Lipoma of corpus callosum

Clinical History

A 2-week -old hypotonic newborn infant was presented with generalised seizures.

Imaging Findings

We present the case of a newborn infant, born by uncomplicated SVD. The infant was noted to be hypotonic at birth and soon afterwards, it developed generalised seizures. No dysmorphic features were noted. The remainder of the neurological examination was normal. In view of the seizures and hypotonia, the patient was referred for neuroradiological imaging. Cranial ultrasound, non contrast CT, and MR imaging were performed. On the basis of these imagings, a lipoma with associated hypogenesis of the corpus callosum was diagnosed.

Discussion

Intracranial Lipomas are due to maldevelopment of the embryonic meninx primitiva (the undifferentiated mesenchyme that surrounds the developing brain). Instead of developing into leptomeninges and cisterns, it madifferentiates into fat, resulting in intracranial lipomas. Because they are malformations, and not neoplasms, the lipoma cells do not multiply. The lipoma cells do hypertrophy when the patients gain weight, but they almost never exert a mass effect. The most common locations where intracranial lipomas occur the deep interhemispheric fissure (40%–50%), the quadrigeminal plate/supracerebellar cisterns (20%–30%), the interpeduncular cisterns (10%–20%) and the cerebellopontine cisterns (about 10%). Lipomas which occur in the suprasellar and quadrigeminal plate cisterns are typically small, whereas in contrast, lipomas which occur in the interhemispheric fissure and sylvian fissure may be quite large. Interhemispheric lipomas (commonly called "lipomas of the Corpus Callosum" despite being separate from the corpus) are almost always associated with agenesis of the corpus callosum. In addition, a whole spectrum of midline developmental disorders appears to have an association with lipomas of the interhemispheric fissure, ranging from midline cutaneous lipomas at the more minor end of the spectrum to the anterior midline encephaloceles at the more serious end. Skull radiographs may appear to be be normal, or may reveal curvilinear calcification with adjacent lucencies of fat density in large interhemispheric lipomas. CT demonstrates the presence of sharply demarcated areas of hypodensity in the affected cisterns, with or without the associated areas of calcification. The MR appearance of intracranial lipomas is that of a mass lesion that is hyperintense on T1WI, hypointense on T2WI, and isointense to gray matter on fat saturation sequences. Blood vessels and cranial nerves almost always course through lipomas and these appearances can also be seen on MR imagings.

Differential Diagnosis List

Final Diagnosis

Lipoma of the corpus callosum.

URL:	https://eurorad.org/case/3025
DOI:	10.1594/EURORAD/CASE.3025
ISSN:	1563-4086