[Aneurysmal bone cyst of C5. Complete 2-stage excision].

A case of aneurysmal bone cyst of the fifth cervical vertebra was unusual in that it occurred in a 35 year old man treated initially by radiotherapy (3,800 rads), within 3 years, worsening of clinical and radiologic signs led to a complete two-stage exeresis because of extension of lesion to body and posterior arch of C5. This male patient was 35 years old at diagnosis and 38 at time of surgery (respectively 1.2 and 2.5% of cases in the Hay series and 1.9% in the Ruiter series), this lesion affecting mainly age groups under 20 years. Aneurysmal bone cyst (ABC) constitutes 1.4% of primary bone tumors (Dahlin), and spinal localizations 3% (Biesecker), 14% (Reiter) or 20% (Tillman) of total ABC. The cervical lesion represents 13% (Reiter) or 22% (Hay) of spinal localizations, C5 being affected twice in the 17 cases reported by Ameli, and fills, according to Hay, 3.3% of all spinal column lesions and 15% of cervical lesions. Initial treatment applied in another center was by radiotherapy alone at the dose of 3,800 rads (the recommended dose-level in the literature being 20 to 30 Grays). Neither clinical nor radiologic improvement was reported. The recurrence rate after all types of treatment for ABC was 12.6%, and after radiotherapy alone was 11% in the Hay series, MacCarty reporting only one recurrence among 9 patients treated with irradiation alone.(ABSTRACT TRUNCATED AT 250 WORDS)