Tumefactive brain parenchymal neurosarcoidosis

Background: Enhancing brain parenchymal disease, and especially tumefactive lesions, are an uncommon manifestation of neurosarcoidosis. Little is known about the clinical features of tumefactive lesions and their impact on management and outcomes, which this study aims to characterize.

Methods: Patients with pathologically-confirmed sarcoidosis were retrospectively reviewed and included if brain lesions were: (1) intraparenchymal, (2) larger than 1 cm in diameter, and (3) associated with edema and/or mass effect.

Results: Nine patients (9/214, 4.2%) were included. Median onset age was 37 years. Diagnosis was confirmed by brain parenchymal biopsies in 5 (55.6%). Median modified Rankin scale (mRS) score was 2 (range 1-4) at initial presentation. Common manifestations included headache (77.8%), cognitive dysfunction (66.7%), and seizures (44.4%). Sixteen lesions were present in 9 patients. The frontal lobe (31.3%) was most affected, followed by the subinsular region (12.5%), basal ganglia (12.5%%), cerebellum (12.5%), and pons (12.5%). MRI characteristics of the dominant lesions included spherical morphology (77.8%), perilesional edema (100.0%), mass effect (55.6%), well-demarcated borders (66.7%), and contrast enhancement (100.0%; 55.6% heterogeneous). Leptomeningitis was frequently present (77.8%). All required corticosteroid-sparing treatments, and most (55.6%) needed at least a third line of treatment (infliximab used in 44.4%). All patients relapsed (median 3 relapses, range 1-9). Median last mRS was 1.0 after median follow-up of 86 months, with significant residual deficits in 55.6%.

Conclusion: Tumefactive brain parenchymal lesions are uncommon, usually affect the supratentorial brain along with leptomeningitis, and are refractory to initial treatments with a high risk of relapse. Significant sequelae were encountered despite a favorable median last mRS.