Malignant ameloblastoma

Radiotherapy in the treatment of ameloblastoma

There is a lack of well-documented evidence in the literature concerning the relative radioresponsiveness or radioresistance of ameloblastomas, although they are generally considered radioresistant. Most of the previous papers referring to this subject lack acceptable histopathologic proof of the diagnosis, adequate radiotherapeutic data, and/or follow-up information; many predate the use of megavoltage irradiation. The present article reports 5 cases of ameloblastoma that were treated by radiotherapy, 3 by megavoltage irradiation. All have been confirmed histologically by an oral pathologist, all have adequate radiotherapeutic data and, with one exception, adequate follow-up information. In addition, the reasons for our present lack of knowledge of this subject are discussed; objective criteria are presented for evaluating the results of radiotherapy on ameloblastomas; the only other series of ameloblastomas treated by megavoltage irradiation is analyzed. Although radiotherapy can reduce the size of an ameloblastoma, primarily that part of the tumor which has expanded the jaw or broken into the soft tissues, it does not appear to be an appropriate treatment for an operable ameloblastoma. Its main use is in inoperable cases, primarily in the posterior maxilla.

Distant skin metastases in a long-term survivor of malignant ameloblastoma

We report a case of distant cutaneous metastases in a 68-year-old patient with malignant ameloblastoma of the mandible. The metastatic lesions were first noted approximately 31 years after resection of the primary tumor. Metastases to lung, pleura, bone, and brain had also occurred. Histochemical findings differ from those described in adamantinoid basal cell carcinoma. Cutaneous metastasis probably resulted from hematogenous dissemination. To our knowledge, this is the first report of such an occurrence in English language literature.

Ameloblastoma of the jaw. A reappraisal of the role of megavoltage irradiation

Ten patients with ameloblastoma of the jaw were treated with megavoltage irradiation between 1958 and 1982. Seven cases were treated with radiation alone and six responded initially. One patient subsequently recurred and was successfully salvaged surgically. Three patients were treated with combined radiation therapy and surgery. Carefully applied megavoltage irradiation has a useful role in the management of ameloblastoma, particularly in large maxillary tumors with associated destruction of the infrastructure of the maxillary antrum. It is apparent from this series, and from the literature, that the ameloblastoma is not an inherently radioresistant tumor.

Treatment of the ameloblastoma: a controversy

Treatment of the ameloblastoma should be re-evaluated based on microscopic behavior. We suggest that conservative therapy is the initial treatment of choice. Although medullary bone is invaded by tumor cells, compact bone only is eroded. Therefore, treatment should be directed at removal of involved medullary bone, leaving as much medial and lateral cortical plates and inferior mandibular border as possible. Four patients with ameloblastoma treated conservatively are presented. Evaluation from 21 months to seven years after initial therapy revealed marked bone regeneration. Three of the four had smaller lesions remaining, requiring less radical surgery than would normally have been performed initially. No tumor was evident on rebiopsy of the fourth patient. Conservative treatment and proper follow-up were acceptable methods of initial treatment in our cases.

Reconstruction of the defective mandible

In a clinical material consisting of 31 cases of mandibular defects, caused by tumour resection or by trauma, reconstruction has been carried out by means of a stabilizing titanium splint and autologous bone and marrow transplantation, the longest period of observation being 9 years. The functional results obtained are assessed with reference to the cause of resection. Different technical procedures are described and the objectives and the planning of reconstruction of the lower jaw are discussed.