Chondromyxoid Fibroma of the Skull Base: Our Experience with an Elusive Disease

Chondromyxoid fibroma (CMF) is an extremely rare lesion of the skull base. This histologic type typically predilects metaphysis of the long bones. It is locally invasive/infiltrative, and this tendency is more concerning in the skull base, where a radical resection is often technically impossible because of the presence of vital neurovascular structures. We present a case of a 19-year-old woman who presented with a sudden onset of right facial weakness, progressively worsening to a severe disfiguring motor weakness. Gadolinium-enhanced brain magnetic resonance imaging showed an osteolytic lesion located in the right mastoid involving the stylomastoid foramen and the right seventh cranial nerve. A partial mastoidectomy was performed, with an excellent rate of tumor resection and complete local control of the disease at follow-up. The analysis of current literature indicates that a radiologic diagnosis is rarely strictly convincing of CMF. Histologic diagnosis is often difficult due to the lack of a specific immunohistochemical pattern of chondrosarcoma. Surgery is currently recognized as the mainstay to manage this lesion, although a trend toward adjuvant radiation therapy (RT) currently is seen. Although a tendency of local recurrence is well recognized in the literature, the very slow and indolent behavior of this lesion plus the trend to enhance local control of the disease with high-dose RT pushed us to a reappraise the role of radical skull base surgeries burdened by the risks of major complications, cosmetic deformities, and additional neurologic deficits.