Intradural, extramedullary spinal sarcoidosis: report of a rare case and review of the literature.

BACKGROUND

Spinal sarcoidosis represents a rare subgroup of neurosarcoidosis. Most spinal sarcoid lesions are intramedullary, and only eight cases of intradural, extramedullary sarcoid lesions have been reported hitherto. We describe the complete entity of intradural, extramedullary spinal sarcoidosis.

METHODS

A 39-year-old woman presented with a 2-year history of slowly progressive numbness and paresthesia of the right medial upper arm followed by brachialgia and cephalgia. Magnetic resonance imaging revealed an intradural extramedullary T1 isointense and T2 hyperintense mass lesion near the right C3 nerve root exit C3, extending into the right neuroforamen. The cervical cord was not severely compressed. The mass lesion showed a high T2 signal. After intravenous administration of gadolinium-diethylenetriaminepentaacetic acid, there was marked enhancement of the process.

RESULTS

The patient underwent a C2 to C3 laminoplasty and total resection of the intradural extramedullary tumor. The lesion encroached along the right neuroforamen, involving the C3 nerve root, and was grossly adherent to some of the rootlets. Histopathological examination of the specimen showed a noncaseating granulomatosis consistent with sarcoidosis. Postoperative testing did not reveal systemic involvement of sarcoidosis but bilateral hilar and mediastinal lymphadenopathy with normal lung parenchyma. The patient was therefore treated with corticosteroids. During the follow-up period of 16 months, the patient made a satisfactory recovery, though with persistent, distally pronounced sensory disturbance in the C3 or C4 root areas, and returned to work full-time.

CONCLUSIONS

An extramedullary sarcoid lesion is rare. Unlike intramedullary sarcoid lesions, it can be totally removed. Even if systemic sarcoidosis is present, the patient can have an excellent recovery. From a review of the literature, we can hypothesize that intradural extramedullary spinal sarcoidosis may represent a very early stage of spinal sarcoidosis progressing to intramedullary intradural spinal sarcoidosis. The intradural extramedullary spinal sarcoidosis can be subdivided into a peripheral and a central subtype. Positive histological examination is required to establish the diagnosis since other diagnostic tests are unspecific.