Neuroradiology Case of the Month

September 2002

A. Abdelhalim, J. Echeverri, and H. Wang

Clinical Presentation: Five-year-old male with headaches and contractures.

MR Findings: There are well-defined foci of CSF-like signal intensity present in the corpus callosum and cerebral white matter. These well-defined foci are likely representing dilated Virchow-Robin spaces.

Diagnosis: Mucopolysaccharidoses.

Figures 1A&B: Sagittal T1 and axial T2-weighted images demonstrate well-defined foci in the corpus collosum and cerebral white matter. These foci follow CSF in all pulse sequences.

Discussion: The mucopolysaccharidoses are lysosomal storage disorders that result from deficiency of specific lysosomal enzymes involved in the degradation of mucopolysaccharides. Mucopolysaccharide deposits in the lysosomes interfere with the degradation of other macromolecules, resulting in the intralysosomal accumulation of other materials in addition to mucopolysacchrides. Diagnosis is made by combining the clinical picture with characteristic urinary mucopolysacchrides [1].

Imaging studies of the brain in mucopolysacchridoses are usually ordered when hydrocephalus or spinal cord compression is suspected. CT and MR usually reveal delayed myelination, atrophy, varying degrees of hydrocephalus, and white matter changes [2]. The sharply defined foci are commonly present in the corpus collosum, basal ganglia and cerebral white matter. They are isointense with CSF in all imaging sequences and are probably mucopolysacchride-filled perivascular spaces [3].

References:

1. Barkovich AJ: Pediatric Neuroimaging. Philadelphia, PA: Lippincott, Williams & Wilkins; 2000; 119-122.
2. Lee C, Dineen TE, Atell: Characterization by cranial MR imaging. Am J Neuroradiology 1993;14:1285-1292.
3. Becker LE, Yates A. Inherited metabolic disease. IN: Davis R, Robertson, Eds. Textbook of Neuropathology, 2nd Edition. Baltimore: Williams & Wilkins, 1990:331-427.