June 2001: 61 year old woman
with confusion and obtundation
Contributed by: J. Barron, M.D.', S. P. Lownie, M.D.1,
D. H. Lee, M.D.2, R. R. Hammond, M.D.l1
Departments of 'Pathology and *Clinical Neurological Sciences, University of Western Ontario

Clinical History

A 61 year-old female was found in her home moaning and unresponsive. She was taken to hospital where
she was uncooperative and too obtunded to provide a
history. According to her daughter, there was a 3-week
history of progressive confusion, lethargy, headaches,
and reduction in her spontaneous speech. On neurological examination she was disoriented and had a mild
expressive aphasia. She was profoundly demented,
unable to recognize her own daughter. Papilledema was
noted as well as a right pronator drift.
Investigations included imaging of the head by CT
and MRI (Figure l ) , as well as cerebral angiography. A
5 cm. medial left frontal enhancing mass was identified.
It distorted the frontal horn of the left lateral ventricle
and inferiorly impinged on the left optic nerve. In addition, a large ( 2 cm) calcified partially thrombosed right
Carotid-oPhthalmic artery aneurysm was noted. The
patient underwent a left frontotemporal craniotomy and
near-complete resection of the tumor, apart from a small
portion adherent to the left anterior cerebral artery.

arranged in fascicles, bands, and storiform patterns (Figure 2b). Elsewhere, pleomorphic and multinucleated
cells were more widely dispersed on a myxoid background (Figure 3). The vascular bed was composed of
variably sized capillary and sinusoidal vessels. Mitotic
figures were easily found throughout the tumor with an
average of 4 mitotic figured10 HPF, Individual cells
possessed a light reticulin investment. Immunohistochemical staining for actin, desmin, EMA, cytokeratin,
S100, GFAP, NSE, synaptophysin, and KPl was negative. The neoplastic cells were positive for CD34 (Figure 4), vimentin, and alpha- 1-antichymotrypsin. Proliferative markers (Ki67) revealed variable staining density with up to 25 % of cells labeling focally (1 1% average in 10 high power fields). Electron microscopy failed
to reveal features of specific lineage for the neoplastic
cells.

Gross

Intraoperatively the left frontal mass was bluish gray,
firm and well demarcated from the adjacent brain.

Figure 2.

Microscopic
Microscopically the left frontal mass showed a beterogeneous architecture with areas that were densely
cellular alternating with areas that were hypocellular
and myxoid (Figure 2a). The cellular regions were composed of highly pleomorphic, plump, spindled cells
Figure 3.

Figure 1.

Cases of the Month: April - June 2001

Figure 4.

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Diagnosis
Malignant solitary fibrous tumor
Discussion

The solitary fibrous tumor was first described as a
pleural lesion but has subsequently been reported in
numerous extrathoracic sites. Meningeal examples have
been reported but are rare (1,2,4,5). Extrathoracic
malignant solitary fibrous tumors are extremely rare and
have not been reported previously intracranially.
Anaplastic features including areas of increased cellularity, necrosis, nuclear atypia, and greater than 4
mitoses/lO high power fields are felt to be associated
with aggressive behavior (6) although the collective
experience is limited.
The differential diagnosis includes hemangiopericytoma, anaplastic meningioma and malignant fibrous histiocytoma. As with any poorly differentiated tumor, cell
lineage must be extensively investigated using immunohistochemistry and electron microscopy. CD34
immunostaining is helpful in distinguishing solitary
fibrous tumors from other considerations. Solitary
fibrous tumors display diffuse strong CD34 expression
in contrast with other entities in the differential where
CD34 staining is mostly limited to the vascular bed (3).
In follow-up 2 months after surgery, the patient’s
dementia had improved markedly. She was completely
oriented, although short-term memory was still
impaired. She was independent in daily activities. CT
scans showed no residual tumor. Cerebral angiography
at 3 months postoperatively remarkably showed near
. complete spontaneous thrombosis of the right carotidophthalmic aneurysm.
Adjuvant radiotherapy was given. At the time of submission, 10 months postoperatively, she continues to do
well with only mild occasional headaches.

