Tumors at the Trigone of the Lateral Ventricle — Clinical Analysis of Eight Cases— Takashi ANDOH, Jun SHINODA, Yoshiaki MIWA, Toshifumi HIRATA, Noboru SAKAI, Hiromu YAMADA and Kuniyasu SHIMOKAWA* Department of Neurosurgery and *Pathological Division of Central Laboratory, Gifu University School of Medicine, Gifu Abstract Tumors at the trigone of the lateral ventricles are relatively rare. The authors have operated on eight cases with trigonal tumors during a 10-year period. Four cases were true intraventricular tumors arising from the ventricular walls, consisting of two meningiomas, one cavernous angioma, and one choroid plexus papilloma. On the other hand, the remaining four cases were paraventricular tumors originating in the adjacent brain and consisted of three astrocytomas and one glioblastoma multiforme. Although these trigonal tumors were readily detected with computed tomographic (CT) scanning, differential diagnosis was difficult because of their similar appearances on CT scans. The initial symptoms were headache in seven, and the neurological examination revealed personality changes, choked disc, visual field defects, hemiparesis, etc., in four, and no deficits in the remaining four cases. All cases were operated on <I>via</I>superior or middle temporal gyrus incision, and the sur gical results were good except for one case who died of postoperative brain edema. In the four cases with tumors located in the dominant hemisphere, two were left with sensory aphasia, dyslexia, dyscalculia, and hemianopsia which improved within 6 months. In these two cases, postoperative CT scans revealed cerebrospinal fluid retention with severe edema along the surgical route which disappeared spontaneously within 3 months. We consider that the temporal gyrus incision was the safest approach, even though the tumor was located in the dominant side. Key words: intraventricular tumor, trigone, computed tomography, angiography, surgical approaches Introduction between 1977 and 1987 (Table 1). Their ages ranged from 5 to 62 years, seven cases being adults aged over Tumors at the trigone of the lateral ventricle are rela 30 years, and one case with pilocytic astrocytoma tively rare and asymptomatic, and their incidental aged 5 years. The preoperative diagnosis of menin discovery has recently increased with the wide use of gioma was comparatively easy, but subependymal computed tomography (CT). Although almost all giant cell astrocytoma,') cavernous angioma, or trigonal tumors are meningiomas, it is difficult to fibrillary astrocytoma were difficult to differentiate determine their precise nature before the operation from meningioma, and required histological con because of the various other tumors that may be firmation. Diagnoses were confirmed histologically suspected. We describe eight cases of trigonal tumors in addition to using CT scanning and cerebral with special reference to the neuroradiological diag angiography before operation. noses and surgical approaches. The cases were classified into the two groups according to Koos and Laubichler,'7) i.e., true intra Clinical Analysis ventricular tumors arising from the ependyma or choroid plexus and lying within the ventricular cavity Eight cases with trigonal tumor underwent surgery in four cases (2 meningiomas, 1 choroid plexus papilloma, and 1 cavernous angioma), and para Received March 27, 1989; Accepted August 15, ventricular tumors originating from the glial tissue 1989 adjacent to the ventricular walls in four cases (3 Table 1 Summary of eight cases with trigonal tumor astrocytomas and 1 glioblastoma multiforme). As II. Surgical approach the initial symptoms, seven cases complained of The tumors were removed piecemeal via the mid headache, including two of vomiting, and one of dle or superior temporal gyrus incision in four unconsciousness attack were noted. During neuro cases each. Subtotal removal was performed in Case logical examination on admission, four cases were 4 as the tumor extended to the hippocampus, and found normal while the other four had choked disc, partial removal was accomplished in Case 8 as it visual field defect, hemiparesis, and sensory distur extended to the basal ganglia. Additionally, post bance. operative radiotherapy was given in Cases 4 and 8. Total removal was accomplished in the other six I. Neuroradiological findings cases. In three cases with choked disc, the tumor size was Case 2 with a bulky meningioma, the case before larger than 5 cm. Precontrast CT scans revealed a use of the microscope, died of marked brain edema low-density mass in Case 1, an isodensity mass in due to injury of the middle cerebral artery during the Case 7, a mixed density mass in Case 8, and high operation. The other seven cases showed favorable density masses in the five remaining cases. All cases outcome, where out of four cases with lesions on showed enhancement, only mildly in Cases 6 and 8, the dominant side three cases (Cases 1, 5, and 7) but marked in the other six cases (Fig. 1). The ap showed transient aphasia, dyslexia, and homony pearances