Osteoblastoma arising from the orbital roof
Zouheir Hafidi1,&, Rajae Daoudi1
1Université Mohammed V Souissi, Service d’Ophtalmologie A de l’hôpital des spécialités, Centre hospitalier universitaire, Rabat, Maroc
Zouheir Hafidi, Université Mohammed V Souissi, Service d’Ophtalmologie A de l’hôpital des spécialités, Centre hospitalier universitaire, Rabat, Maroc
Osteoblastoma is a rare benign osteogenic bone neoplasm; it represents
1 to 3% of all bone tumors and usually seen in the second decade
of life with a predilection in males. Classically it develops in
the vertebral column.
The skull is rarely involved and the orbital roof was reported
to be less frequently involved. We report a new case of a benign
from the orbital roof with an intracranial and intra orbital extension.
A 28-year-old woman presented with a recent history of rapidly
progressive left exophthalmos, unilateral vision loss and headache.
Her medical history
was unremarkable. At examination there was a downward proptosis
of the left eye with complete ophthalmoplegia. Visual
acuity was 20/200 in
the left eye with an increased intraocular pressure. Funduscopy
revealed subtotal optic nerve cupping. On computed tomography there
was a well sumscribed
hyperdense mass arising from the horizontal part of the frontal
bone with intraorbital and anterior cranial fossa extension.
Magnetic Resonance Imaging showed a homogeneous extraconal mass
with low signal intensity
on T1-weighted imaging, there were an anterior displacement of
the left eyeball
which was compressed by the tumor and a superior displacement of
the left frontal lobe. This was consistent with a frontal
A complete surgical removal was decided. This was performed within
a left-sided subfrontal approach with extradural exposure of the
anterior skull base.
Histopathological examination revealed a mature benign osteoblastoma.
Postoperatively the patient resolved her proptosis. However the
visual acuity remained unchanged.
The main differential diagnosis of osteoblastoma is osteoid osteoma.
Osteablastoma typically involves the axial skeleton and exhibits
a high growth potential,
while the osteoid osteoma occurs in the long bones and is much
less aggressive. On computed tomography osteoblastoma presents
typically as a dense, sclerotic,
homogenous mass with well-defined margins and
thin cortical margin. On MRI the tumor generally shows low-signal
intensity on both T1 and T2 weighted studies without gadolinium
of tumor location a total resection should be attempted to avoid
local recurrences; which is pretty difficult when there is a cranial
base extension. Adjuvant
radiotherapy for residual tumor may then be discussed.
: A): proptosis of the left eye with total ophthalmoplegia; B): coronal computed tomography (CT) and Three dimensional CT image of the cranium showing a right hyperdense intraorbital mass of the horizontal part of the frontal bone arising from its lateral side (black arrows) with an extension to the endocranium (star)
C): Magnetic Resonance Imaging showing anterior displacement and compression of the left eyeball (white arrows) and the frontal lobe (white arrowheads)