Unresectable Ameloblastoma Successfully Treated with Definitive Proton Therapy

Abstract

We report the case of an 87-year-old man affected by an unresectable ameloblastoma of the right jaw that was successfully treated by definitive proton therapy up to a dose of 66 Gy in 33 fractions. Treatment was well tolerated, and there were no interruptions due to toxicity. At follow-up visits, the patient experienced complete response to treatment with no evidence of disease and complete recovery from acute side effects. In this report, we discuss the potential and possible pitfalls of proton therapy in the treatment of specific settings.

Keywords: ameloblastoma; head and neck cancer; paranasal sinus cancer; proton therapy.

Figure 1.

Axial, sagittal, and coronal contrast-enhanced magnetic resonance images showing ameloblastoma extension on May 2013.

Figure 2.

Typical plexiform growth of the tumor, arranged in anastomosing double columns of cuboidal cells, with minimal evidence of central stellate reticulum. Hemaoxylin and eosin stained, 200×.

Figure 3.

(A) Axial, sagittal, and coronal contrast-enhanced magnetic resonance images taken on October 2015. (B) Areas inside the red lines represent the increase in tumor extension and invasiveness compared with baseline images.

Figure 4.

A dose-volume histogram where the yellow, orange, and red isolines represent the 54, 60, and 62.7 Gy isodose lines, respectively.

Figure 5.

Comparison of a planning dose-volume histogram and a dose-volume histogram obtained from a weekly computed tomography scan showing consistency in target coverage and sparing of the organs at risk.

Figure 6.

Consolidated post–proton therapy images showing complete response taken at (A) 3 months after the end of proton therapy and (B) 1 year after the end of proton therapy.