CASE 14428 Published on 11.02.2017

Pericallosal Lipoma

Section

Neuroradiology

Case Type

Clinical Cases

Authors

Serpa S, Silva D, Dutra S, Cordeiro P, Cruz, R.

Hospital do Divino Espírito Santo de Ponta Delgada, HDES.
Patient

43 years, female

Categories
Area of Interest Neuroradiology brain ; Imaging Technique CT, MR
Clinical History
A 43-year-old female patient with hypertension and anxiety was referred to the neurology department due to numbness on the left side of the body and disequilibrium. Physical examination and laboratory findings were unremarkable. A non-contrast-enhanced cranial CT and subsequently an MRI, were performed.
Imaging Findings
The CT revealed a fat-density mass in the pericallosal area and in the interhemispheric fissure. An MRI study was performed and revealed a sharply demarcated mass, with a high signal intensity in the pericallosal area with extension into interhemisferical fissure on T1,T2 and Flair sequences and hypoplasia of the corpus callosum.
Discussion
Intracranial lipomas are rare intracranial tumours (accounting for 0.5 to 1%) [1, 2] and are found in all age groups, without sex predilection [2, 4].
These abnormal fat collections mostly occur in the subaracnoid space, usually at or near the midline [4], mainly arising in the region of the corpus callosum (more than 50%) [1-4], but also (rarely) in the ambient, suprasellar, sylvian, interpeduncular, cerebellopontine angle and superior cerebellar cisterns. Lipomas have been reported in the internal auditory canal [4].
Most authors do not take intracranial lipomas as true neoplasms and characterize these lesions as developmental malformations, representing an abnormal persistence and differentiation of the primitive meninx [1, 3, 4]. More than half of intracerebral lipomas were reported with varying degrees of brain malformations. There might be interference between the development of the midline structures and the embryological malformations of the subarachnoid spaces [4], explaining the associated hypoplasia of the corpus callosum documented in this case. Other associated anomalies include agenesis of surrounding tissues, frontal bone defects or facial dysplasia, absent/tortuous blood vessels or aneurysms, unusual branching patterns of nerves, or cranial nerve absence or duplication.
The majority of intracranial lipomas are found incidentally, as they are frequently clinically silent [1, 4], although there are some reports about symptoms like seizures (mainly), headache, and others that are presumed to be caused by a local mass effect.
CT and MRI scanning features are often pathognomonic for intracranial lipomas and help establish a preoperative diagnosis.
On CT imaging, intracranial lipomas are homogeneous hypoattenuating lesions with fat-density (-70 H.U. average), sharply circumscribed, while on MRI these lesions usually reveal homogeneous T1 and T2 hyperintensity; Fat saturation images diminish their signal. Lipomas typically do not enhance with gadolinium, and edema is not present around the lesions. Calcification is uncommon.
Intracranial lipomas have a slow growing and the prognosis is good even without treatment. A surgical approach should be considered in epileptic patients who do not respond to medical management [1, 4]. Given the high vascularity of some lesions, there is a risk of adhesion to surrounding tissues.
Differential Diagnosis List
Pericallosal lipoma
Intracranial dermoid
Intracranial teratoma
Intracranial epidermoid
Final Diagnosis
Pericallosal lipoma
Case information
URL: https://www.eurorad.org/case/14428
DOI: 10.1594/EURORAD/CASE.14428
ISSN: 1563-4086
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