American Journal of Neuroradiology 28:314-315, February 2007
© 2007 American Society of Neuroradiology
Case Report
BRAIN
Intraosseous Intracranial Meningioma
V. Agrawala,
N. Ludwiga,
A. Agrawala and
K.R. Bulsaraa
a From the Departments of Surgery and Radiology and the School of Medicine, University of Missouri-Columbia, Columbia, Mo
Please address correspondence to: Ketan R. Bulsara, MD, Duke University Medical Center, 1 Wavecrest Ct, Durham, NC 27713; e-mail: ketanbulsara{at}hotmail.com
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Abstract
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SUMMARY: Primary intraosseous lytic meningiomas are rare tumors,
with only 16 cases described in the literature. We present a
case in which CT and MR imaging with contrast agent helped diagnose
preoperatively an enlarging skull mass as a primary intraosseous
lytic meningioma in a 70-year-old woman. Radiographic findings
revealed a lytic mass centered on the coronal suture line that
separated and thinned both the outer and inner tables of the
frontal bone.
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Introduction
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Meningiomas arise from arachnoid cap cells of the arachnoid
cap villi. Primary extradural meningiomas are rare lesions,
accounting for less than 2% of all meningiomas.
1 Intraosseous
meningiomas are increasingly rare, occurring in 14% of cases
of ectopic or primary extradural meningiomas.
2 Osteoblastic
or mixed osteoblastic-osteolytic lesions compose most intraosseous
meningiomas, with purely lytic lesions the least common.
3 In
2004, Rosahl et al
4 reported 16 cases of primary intraosseous
osteolytic meningiomas without evidence of soft-tissue invasion.
We report the case of a primary calvarial osteolytic intraosseous meningioma in a 70-year-old woman.
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Case Presentation
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A 70-year-old right-handed woman presented with a progressively
enlarging painless mass over her left frontal area that had
been present for 2 years. Physical examination revealed a left
frontotemporal bony protuberance with no neurologic or other
significant findings. Noncontrast CT of the head was performed
(
Fig 1A, -
B). The lesion was further characterized by using
pre- and postcontrast MR imaging (
Fig 2A, -
B). The radiologic
preoperative diagnosis was likely an intraosseous lytic meningioma.
Percutaneous biopsy results from an outside facility in Southeast
Asia were not diagnostic.
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Fig 1. A, Noncontrast CT axial projection of a 41-mm minimally hyperattenuated homogeneous lytic mass centered at the coronal suture line with the inner and outer bony tables thinned and partially interrupted. B, Bone window exhibiting an osteolytic lesion with anterior hyperostosis. C, Axial T1-weighted precontrast MR image demonstrating an isointense biconvex mass. D, Axial T1-weighted postcontrast MR image demonstrating intense homogeneous enhancement with a mild dural reaction.
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The patient underwent microsurgical resection of her lesion (Fig 2). Intraoperatively, most of the mass was resected. However, because of anesthesia complications, the dural component was not resected. Pathologic examination revealed a hypercellular meningothelial neoplasm composed of small cells with high nuclear-to-cytoplasmic ratio, with scattered atypical nuclei with prominent nucleoli (Fig 3A, -B). Findings of pathology were consistent with a WHO grade I meningioma.
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Fig 3. A, Light microscopy (H&E; original magnification x 2) of resected tumor involving bone. B, Light microscopy (H&E; original magnification x 40) reveals sheets of small cells with uniform nuclei forming small whorls.
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Precontrast CT of the head performed 4 months following surgical resection showed no evidence of tumor recurrence. However, a postcontrast scan showed a 4.5-mm-thick area of dural enhancement adjacent to the craniotomy site, partially effacing the Sylvian fissure.
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Discussion
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As reported by Rosahl et al,
4 16 cases of primary osteolytic
intraosseous meningiomas have been published. The differential
diagnosis for a primary lytic calvarial lesion includes lytic
metastasis, epidermoid tumor, multiple myeloma, eosinophilic
granuloma, fibrous dysplasia, brown tumor, skull dermoid, lytic
intraosseous meningioma, giant cell tumor, hemangiopericytoma,
and hemangioma.
4 Although this lesion involved the inner and
outer bony tables, consistent with lesions such as eosinophilic
granulomas and hemangiomas, the lesion did not exhibit radiologic
findings completely consistent with these or other intraosseous
lesions. Additionally, primary intraosseous meningiomas tend
to present with hyperostosis, which was seen in this lesion.
5 Patients with primary calvarial lesions commonly present with
a lump in the scalp of long evolution with a relationship to
the cranial sutures.
6
Some dural invasion noted in surgery raised the question as to whether the tumor could be classified as a primary extradural meningioma. The review of Lang et al1 of all primary extradural meningiomas concluded that extracalvarial meningiomas that erode the inner table of the skull with dural reaction and/or invasion cannot be excluded from being classified as primary extradural lesions. A lesion demonstrating tumor growth with the center outside the dura can be classified as a primary extradural meningioma.1 Radiologic and pathologic findings in our patient supported this designation.
The proposed origin in our patient may have been due to trapping of arachnoid cells in a prior healed skull fracture or to embryologic rests of arachnoid cap cells within the developing calvaria. Therefore, primary intraosseous meningioma should be considered in the differential diagnosis when a solitary lytic calvarial lesion is seen near the suture line or is associated with a prior skull injury.
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References
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- Lang FF, Macdonald K, Fuller GN, et al. Primary extradural meningiomas: a report of nine cases and review of the literature from the era of computerized tomography scanning. J Neurosurg 2000;93:940–50[Medline]
- Daffner RH, Yakulis R, Maroon JC. Intraosseous meningioma. Skeletal Radiol 1998;27:108–11[Medline]
- Levin M, Wertheim SE, Klein E, et al. Unusual lytic intraosseous meningioma. J Neuroimaging 1995;5:247–48[Medline]
- Rosahl SK, Mirzayan M-J, Samii M. Osteolytic intra-osseous meningiomas: illustrated review. Acta Neurochir (Wien) 2004;146:1245–49. Epub 2004 Sep 9[Medline]
- Lee HY, Prager J, Hahn Y, et al. Intraosseous meningioma: CT and MR appearance. J Comput Assist Tomogr 1992;16:1000–01[Medline]
- Arana E, Diaz C, Latorre FF, et al. Primary intraosseous meningiomas. Acta Radiol 1996;37:937–42[Medline]
Received October 22, 2005;
accepted after revision December 27, 2005.
TOP
Abstract
Introduction