Primary pericranial Ewing's sarcoma on the temporal bone: A case report.
BACKGROUND
Primary Ewing's sarcoma originating in the pericranium is an extremely rare disease entity.


METHODS
A 9-year-old female patient was admitted to our department due to a left temporal subcutaneous mass. The mass was localized under the left temporal muscle and attached to the surface of the temporal bone. Head computed tomography revealed a mass with bony spicule formation on the temporal bone, however, it did not show bone destruction or intracranial invasion. F-18 fluorodeoxyglucose positron emission tomography showed no lesions other than the mass on the temporal bone. Magnetic resonance imaging showed that the mass was located between the temporal bone and the pericranium. The mass was completely resected with the underlying temporal bone and the overlying deep layer of temporal muscle, and was diagnosed as primary Ewing's sarcoma. Because the tumor was located in the subpericranium, we created a new classification, "pericranial Ewing's sarcoma," and diagnosed the present tumor as pericranial Ewing's sarcoma.


CONCLUSIONS
We herein present an extremely rare case of primary pericranial Ewing's sarcoma that developed on the temporal bone.
Department of Neurosurgery. Shiga University of Medical Science, Setatsukinowa-cho, Shiga, Japan.
Hiroto
H
Kawano
Department of Neurosurgery. Shiga University of Medical Science, Setatsukinowa-cho, Shiga, Japan.
Naoki
N
Nitta
Department of Clinical Laboratory Medicine and Division of Diagnostic Pathology, Shiga University of Medical Science, Setatsukinowa-cho, Shiga, Japan.
Mitsuaki
M
Ishida
Department of Neurosurgery. Shiga University of Medical Science, Setatsukinowa-cho, Shiga, Japan.
Tadateru
T
Fukami
Department of Neurosurgery. Shiga University of Medical Science, Setatsukinowa-cho, Shiga, Japan.
Kazuhiko
K
Nozaki
Ewing's sarcoma; pericranium; skull; temporal bone