the local resections and the scalp lesion.
No genetic profile of BRAFVE mutation was performed, since it was not requested during the period when the samples were processed and it is not a routine test performed in the institution. Although the surgeries performed were useful to completely resect the tumor with negative and proper surgical margins and without failures in the surgical technique or in the choice of the surgical approach, the ability of ameloblastoma to recur was demonstrated.
Ameloblastoma is a benign but aggressive intraosseous odontogenic neoplasm with progressive growth, large local expansion, bone destruction, dental resorption and a high tendency to recurrence.
Ameloblastoma presents as a slow-growing, expansive lesion, which may exhibit late, accelerated growth. Radiologically speaking, it is common to find a multilocular radiolucent image of soap bubble or honeycomb appearance in the cortex, buccal and lingual expansion, and resorption of the involved dental roots.
The diagnosis of ameloblastoma is achieved based on physical examination, including examination of the head and neck and imaging studies, which in turn include panoramic radiography, contrasted computed tomography and biopsy of the lesion. The pathological types of this disease can be varied: solid, multicystic, unicystic, desmoplastic and peripheral ameloblastoma. Since , the World Health Organization classification system made a clear distinction between ameloblastoma, malignant ameloblastoma and ameloblastic carcinoma.
A metastatic malignant ameloblastoma tumor, by definition, should have the same histological characteristics as a primary mandibular tumor. The histopathological comparison between the different surgical specimens of the reported case, which had the same characteristics between samples, was fundamental for the diagnosis of malignant ameloblastoma. Ameloblastic carcinoma combines some characteristics of ameloblastoma and cytological atypia with or without metastases.
Most ameloblastomas have predominantly follicular and acanthomatous patterns and are rarely mistaken for other lesions if adequate tissue is provided for histopathological examination. Desmoplastic ameloblastoma may cause some initial confusion, but knowing about this unusual and particular pattern that occurs in a jaw tumor should not cause diagnostic difficulties as long as adequate material is available for the pathologist to study. Since there is a time gap between the diagnosis of the primary tumor and the occurrence of metastasis, whether regional or distant 10 to 12 years on average , at least one chest x-ray per year is recommended for follow-up because it is the most frequent site of distant metastasis, in addition to clinical progression and imaging studies of the neck and primary site of surgical resection.
In the US, the annual incidence of malignant ameloblastoma and ameloblastic carcinoma is 1. The most common site of ameloblastoma metastasis is the lung The primary and optimal treatment for ameloblastoma is surgery, in other words, total excision of the lesion with radical resections and margins of 1. Treatment of metastatic lesions is not yet uniform, as sometimes surgical resection is not possible due to their anatomical location or extension; furthermore, no clear chemotherapy or radiotherapy protocols have been established for these lesions.
The effectiveness of adjuvant treatment is not clear because few cases have been described. The case reported by Jain et al. In the multivariate analysis of Yang et al. Freignani et al. The study aimed to establish predictors of recurrence, and the results suggested that the presence of a multilocular lesion with rupture of the basal cortical bone and a histological follicular tumor have poor prognosis.
The case reported here allows approaching a pathology that, although rare, has great impact on the health state of the patients who have it due to its tendency to local recurrence and distant involvement, making ameloblastoma a complex entity. For this reason, a clear, accurate and timely diagnosis of ameloblastoma, paying utmost attention to its histopathological characteristics and complete radical surgical resection with oncological resection margins, is considered as the best option for adequate survival in patients presenting with this rare entity.
Curettage of the lesion only or multiple resections due to recurrence increase the risk of metastasis. Surgery is the best alternative for the treatment of metastases; even though chemotherapy and radiotherapy have also been described, they have been recommended for palliative management. For lesions that cannot be treated surgically, radiotherapy and chemotherapy are the only options currently available; however, the recurrence rate with these techniques is high.
Here, in consequence, the treatment currently available for ameloblastoma was used, which consists of extensive surgical resection of the initial tumor, as well as of recurrent tumors and distant lesions. When new resections cannot be done, implantation of radiotherapy with IMR technique is used, which was the case of this patient. Malignant ameloblastoma is a rare entity and its timely histopathological diagnosis, associated with radical surgical resection of both the primary tumor and the metastatic tumor, is the only option that can offer disease-free survival with adequate quality of life.
Non-surgical alternatives, such as chemotherapy and radiotherapy, are only recommended as a palliative option for lesions that cannot be approached surgically or in unresectable tumor recurrence. The case of malignant ameloblastoma with scalp metastases presented here, which is one of the few reported in the medical literature, stresses the need for adequate treatment planning, timely and regular follow-up in all patients with this pathology, as well as the implementation of the genetic profile in the histopathological study, which allows predicting a more aggressive behavior of this entity.
It is worth noting that multiple surgical interventions or recurrences are a risk factor for malignant or metastatic ameloblastoma. Vered M, Muller S. Benign epitelial odontogenic tumours.
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Odontogenic tumours: a retrospective study of cases in Chinese population. Int J Oral Maxillofac Surg. Relative frecuency of central odontogenic tumors: a study of cases from Northem California and comparison to studies from others parts of the world. J Oral maxillofac Surg. Hertog D, Van der Waal I. Ameloblastoma of the jaws: a critical reappraisal base on a years single institution experience. Oral Oncol. Solid ameloblastomas.
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Recurrent Ameloblastoma: A Surgical Challenge
The authors report a patient who underwent a total of five operative interventions for recurrent lesions involving mandible and infratemporal fossa at other institutions before admission to our hospital. Gross total excision of the tumour was done and the postoperative course was uneventful. In any case with a tumour located in this region, it is important to be aware of this condition because this lesion is unusual but serious pathology as illustrated in this report. Clinically, it is painless and slow growing lesion, but behaves as invasive recurring tumours in spite of its benign histological appearance [ 1 , 2 ]. They are the most frequent odontogenic tumours of the mandible and maxilla. In this report, we present a rare case of solid and aggressive recurrent adenomatoid ameloblastoma in the infratemporal fossa extending into the maxilla.
Unicystic Mural Ameloblastoma: An Unusual Case Report
Ameloblastoma is locally aggressive benign odontogenic tumour with increased risk of recurrence rate. The choice of treatment depends on the histologic subtype. Radical therapy is the recommended modality for solid ameloblastomas. The possibilities of recurrence even after enbloc resection are still high. The author presents two case reports of recurrent ameloblastomas postradical resection.