Perry A, Scheithauer BW, Nascimento AG (i997) The
immunophenotypic spectrum of meningeal Hemangiopericytoma: a comparison with fibrous meningiorna and solitary fibrous tumor of meninges. Amer J Surg Path 21:
1354-1360
Prayson RA, McMahon JT, Barnett GH (1997) Solitary
fibrous tumor of the meninges. J Neurosurg 86: 10491052
Slavik T, Bentley RC. Gray L, Fuchs HE, McLendon RE
(1 998) Solitary fibrous tumor of the meninges occurring
after irradiation of a mixed germ cell tumor of the pineat
gland. Clin Neuropatholl7:55-60
Vallat-Decouvelaere AV, Dry SM, Fletcher CD (1998)
Atypical and malignant solitary fibrous tumors in extrathorack locations. Amer J Surg Patholl22: 1502-1511

Acknowledgments

Dr. Ken Berean, Vancouver General Hospital, for his
clinical expertise. Laurel Hammond and Kris Milne,
UWO,for assistance preparing the report and graphics.
References
1. Carneiro SS, Scheithauer BW, Nascimento AG, Hirose T,
Davis DH (1996) Solitary fibrous tumor of the meninges;
a lesion distinct from fibrous meningioma. Amer J Clin
PathollO6:217-224
2. Challa VR, Kilpatrick SR,Ricci P, Wilson JA, Kelly DL Jr
(1998) Solitary fibrous tumor of the meninges. Clin Neuropath 17; 73-78

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Cases of the Month: April June 2001

Abstract
Cases of the Month, April-June, 2001
The April Case of the Month (COM).The contributors report a case of a 70 year-old woman with recurrent meningiornas, one of which showed rhabdoid
and lipomatous differentiation. Histopathological
study of the first and second previous resections
showed only typical meningothelial meningioma. On
the third craniotomy, a new tumor Specimen showed
an admixture of classic meningothelial meningioma
with lipomatous and rhabdoid foci. Immunohistochemical studies showed diffuse reactivity for
epithelial membrane antigen and vimentin, as well as
focal positivity for desmin and smooth muscle actin
in the areas with rhabdoid features and S100 protein
In the lipomatous foci. The presence of these three
different and concomitant histological patterns only
In the third surgical resection might support a metaplastic origin and, also, corroborates the concept
that rhabdoid features are suggestive of an aggressive behavior.
The May COM. A 32-year-old woman with a history of previous mastoid surgery presented with bilateral extremity weakness and ambulatory Instability.
MRI revealed a dural-based mass completely encirCling the upper cervical spinal cord. Workup was
significant for an abnormally elevated c-ANCA,positive at a dilution Of 1:128. A portion of the lesion was
removed by a posterior surgical approach to decompress the cervical cord. Histologic examination of
the dura showed a dense granulomatous infiltrate
with vasculitis and giant cells; coupled with the positive c-ANCA, the Process was felt to be most consistent with Wegener’s granulomatosis. Wegener’s
granulomatosis infrequently inVOlVeS the dura or
meninges and has not Previously been reported to
affect dura of the Cervical cord. Symptomatic
Improvement followed surgical decompression and
high-dose corticosteroid therapy, with resultant resolution of an elevated c-ANCA titer.
The June COM. A 61 year old female presents with
a three week history of Increasing confusion, lethargy and headache. A neurological exam revealed disorientation, mild expressive aphasia, bilateral
papilledema, and a right pronator drift. She had a
craniotomy and resection of tumor. The tumor histologically was consistent with a solitary fibrous
tumor displaying malignant features of hypercellularity, marked nuclear atypia, high mitotic activity,
and a high proliferation index.
This case Is unique as the first malignant variant
Of solitary fibrous tumor to be reported Intracranial-

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Cases of the Month: April June 2001

For a more complete discussion of these cases, additional
micrographs and information regarding submission of cases,
please access the WWW at: http://www.brainpathology.com.
We welcome comments about these or similar cases our readers may have encountered,

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