Brain Pathology 7: 713-714 (1997)

CASE OF THE MONTH

August 1996 = Frontal Lobe Tumor in I 1 Year Old Girl

Contributed by: Ronald Hamitton, M.D. University of Pittsburgh School of Medicine, Division of Neuropathdogy, Pittsburgh, PA U.S.A.

Clinhl History This 11 year old girl presented with a history of

left temporal headaches for over 8 months with new onset of M-, vomiting and increasing severity of headaches. A CT scan 6 months prior to this presen- tation was reported as normal. She had no other medical or psychological problems. -

MRI scans demonstrated a tumor in the frontal lobe which was isodense to brain on T-1 weighted images. The lesion was hyperintense in both T-2 weighted and proton density weighted images (Fig. 1). After contrast administration, there was little 'enhancement of the tumor.

M V Touch preparation at intraoperative consult

showed numerous cells, often appearing individual- ly, but also present in clumps. The cells had minimal cytoplasm and round to slightly oval nuclei with delicate chromatin and minimal pleomorphism. The eosinophilic background was primady granuliir in nature, although in some areas it appeared more fibrillax. There were no mitoses or necrosis. The impression was of a primary CNS neoplasm with a differential given of central neurocytoma VJ. oligo- dendroglioma vs. estheJioneuroblastoma.

Paraffin embedded material showed a cellular neoplasm containing a fairly monomorphic popula- tion of cells (Fig. 2) with round to slightly oval nuclei containing delicate duomatin. There were no nucleoli and only rare mitotic figures. In a few areas the cells were more pleomorphic and sometimes clumped together, but there were no m e ganglion cells and no Homer-Wright rosettes. In many areas there was clearing around the nuclei pig. 2, inset) reminiscent of that seen in oligodendrogliomas. There were rare calcifications. There was no endothe- lid proliferation or necrosis. The tumor invaded the surrounding brain in a broad front pattern rather than diffusely jnfilmtive.

Ii I I

? rigure 2.

714 August Case ofthe Month

Immunohistochemical ~taln showed ~trong, dif- fuse positive staining for synaptophysin (Fig. 3A). GFAP stains showed scattered positive cells withh the tumor which resembled reactive astrocytes. These same cells stained with $100. A Bielschomky stain showed neurod processes within the tumor

Electron microscopy demonstrated tumor cells to contain dense core granules and miaotubules as well as seaetory vesicles. No synaptic structures were identified (Fig. 4). '

Diagnosis

(central) Neurocytoma

centtal neumcytoma.5 are typically intra-ma- lar tumors in young adults. Over 100 cases have been reported since the entity was first described in 1982. The m6st common location is near the fora- men of Mann, or in the septum pelluddum. Neura- cytomas are rare before age 10 years, but over 6096 occur between the ages of20-40 (1).

Radiologiw, the tumors are identified as intra- ventricular masses, which are sometimes quite large. Cald5cation can be idenaed by CT scans.

Grossly, the tumor is typically welldemarcated from the surrounding tissue and usually grayish and friable. About 4096 have a gritty texture due to numerous microcalacations.

Miaoscopically the tumor cells have round nuclei with a delicate 'salt and pepper' chromatin pattern. There is scanty or ffl de5ed cytoplasm and the cells are embedded in an eosinophilic matrix which has a 5 e , flbrlllattexture. Clear cell areas are often present. In other areas, the monotonous cellu- laxity may be punctuated by patches of matrix.. Sometimes tumm cells may exhibit a streaming pat- tern. Rosettes are rarely reported. Neaosis and endothelial proliferation are rare and mitoses are uncommon. Immunohistochemically, the tumors are strongly positive for NSE and synaptophysin. 'hmor cells are generally negative for GFAP.

Electron miwscopy invariably shows numerous 60-160 nm dense core granules and 40-60 nm clear vesicles as well as miaotubules. Synaptic formation is a confirmatory 5- but is not invariably pre- sent.

This case was unusual because the tumor was located in an extraventricular site. There have now been several reports of neurocytomas occurring in the cerebral hemispheres (2,3,4) as well as in the spinal cord (5). These cases appear to have outcomes as favorable as their more common intxaventricular brethren.

1.

2.

Hassoun J, Soylemezoglu F, Gambarelli D, Figarella- Branger D, Von Ammon K, Kleihues P (1993) Central neu- rocytoma: a synopsis of clinical and histo!ogiil features. Brain Pathdogy 3: 297308. Nishio S, Takeshitu I, Kaneko Y Fukui M (1992) Cerebral neurocytoma. A new subset of benign neuronal tumors of the cerebtum. Cancer 70: 529537

Rglm 4.

3. Harada M, Monoka T, Nishio S, Fukui M (1991) Neurocytqma in the left frontal lobe. No Shinkei Geka 19: 89-92 Sgourose S, Jackowski A, Carey MP (1994) Central new rocytoma without intraventricular extension. Surg. Nwd 42:33!5-33!3 Louis DN, Swearinger 8, Linggood RM, Dckenson GR, Kretshman C, Bhan AK, Hedley-Whyte ET (19901 Central nervous system neurocytoma and neuroblastoma in adub - report of eight cases. J Neuonnmc9: 231-238,

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An 11 yoar old girl presented with an 8 month hktory of left temporal headaches with new onset .of MUM and vomiting with increased severity of headaches. An MRI scan showed a frontal lobe mass. The tumor was resected and hirtdogk stud- ies damonstmted a central neurocytoma. The dini- cal, radiologic and pathologic aspects (including immundrlrtochemktry and electron mierorcopy) of central neuroytomas am r w l d and tha atypical features of thb case desdbed.

micrographs please access this case on the WWW at: h n p ~ ~ ~ . u p m c . e d u l d i v i s i o n s E n e u r o p a t h / 5 . ht ml. We welcome comments about these or similar cases wr readers may have encountered.