Cerebral Medulloepithelioma with Long Survival —Case Report—

p428 p.1 [100%] Neurol Med Chir (Tokyo) 47, 428¿433, 2007 Cerebral Medulloepithelioma With Long Survival —Case Report— Masato MATSUMOTO,KazuomiHORIUCHI,TakuSATO, Masahiro OINUMA, Jun SAKUMA,KyouichiSUZUKI,TatsuyaSASAKI,NamioKODAMA, Kazuo WATANABE*, and Toshimitsu SUZUKI* Departments of Neurosurgery and *Pathology, Fukushima Medical University, Fukushima, Fukushima Abstract An 8-year-old boy presented with a rare cerebral medulloepithelioma manifesting as headache, nausea, and vomiting. Neuroimaging demonstrated a mass containing a cyst in the left frontal lobe. Gross total resection of the tumor with a 1-cm margin was performed under intraoperative monitoring. The histological diagnosis was medulloepithelioma. Stereotactic radiotherapy (total dose 20 Gy) was given to the brain up to 1 cm from the surgical margin. Follow-up neuroimaging 5 years later showed no signs of recurrence. He now attends junior high school, with normal mental and physiological development. Medulloepitheliomas are rare, highly malignant embryonal tumors of the central nervous system. Combined gross total tumor resection and radiotherapy are recommended to obtain the most favorable outcome. Key words: medulloepithelioma, cerebrum, prognosis, surgery, radiation Introduction Case Report Medulloepitheliomas, first described by Bailey and An 8-year-old boy was admitted to our hospital Cushing in 1926,2) are rare, highly malignant primi- because of headache, nausea, and vomiting in tive neuroectodermal tumors usually occurring in March 2000. Neurological examination on admis- childhood. Histologically, they resemble the primi- sion showed bilateral papilledema. Routine hemato- tive medullary plate and neural tube.2,28,35) The most logical study disclosed no abnormalities. Computed common site is periventricular within the temporal, tomography (CT) revealed a well-circumscribed parietal, and frontal lobes, in that order.9,11,13,21,22, heterogeneous isodense mass containing a cyst in 44,45,47) These neoplasms are believed to arise from the left frontal lobe, with heterogeneous enhance- primitive undifferentiated matrix cells around the ment with contrast medium (Fig. 1). T1-weighted periventricular area.35) The high rate of recurrence magnetic resonance (MR) imaging showed an isoin- due to rapid subarachnoid spread and radioresis- tense mass, heterogeneously enhanced with gado- tance of the tumor cells results in a poor prognosis linium-diethylenetriaminepenta-acetic acid (Gd- with overall median survival of 5 months.1,3,4,6,9,11, DTPA), containing a cystic component, and hyper- 13,21,22,25,28,32,35,38,43–45,47) Long-term survivors had un- intense areas suggestive of intratumoral hemorrhage dergone gross total resection.25,28,46) (Fig. 2). The preoperative diagnosis was anaplastic We report a case of medulloepithelioma with long- ependymoma. term survival of more than 6 years in a 13-year-old Left frontotemporal craniotomy exposed the boy treated by gross total resection and removal of reddish tumor which was well demarcated from the the surrounding brain tissue infiltrated by tumor adjacent brain (Fig. 3). The tumor was soft and cells. contained a cyst with bloody fluid. The tumor was totally removed after coagulation of the adhering falx. In addition, the surrounding brain was excised to a depth of 1 cm from the margin of the tumor Received October 24, 2006; Accepted June 12, 2007 cavity because intraoperative histological study of 428 p428 p.2 [100%] Cerebral Medulloepithelioma 429 Fig. 1 Computed tomography scans showing a mixed density mass in the left frontal lobe (A), and heterogeneous enhancement of part of the tumor with contrast medium (B). Fig. 4 Photomicrographs of the tumor showing neural tube-like structures with a pseudo- stratified epithelium and internal and external limiting membrane (A: hematoxylin and eosin [HE] stain, original magnification × 400), mitoses near the internal limiting Fig. 2 T -weighted magnetic resonance images 1 membrane (B: HE stain, original magnifica- showing a well-circumscribed heterogene- tion ×400), rosette formation with the cen- ous mass with hyperintense areas sugges- tral lumen (C) and choroid plexus elements tive of hemorrhage (A), and heterogeneous (D) (C, D: HE stain, original magnification enhancement of the mass by gadolinium (B). ×400), tumor cells infiltrating into the adjacent parenchyma (E: HE stain, original magnification ×200), and positive immuno- histochemical staining for AE1/AE3 at the luminal border of the neural tube-like structures (F: original magnification ×400). frozen sections showed infiltration by tumor cells. Intraoperative monitoring of motor evoked poten- tial20,41) and somatosensory evoked potential showed no changes during resection of the tumor and surrounding