Chondromyxoid Fibroma With Secondary Aneurysmal Bone Cyst in the Cervical Spine * CASE REPORT

This case report describes a rare bony cervical tumor, chondromyxoid fibroma (CMF) which has features of an aneurysmal bone cyst (ABC). The true etiology of CMF and ABC is unknown. The aneurismal bone cyst may be the result of a specific pathophysiologic change, which is probably the result of trauma or a tumor-induced anomalous vascular process. In approximately one third of cases, the preexisting lesion can be clearly identified. The most common of these is the giant cell tumor, which accounts for 19-39% of cases in which the preceding lesion is found. Other common precursor lesions include osteoblastoma, angioma, and chondroblastoma. Less common lesions include fibrous dysplasia, fibroxanthoma (nonossifying fibroma), chondromyxoid fibroma, solitary bone cyst, fibrous histiocytoma, eosinophilic granuloma, and even osteosarcoma. The treatment of the secondary ABC is based on the appropriate treatment for the underlying tumor. Complete local excision with tumor-free margins avoids the recurrence of CMF, the underlying tumor in this case report. M.I. was a 27-year-old female administrative assistant. Her chief complaint was of right-sided neck pain with numbness and paresthesias radiating into the right upper extremity, gradually worsening over the preceding six months. The sensory abnormalities began proximally in the right shoulder and progressed to involve the right lateral arm, radial forearm, and eventually the thumb and index finger. She had sustained no memorable injury and her symptoms had failed to improve with non-steroidal anti-inflammatory agents (NSAIDs) and physical therapy. She described her neck pain as moderately severe (pain score of 4 on a visual analog scale of 0–10). The family history was significant for a malignant brain neoplasm, but the patient had an unremarkable medical history and review of systems. Physical examination demonstrated no evidence of paraspinous muscular spasm or tenderness to palpation. Her cervical range of motion was normal and painless. Spurling’s sign was positive on the right side. Axial compression and facet loading caused no pain. Motor examination was intact. Sensory examination was intact to both light touch and pinprick. Reflexes were brisk 31 and symmetric in both the upper and lower extremities. Tinel’s sign and Phalen’s sign were negative at both the wrist and elbow. Imaging studies demonstrated an obvious abnormality. A lateral cervical radiograph demonstrated lucency in the base of the C6 spinous process (Figure 1). T2weighted sagittal magnetic resonance imaging (MRI) showed lamina and right lateral mass of C6 extending into the neural foramen (Figure 2). T1-weighted axial MRI with gadolinium showed a homogenous pattern of enhancement in the C6 lamina and right lateral mass (Figure 3).