PMC4109171_01
Preoperative brain MRI. T1-weighted postcontrast image, sagittal (a), axial (b), coronal (c) views revealed a heterogeneous enhancing mass lesion with several foci of cystic change over inferior fourth ventricle, about 3.2 x 3 x 2.6 cm, and extension to foramen magnum, causing mild dilatation of fourth ventricle
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F1
This tumor showed heterogeneous enhancement with several foci of cystic change in postgadolinium enhancement study [Figure 1].
Intraoperative picture showed a mass lesion arising from the dorsal side of medulla oblongata with extension into inferior fourth ventricle
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F2
Grossly, the tumor was soft and gray-red [Figure 2], quite circumscribed but the margin between the tumor and the dorsal side of medulla was not very clear.
Histology of the tumor. H and E, x200 (a) shows the specimen composed of sheets of large anaplastic cells divided by delicate fibrovascular septae with small lymphocytes, mitosis and necrosis. CD117 stain (b) shows the positive staining
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F3
Histology examination showed that the specimen composed of sheets of large anaplastic cells divided by delicate fibrovascular septa with small lymphocytes [Figure 3a]. The immunohistochemistry results of neoplastic cells revealed positive for CD117 and placenta alkaline phosphatase [Figure 3b], but negative for CD3, CD20, and synaptophysin immunostains.
Immediate postoperative brain MRI. T1-weighted postcontrast image, sagittal (a), axial (b), coronal (c) views showed the completed removal of the tumor in the inferior portion of fourth ventricle and foramen magnum
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F4
Although her immediate postoperative brain MRI showed no evidence of abnormal enhancing mass lesion, or abnormal leptomeningeal enhancement in the brain [Figure 4], we administered postoperative adjuvant radiotherapy as following dosage: Total 45 Gy on the tumor bed and total 30.6 Gy on the ventricle system.
1-year postoperative brain MRI. T1-weighted postcontrast image, sagittal (a), axial (b), coronal (c) views demonstrated neither residual nor recurrent tumor
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F5
The latest brain and whole spine MRI done 12 months after the surgery showed no abnormal enhancing tumor in the whole axis [Figure 5] and is on regular follow-up at our out-patient department.