CASE 8967 Published on 03.11.2010

Woman with a skull deformity of long evolution (ECR 2005 Case of the day)

Section

Neuroradiology

Case Type

Clinical Cases

Authors

Ros Mendoza LH, Marín Cárdenas MA, Cacicedo Egues Y, Mazas Artasona L, Valero Palomero P, Ferrer Lahuerta E.
Department of Radiology, Hospital Miguel Servet, Zaragoza, Spain.

Patient

57 years, female

Categories
Area of Interest Neuroradiology brain ; Imaging Technique CT, MR
Clinical History
We present the case of a 57 year old woman with antecedent of hypertension. She presents a skull deformity of long evolution, according to the patient, more than one year. It is not painful and does not present any inflammatory signs.
Imaging Findings
Imaging examinations were performed and showed the following findings. Figures 1-2: Skull CT without contrast.
1) Soft tissue window. Thickening of the skull with an intracraneal mass effect, producing displacement of the middle line.
2) Osseous window. Sclerotic reaction of the bone, spiculated morphology, with a comb appearance.
Figure 3: 3D craneal reconstruction. Asymmetry and the deformity of the skull.
Figures 4-9: MR study.
4) Sagittal FSE T1, without contrast. Osteoblastic reaction in the frontoparietal area.
5) Axial FSE Pd. Thin line of cerebrospinal fluid located inside the intracraneal meningeal reaction. Internal displacement of vascular structures.
6) Axial FSE T2. The mass presents a signal intensity that is similar to that of the grey matter.
7) Axial FSE T2 FLAIR. Thickening of the meningeal structures under the sclerotic reaction of the bone.
8) Axial FSE T1, after intravenous contrast administration. Significant and homogeneous enhancement of the extracraneal mass, radial distribution of the enhancement across the skull.
9) Coronal FSE T1, after intravenous contrast administration. Intracraneal mass effect related to the osseous expansion.
Discussion
Meningiomas arise from arachnoid cells located in the inner layer of the dura mater. Those that do not arise from this location represent 1–2% of all meningiomas. They can arise from arachnoids cells located in the dura mater external layer, diploe or in an extracranial location.
These different patterns of growing and location give rise to different denominations: intraosseous meningioma, extra-cranial, extra-neuroaxial or extradural ectopic [1,2, 3]. Lang et al name them primary extradural meningiomas. They have elaborated a practical classification according to their relation to the dura mater and the growing direction: extra-calvarial (Type I), purely calvarial (Type II), calvarial with extracalvarial extension (Type III). The types II and III that involve the skull are divided into lesions of the convexity or lesions of the skull base [4].
Plate meningiomas present a great intracranial component, more or less diffuse, with sclerotic reaction and expansion of the skull. There is not a clear difference with extradural meningiomas, in the different imaging modalities, except the presence of an intracranial mass [2].
Primary extradural meningiomas usually produce a slow thickening of the skull, with sclerosis of both, the inner and outer layers, that cause cranial deformity. Type II lesions that involve the skull base cause orbital deformity and exoftalmus [2]. It is less frequent that they appear as a destructive lesion. These cases, and also those with a more aggressive and malignant behaviour [4], are usually related to convexity Type II lesions, tumours exclusively located in the skull.
The radiologic appearance is characterized by the sclerotic bone reaction, its expansion and the cranial deformity, usually unilateral. On CT the irregular growing of the bone, with a hair on appearance [5], also described as radiant pattern, perpendicular to the skull plane, is well demonstrated [3]. This case presents this specific appearance, with well-defined osseous radiations. On CT and MR, after intravenous contrast administration, a radiant enhancement [5], with a homogeneous appearance of the dural component and the extracraneal masses is evident. Both imaging modalities are useful in order to determine the extension of the lesion before the treatment.
In our case the intracranial meningeal component presented a signal that was superior to that of the brain parenchyma, because it was an inflammatory reaction, besides the intra and extraosseous component, with involvement of the muscular estructures, as the pathologic study demonstrated.
The pathologic study showed a transitional meningioma with osseous and muscular infiltration, degree I of the WHO.
Differential Diagnosis List
Intraosseous meningioma (primary extradural meningioma)
Osteoma
Paget disease
Fibrous displasia
Osteoblastic metastases
Final Diagnosis
Intraosseous meningioma (primary extradural meningioma)
Case information
URL: https://www.eurorad.org/case/8967
DOI: 10.1594/EURORAD/CASE.8967
ISSN: 1563-4086

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