A Case of Neurosarcoidosis Mimicking Brain Tumor

Neurosarcoidosis manifests symptomatically in 5% of patients with sarcoidosis and diagnosis can be challenging if not clinically suspected. Cerebral mass-like presentation of neurosarcoidosis rarely reported in the literature. We presented a woman with neurosarcoidosis who had a cerebral mass-like lesion which completely disappeared after medical treatment.

A 37-year-old woman with history of pulmonary sarcoidosis referred to the emergency service of our hospital with a one-month history of progressive dizziness, nausea and seeing flashing lights. At neurologic examination, numbness and weakness on the left side of the body, deviation of uvula toward the right side was seen. Cranial MRI demonstrated a 2.5x2 cm in size mass lesion which hypointense on T1 WI, heterogeneous hyperintense on T2 and FLAIR sequence with peripheral vasogenic edema and heterogeneous, irregular contrast enhancement simulating brain tumor. Also, leptomeningeal and nodular contrast enhancement was seen on brainstem, cerebellar vermis, perimesencephalic cistern and left frontal, bilateral parietooccipital sulcus. In laboratory tests; The level of serum angiotensin-converting enzyme (ACE) was 53 IU/mL (N:8-52 IU/mL) and cerebrospinal fluid (CSF) ACE was 23 IU/mL (N:0-2.6 IU/mL). CSF cytology analysis was normal. Pattern 2 oligoclonal bands were present. With these clinical, laboratory and radiological findings, cerebral involvement of sarcoidosis was suspected. Biopsy was not performed due to the high risk of morbidity caused by the deep location of the lesion.Patient was treated with methylprednisolone and Azathioprine for a month.On post-treatment control imaging; lesion disappeared completely without residual leptomeningeal and nodular contrast enhancement.Also, neurologic symptoms were decreased remarkably.

Multi-system inflammatory disorders like sarcoidosis, can present with mass-like lesion in the brain parenchyma. While early diagnosis is important to prevent unnecessary interventions like biopsy and surgery, it is crucial to initiate the necessary treatment with the aim of recovery without sequelae. Radiological and clinical follow-up are fundamental in differential diagnosis.