Isolated neurosarcoidosis: case series in 2 sarcoidosis centers

Neurosarcoidosis occurs in the central or peripheral nervous system and is usually associated with other sarcoidosis organ involvement. However, when sarcoidosis develops exclusively in the nervous system, its diagnosis is problematic.

Retrospective analysis of patients who were histologically diagnosed with neurosarcoidosis without other organ involvement (isolated neurosarcoidosis) at Medical University of South Carolina and Allegheny General Hospital. For comparison, we also collected data from neurosarcoidosis patients with histologic evidence in an extraneural organ (systemic neurosarcoidosis).

Ninety-one cases of neurosarcoidosis were identified with 10 patients having isolated neurosarcoidosis. Common clinical manifestations of the isolated neurosarcoidosis patients were headache (9), paresthesia (5), and cranial neuropathies (4). All isolated neurosarcoidosis patients underwent a biopsy from the central nervous system. The prebiopsy impression included lymphoma (4), tumor (2), and sarcoidosis (2). In all patients, no extranueral sarcoidosis developed during a relatively long follow-up period (mean 58 mo). Compared with the systemic neurosarcoidosis cohort (60), isolated neurosarcoidosis patients had similar demographics and neurological manifestations with a few exceptions including a more common frequency of headache, hemiparesis, and radiculopathy, leptomeningeal involvement on brain MRI, increased cell count in cerebrospinal fluid, and a more favorable clinical outcome (P<0.05). The duration of follow-up and the number of studies performed to evaluate patients for extraneural sarcoidosis were similar in the 2 cohorts.

The clinical and radiologic features of isolated neurosarcoidosis are similar to those of systemic neurosarcoidosis with a few exceptions. The diagnosis of isolated neurosarcoidosis is problematic and often not considered before biopsy of neural tissue.