Chondroblastoma of the apex portion of petrousal bone.

Background: Skull chondroblastoma is extremely rare. We described in this study the first case of petrousal bone apex chondroblastoma.

Methods: The tumor occurred in a 12-year-old girl and was revealed by left hypoacusis, vertigo, and walking instability. Computerized tomography scan depicted well-demarcated and osteolytic lesion of the left petrousal bone just before the internal acoustic meatus. The tumor was operated on by a subtemporal approach with a subtotal resection. Lesion recurred and was operated a second time by a combined approach subtemporal and translabyrinthine. This treatment was completed by radiotherapy. We used a combination of photon therapy and proton therapy. Outcome was good and free of recurrence 36 months after the second operation.

Conclusion: Proton therapy can be particularly useful for skull base tumors frequently radioresistant and near very important structures. This case is the first one of a successful treatment by proton therapy for chondroblastoma recurrence.