Type:
Educational Exhibit
Keywords:
Neuroradiology brain, CT, MR, Diagnostic procedure, Congenital, Tissue characterisation
Authors:
N. Fileva, J. D. Dimova, D. Zlatareva, V. Hadjidekov; Sofia/BG
DOI:
10.26044/ecr2019/C-2981
Findings and procedure details
Often intracranial lipoma is an incidental finding on a head CT performed for another indication.
In some cases,
additional MRI is performed to verify the detected mass.
In both modalities most commonly they are reported as well-delineated,
oval or lobulated extra-axial fatty mass.
On CT,
lipomas appear as hypodense lesions (-50UH and -100UH) with no surrounding edema and no enhancement in the postcontrast series.
If there are any calcifications,
they are located peripherally within the surrounding fibrous capsule.
The MRI findings include lesions with fat-intensity in all sequences.
They are visualized as homogeneous,
hyperintense mass on T1W and T2W images.
In the sequences with fat saturation they have low signal intensity.
Differential diagnosis should include dermoids,
epidermoids,
teratoma,
lipomatous transformation of neoplasm or subacute hemorrhage.
- Dermoids - on CT they are described as oval or lobulated hypodense masses,
with no contrast enhancement and surrounding edema,
slight mass effect and foci of calcifications,
located aside from the midline.
On MRI they are hyperintense on T1-weighted images and heterogeneous signal on T2 weighted sequences due to the mixed components of the tumor.
- Epidermoid cysts usually have characterizations more similar to the cerebrospinal fluid,
rather than the fat tissue (on CT – again well-defined,
lobulated hypodense mass; on MRI - hypointence on T1-weighted images and hyperintence on T2-weighted images).
- Teratomas – similar locations as the lipomas,
but have more heterogeneous appearance with foci of contrast enhancement.