of the tumors on postcontrast CT scans mous hemianopsia, etc., postoperatively. However, showed oval-shape lesion with a sharply defined they recovered almost completely 6 months later. margin in two cases (Cases 3 and 5), while the other Cases 5 and 7 pursued a very interesting course. six cases had various shapes with irregular margins. Postoperative CT scans revealed cerebrospinal fluid Calcification was noted in Cases 1 and 6. Hydro (CSF) retention associated with edema in the tem cephalus was not present in any cases, but the infe poral lobe adjacent to the trigone was noted along rior horn of the ipsilateral ventricle was apparently the corticotomy route (Fig. 3). This disappeared as dilated in three cases (Cases 5-7). the symptoms improved. Cerebral angiography revealed homogeneous over shadowing in three cases (Cases 1, 2, and 5), all of III. Representative case reports which were mainly supplied from the anterior Case 1: A 5-year-old girl suffered from headache choroidal artery (Fig. 2). In Case 2, the posterior on waking for about 1 year and was admitted to our choroidal artery was the feeder. hospital because of increased headache with vomit Fig. 1 Pre (left) and postcontrast (right) CT scans of eight cases. A: Case 1. CT scans showing a huge round hypodense mass with calcification at the anterior part, which is markedly enhanced. B: Case 2. CT scans showing a huge lobulated hyperdense mass with peritumoral edema, which is markedly enhanced. C: Case 3. CT scans showing a homogeneous hyperdense mass with marked uniform enhancement. D: Case 4. CT scans showing an ovoid hyperdense mass with marked enhancement. E: Case 5. CT scans showing a hyperdense mass with patchy hypodense areas and calcification associated with peritumoral edema, which is markedly enhanced. F: Case 6. CT scans showing an irregular hyperdense mass with moderate enhancement. G: Case 7. CT scans showing an oval isodensity with marked uniform enhancement. H: Case 8. CT scans showing a huge mixed density mass suggesting polycystic tumor with ring enhancement. markedly enhanced (Fig. IA). A left carotid angiog raphy showed a faint tumor blush supplied by an enlarged anterior choroidal artery in the arterial phase, and a uniform tumor stain in the capillary phase (Fig. 2A). The tumor, which was dark red and partially cystic with a well defined margin and attached to the lateral wall, was totally removed via the middle temporal gyrus incision. The histologic al diagnosis was pilocytic astrocytoma (Fig. 4A). She was discharged with mild right hemiparesis and right homonymous hemianopsia. Case 5: A 37-year-old male was admitted to a local hospital for head trauma and abdominal injuries caused by a traffic accident. He was transferred to our hospital because of the incidental detection of a brain tumor on CT scans. The CT scans showed a round hyperdense mass with an irregular margin which was intensely enhanced in the left trigone. Fig. 2 A: Case 1. Left carotid angiograms, arterial This lesion was partially calcified and contained (left) and capillary (right) phases, showing several foci of low-density spots accompanied by enlarged anterior choroidal artery supplying a edema of the surrounding white matter (Fig. iE). tumor with many faint blushes and uniform Left carotid angiography demonstrated a whorl tumor stain. B: Case 5. Left carotid angio formation of the anterior choroidal artery and a grams, arterial (left) and early venous (right) homogeneous tumor blush (Fig. 2B). The tumor, phases, showing whorl formation of the which was dark red, elastic and soft, and well en enlarged anterior choroidal artery and homo capsulated, was totally removed via the left superior geneous tumor blush. temporal gyrus incision. An yttrium-argon-garnet (YAG) laser was used because the tumor was ex tremely large and vascular. The histological diag nosis was choroid plexus papilloma (Fig. 4B). Post operatively, he had transient right homonymous hemianopsia, dysphasia, dyscalculia, and dysgra phia, all of which improved within 3 months. A CT scan taken 3 days after the operation revealed CSF retention with edema along the operative route (Fig. 3A) which disappeared in proportion to the im provement in these neurological symptoms. Case 6: A 62-year-old female had a sudden attack of unconsciousness for 10 minutes about 2 weeks prior to admission. Seven days later, she noticed weakness of the right extremities. She also had occa sional headaches. Neurological examination showed Fig. 3 A: Case 5. CT scan 3 days after operation show slight right hemiparesis and hypesthesia in the right ing CSF retention with marked edema in the lower extremity. A CT scan revealed an irregular left temporal lobe. B: Case 7. CT scan 1 month after operation showing severe CSF hyperdense mass with moderate enhancement in the retention in the left temporal lobe. left trigone (Fig. IF). Gray and partially dark red colored, solid and well encapsulated tumor was totally removed. The histological diagnosis was ing. The neurological examination on admission cavernous angioma (Fig.