Preoperative Diagnosis of an Extradural Cyst Arising from a Spinal Facet Joint: Case Report

Synovial cysts of the cervicothoracic junction causing myelopathy: report of 3 cases and review of the literature

Synovial cysts are uncommon pathological entities in patients with cervical degenerative spinal disease, and there are only a few reports in the literature. Treatment typically involves decompression; however, biomechanical data indicate that laminectomies in the cervical spine also result in cervical instability, specifically within the cervicothoracic junction, supporting the use of fusion as well. The authors describe the use of fusion with decompression in the treatment of 3 patients with cervicothoracic synovial cysts that presented in an acute fashion with associated myelopathy and neurological decline, and they review the diagnostic elements, histopathology, and treatment of these cysts. All 3 of the patients did well with decompression via a posterior approach with a single-level instrumented fusion from C-7 to T-1. Each patient regained complete neurological function and had no residual neurological deficits. These results are promising, although the sample size of 3 cases is too small to make any conclusive evaluations. Future studies incorporating Class I and Class II data are imperative to make firm conclusions regarding general management of this rare entity.

Isolated unilateral hypoglossal nerve palsy secondary to an atlantooccipital joint juxtafacet synovial cyst

Juxtafacet cysts of the atlantooccipital joint that present with isolated hypoglossal nerve palsy are rare and may mimic more common pathological entities. The authors report on the third such case in the literature and discuss the differential diagnosis, imaging hallmarks, preoperative recognition, and surgical management of this lesion, and provide a review of the literature.

The authors discuss their experience with the treatment of a 67-year-old woman who presented with an isolated hypoglossal nerve palsy caused by a nonenhancing cystic septated lesion abutting the lateral medulla just medial to the left hypoglossal canal. The lesion was presumed to be a necrotic hypoglossal schwannoma or epidermoid tumor. Intradural surgical exploration failed to demonstrate an intradural lesion, but confirmed the presence of an extradural mass caudal to the hypoglossal nerve. Extradural exploration revealed a synovial cyst of the atlantooccipital joint, which was then resected. Postoperatively, the patient developed worsening dysphagia and hoarseness. Failure to recognize this rare entity preoperatively resulted in unnecessary intradural exploration and cranial nerve morbidity. In retrospect, the preoperative diagnosis of this lesion was suggested by lack of central enhancement, absence of dumbbell formation and the presence of erosive synovial changes. Regardless, the extreme rarity of this lesion at this location will always make its recognition challenging.