Magnetic resonance imaging features of solitary inflammatory brain masses

Relapsing-remitting tumefactive multiple sclerosis

Tumefactive multiple sclerosis (MS) is a rare form of demyelinating disease. The natural course of the disease has been characterized as presenting with a mass-like demyelinating lesion converting to typical relapsing-remitting disease with future exacerbations. Herein we describe a case of a patient whom over a six-year period developed relapsing-remitting tumefactive MS. The natural course, pathophysiology, prognosis and diagnosis are briefly discussed.

Chronic inflammatory demyelinating polyradiculoneuropathy with tumefactive central demyelination

A 46-year-old man with a 1-year history of distal paresthesias and mild distal weakness subacutely developed paralysis of the left hand. Electrodiagnostic evaluation revealed a demyelinating peripheral neuropathy that met criteria for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Magnetic resonance imaging of the brain revealed a mass that enhanced with contrast, but revealed focal myelin loss with intense macrophage activity and axonal preservation on biopsy. The mass and hand weakness improved following steroid therapy. The combination of CIDP and central demyelination with mass effect broadens the spectrum of demyelinating disease in association with CIDP.

Cerebral venous infarctions presenting as enhancing space-occupying lesions: MRI findings

Cerebral venous thrombosis is an unusual form of cerebrovascular disease that may cause cerebral venous infarction (CVI). Magnetic resonance imaging (MRI) of the brain may improve the often elusive diagnosis of CVI. However, the sensitivity, specificity, and full spectrum of such MRI findings are poorly understood. The authors present the cases of three patients with CVI whose MRI scans showed abnormally enhancing tumor-like brain lesions. Two of the CVIs were hemorrhagic and exerted mass effect. One patient showed increasingly nodular and heterogeneous ring-like enhancement progressing from the single-dose to the triple-dose gadolinium contrast images. The CVI of a second patient also showed ring-like enhancement. Biopsy was performed on one of these patients and was strongly considered for the other two patients to exclude neoplastic disease. Careful examination of the MRI appearance of venous structures and the use of specialized MRI techniques improved the recognition of CVI for two patients and prevented biopsy. This represents the first description of abnormal triple-dose MRI contrast enhancement in CVI. Consideration of CVI in the care of patients with enhancing tumor-like masses may lead to earlier diagnosis and treatment, preventing unnecessary invasive diagnostic procedures. CVI should be added to the differential diagnosis of supratentorial ring-enhancing masses.