Clinical History: 28 year old black male. Chief complaints were lethargy and hallucinations, both visual and auditory. Progressive behavioral decline over two years began with headaches and lead to complete disorientation in combination with diplopia and staggered gait.
Diagnosis: Neurosarcoid
Discussion: This is an idiopathic, chronic, immune related, typically multisystem diagnosis of exclusion. The disease affects the CNS in upto 5% of cases. Only 2.5% of the time is the disease isolated to CNS. Cranial nerve palsies are typical clinical manifestations of such involvement. Seizures are less common. Neuroradiologic findings typically include focal or diffuse meningeal enhancement and thickening, classically basilar. Less common findings include hypothalamic, infundibular and intraparenchymal granulomatous mass changes. Associated hydrocephalus can occur. Differential considerations include tuberculosis, other infectious meningitides, and meningeal carcinomatosis. Histology will demonstrate non-caseating granulomas; this is confirmatory not diagnostic.
Figures #1 and #2 show T1 weighted axial MR images following intravenous gadolinium administration. Note the marked diffuse meningeal thickening and enhancement.
The features of this case can also refer to another granulomatous disorder which is very rare. Idiopathic hypertrophic cranial pachymeningitis (IHCP) is also a diagnosis of exclusion. Typically this presents with headache, cranial nerve palsy, and ataxia. Imaging shows thickened enhancing meninges, CSF and serology are also non-specific. A feature reported to differentiate this from sarcoid is absence of increased serum angiotensin converting enzyme. Currently the entities are not readily separated, if indeed they are different.
References: Lexa,FJ, & Grossman,RI, MR of Sarcoidosis in the Head andSpine: Spectrum of Manifestations and Radiographic Response toSteroid Therapy, AJNR 15:973-982, 1994.
Seltzer,S, Mark,AS, & Atlas,SW, CNS Sarcoidosis:Evaluation with Contrast-Enhanced MR Imaging, AJR 158:391-397,1992.
Mamelak,AN, et al., Idiopathic Hypertrophic CranialPachymeningitis: Report of three cases, J Neurosurg 79:270-276,1993.

Submitted by:Jeffrey L. Sunshine, M.D.Craig Kamen, M.D.Albert J. Cook, M.D.Neuroradiology