brain. Histological examination found various neural tube-like tubular, capillary, and trabecular structures composed of pseudo-stratified primitive neu- Fig. 3 Intraoperative photograph showing a mass roepithelium (Fig. 4A, B). These structures were well demarcated from the surrounding clearly separated from each other by a basement brain. The tumor adhered to the falx membrane positive for periodic acid-Schiff staining. (arrows). The pattern-less cellular areas contained many immature rosette-like structures (Fig. 4C). Vascular proliferation necrosis and calcification were com- Neurol Med Chir (Tokyo) 47, September, 2007 p428 p.3 [100%] 430 M. Matsumoto et al. mon. Foci of choroid plexus-like configurations into glioblasts, i.e. precursors of astrocytes and were also observed (Fig. 4D). Tumor cells had in- oligodendrocytes.14) The glioblasts rapidly migrate filtrated into the surrounding brain tissue (Fig. 4E). outward and retain their mitotic activity. Cells The neural tube-like structures were immunoposi- remaining near the lumen of the neural tube develop tive for cytokeratin (AE1/AE3) (Fig. 4F), and the the features of differentiated ependymal cells. Glial undifferentiated areas were positive for glial fibrilla- cell differentiation occurs during the third stage of ry acidic protein and synaptophysin staining. There cytogenesis.21) Ependymal differentiation is suggest- was no immunoreactivity for epithelial membrane ed by cytokeratin reactivity at the luminal surface, antigen, collagen type IV, alpha-fetoprotein, or indicating the maturation of residual germinative carcinoembryonic antigen. The MIB-1 index for cells located next to the lumen of the original neural proliferative activity was 41.8% for tumor cells in tube, also occurring in the third stage.46) highly cellular portions and 15.5% for those in other The present tumor exhibited some features of overlying areas. ependymal and choroid plexus differentiation. His postoperative course was uneventful and the Moreover, some of the internal and external limiting symptoms attributable to hypertensive intracranial membranes were immunopositive for AE1/AE3. pressure were resolved. He manifested no neurologi- These findings correspond with the third stage of cal deficits. The area up to 1 cm from the surgical cytogenesis. The present tumor was also im- margin was treated with stereotactic radiotherapy munoreactive for vimentin, the first intermediate (total dose 20 Gy). MR imaging obtained 5 years after filament protein demonstrated in the early develop- the operation detected no residual tumor or recur- mental stage of the mammalian neural tube.6,36) rence. At present, the patient attends junior high Medulloepitheliomas may express all stages of cen- school, and his mental and physiological develop- tral neurogenic maturation, from the most em- ment is normal. bryonal to the most differentiated cell types, in a single tumor. It remains unknown why in some Discussion cases the neural tube becomes a malignant tumor and why some individuals develop medulloepithelio- Approximately 50 cases of medulloepithelioma have mas after birth. These tumors may derive from neu- been reported (Table 1).1–19,21–40,42–45) Although most ral tube-like tissue either as a result of neoplastic medulloepitheliomas manifest in the first decade of transformation at some stage of fetal or early life,1,11,13,15,22,25,28,31,39,40,44) they are occasionally found postnatal development11,32,43) or from the anomalous in patients older than 20 years.25,38) These tumors gene re-expression of early neural tube deter- tend to be fatal despite treatment by surgery and/or minants.24,46) irradiation and/or chemotherapy.1,6,10,11,21,22,28,31,38, Medulloepitheliomas at initial presentation gener- 40,44) On the other hand, intraorbital,7,8,15,30) peripher- ally appear as well circumscribed, iso- to slightly al,26) and cauda equina22) medulloepitheliomas have hypodense neoplasms on CT scans,28,31) and as hypo- a much less malignant course and even those treated or hyperintense tumors on T1-andT2-weighted MR primarily or only by enucleation tend not to recur images. Medulloepitheliomas are typically not for a long time.7,15,19,27) Extracranial and intracranial enhanced by contrast medium on CT and MR imag- medulloepitheliomas have similar histological fea- ing,26) but our case showed heterogeneous enhance- tures,8,30) and the great difference in the prognosis ment with iodinated contrast medium and Gd- remains to be elucidated. In addition, the differ- DTPA. This finding may reflect the more aggressive ences in the biological characteristics and behaviors nature of these tumors at recurrence.28) Histological oftheseneoplasmsareunexplained. findings of tumor infiltration into adjacent brain Medulloepithelioma

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