Sarcoidosis presenting as "corset-like" myelopathy: a description of six cases and literature review.

Sarcoidosis of the spinal cord is rare, even more so as the initial presentation of the disease. We describe six cases of spinal cord sarcoidosis and delineate a distinguishing feature which may allow for a timely diagnosis. All patients were admitted with complaints of a "corset-like" pressure in the lower chest and later developed cranial nerve palsies (two patients), parasthesias/paraparesis (two patients), fever of unknown origin (one patient), and bilateral proptosis (one patient). Serological tests, immunological screening, cerebrospinal fluid (CSF) analysis, bacteriological and viral testing were performed in all patients. Spinal and cerebral MRI, high-resolution computed tomography (HRCT) of the chest and gallium scan suggested the diagnosis of neurosarcoidosis of the spine while a biopsy of mediastinal lymph nodes, extra-ocular muscles, or spinal cord confirmed it. CSF showed inflammatory signs in 66% of patients and serum ACE levels were increased in a similar fraction. MRI revealed a gadolinium-enhanced thickening of the cord at the thoracic level in three patients whereas three other patients had normal spinal MRI despite similar symptoms. The presence of mediastinal lymphadenopathy on HRCT of the chest suggested the diagnosis in a third of patients. Patients were treated with steroid, immunosuppressive therapy and/or biologic therapies, with complete resolution in one case, improvement in four, and a somewhat deteriorating course, with development of spinal cord atrophy in the final case. As spinal cord involvement of sarcoidosis is extremely rare, making the diagnosis in the absence of systemic disease is challenging. The cases herein described suggest that sensory disturbance in a "corset-like" distribution may be indicative of neurosarcoidosis, especially when accompanied by extra-axial involvement such as cranial nerve palsies. This should prompt an evaluation for systemic involvement, keeping in mind that serum ACE and chest radiographs may be normal in the presence of primarily CNS-limited disease.