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Neuroradiology Case of the Week

Case 130

Ravinder Sidhu, MD and Per-Lennart Westesson, MD, PhD, DDS

Clinical Presentation: A 6-year-old male child presented with history of seizures and developmental delay.

Radiological Findings: Non-contrast CT head showed a hypodense lesion with speckled peripheral calcification located within the corpus callosum region (Fig.1A & B). Axial T1-weighted MR image showed hyperintense lesion within the corpus callosum region. T2- weighted axial image showed the lesion to be of hyperintense signal, thereby suggestive of fatty nature of the mass (Figs. 2A&B & 3A&B). Sagittal T1-weighted MR image shows thinned out corpus callosum with curvilinear lipoma. A note is made of sinusitis also (Fig. 4). Coronal post contrast images shows high riding third ventricle (Fig. 5).

Discussion: Intracranial lipomas are very rare tumors. They may constitute 0.1% of all intracranial tumors. The pathogenesis of corpus callosum lipoma is controversial. Lipomas are variously considered to be derivative of embryological meninx primitive, or hyperplasia of leptomeningeal fat cells. Corpus callosum lipoma can be an isolated anomaly or associated with other anomalies such as agenesis of corpus callosum, Chiari II, interhemispheric cyst, or migrational anomalies. The most common location of intracranial lipoma is the corpus callosum. Other common locations are quadrigeminal cistern, cerebellopontine angle cistern, and choroid plexus region.
      CT clearly shows markedly hypodense attenuation reflecting fatty nature of the lesion. MR is superior to CT as it can diagnose associated structural anomalies also. Sagittal MR image depicts the corpus callosum in great anatomical detail. MR shows hyperintense mass on T1 and T2-weighted images. No enhancement is seen in post-contrast images.

References:

1. Georgy BA, Hesselink JR, Jernigan TL (1993) MR imaging of the corpus callosum. AJR Am J Roentgenol. 1993 May;160(5):949-55. [Medline]
2. Rubio G, Garcia Guijo C, Mallada JJ ( 1991) MR and CT diagnosis of intracranial lipoma. AJR Am J Roentgenol. 1991 Oct;157(4):887-8. [Medline]