A 23-year-old Chinese woman had originally presented to another hospital with a 3-year history of right-sided proptosis. Lipoma was diagnosed at the time, and a tumor resection was performed. After a recurrence, she was referred for further management.
On ocular examination, there was proptosis of the right eye with chemosis, hyperemia and limitation of eye movements. A palpable mass was found at the medial canthus. The mass was firm and ill-defined. Her visual acuity visual acuity was 20/40 in the right eye and 20/20 in the left eye. The intraocular pressure, and fundi examination were normal. She had no other contributory non-ocular findings, including chest radiograph.
Magnetic resonance imaging (MRI) of orbits showed an irregular shaped tumor in right orbit. T1-weighted showed a medium inhomogeneous high signal in the right orbit (). T2-weighted showed a mixed high signal mass in the nasal orbit involving medial rectus muscle. There were no obvious abnormalities in the surrounding orbital floor. (). The patient underwent an anterior orbitotomy for tumor resection with a clinical diagnosis of malignant tumor. Intraoperatively, the mass was covered by a thin layer of fibrous tissue. The histopathological examination of the whole tumor tissue was done.
A:T1-weighted (MRI); B:T2-WI showed an inhomogeneous signal, irregular shaped soft-tissue mass in the right orbit involving the medial rectus muscle and the muscle cone. The mass is still normal-defined
Histopathological findings revealed the diagnosis of dedifferentiated liposarcoma. Histologically, the tumor was composed of adipocytes including areas of dedifferentiation. The adipocytes were of varying sizes, with deep staining nuclei. The dedifferentiated components were composed of spindle-shaped cells, resembling a fibrosarcoma. There were often mitotic figures (,). Immunohistochemically, the tumor cells were positive for CD99, CD34, vimentin, S-100, Bcl-2, CD68, SMA, and mostly positive for ki-67.
Figure 2 A:Histopathologically, it showed the well differentiated strcuture, the adipocytes were of varying sizes, with deep staining nuclei (white arrow) (hematoxylin-eosin; original magnification x100). B:The non-liposarcoma components were composed of spindle-shaped (more ...)
Following surgery, the patient received a course of postoperative radiotherapy in other hospital.
She was followed up for 16 months. There was no evidence of recurrence. On the last follow up examination, there was an exotropia in the right eye. There was no proptosis of right eye. Her visual acuity was the same result as pre-operation, intraocular pressure was 16mmHg in the right eye and 18mmHg in the left eye. Both optic discs were normal. There was no evidence of the radiation retinopathy and radiation optic neuropathy. The MRI imaging of both orbits showed that there was no recurence of tumour mass in the right orbit in the last follow up examination (,).