88
Double intracranial tumours ofmaldevelopmental origin teratoma at the pineal region and an epide r moid cyst in the fourth ventr icle T Yamaki. M. Takeda. H. Takayama. Y. Nakaga ki Departrnent of Neuro surgery . Sunagawa City Medical Cente r. Sunagawa. Hokkaido . Ja pa n
A 21-year-old man with douh le intracranial tumours of ma ldevelopmental origin , ter atom a at the pineal region and an epidermoid cyst in the fourth ventricle, is reported . Th e tumours wer e rem oved totally hy multiple operations; the epidermoid cyst was resected hy suhoccipital craniectomy with the patient in prone position and th e teratoma was removed via occipital transtentorial approach with the pati en t in sitting position. Maldevelopm ental tumours located with in the cranial cavity with different histological types such as the present case ha ve not so rar been described. Histogen esis of these tumours is confusing because terato ma orten conta ins tissue s of epidermoid cyst. Etiological considerations for these tumours are presented and appropriate operative pro cedures for tumours sirnultaneously occurring in th e pineal and the fourth ventricle are also discussed . Doppe lte int rakranielle Tu moren a ufgrund von Mißhildungen - Te ratom im Zirhe ldrüsenbereich und Epidermoid-Zysle im vierten Ventr ike l Es wird über den Fall eines 21jährigen männlichen Patienten mit zwei intrakraniellen Tumoren dysont ogenetischen Urs prungs. einem Teratom im pinealen Bereich und einer epidermoiden Zyste im vierten Ventrikel berichtet. Die Tum ore wurden in mehreren Operationen vollständig entfern t. Die Epidermoid-Zyste wur de durch subokzipital e Kraniektomi e in Bauchlage reseziert und das Teratom durch okzipitale transtentoriellen Zugang beim sitzenden Patient en entfern t. Intrakranielle dysontogenetische Tumore mit schwieriger Histogenese wie im vorliegenden Fall wur den bislan g noch nicht beschrieben . Die Histogen ese dieser Tum ore war verwirre nd, da Terat ome häufig Gewebe von epidermoiden Zysten entha lten. Der Bericht geht auf die ätiologische n Überlegungen zu diesen Tumoren ein und bespricht auch die für gleichz eitig in der Zirbeldrüse und der vierten Ventrike l vorkommende Tumore geeigneten operativen Verfahren .
Teratomas are usuall y composed of various tissues representing all classic germ layers. Therefore the y are rega rded as the outcome of pervert ed developm ent in emb ryogenes is (11). A1though tum ours of maldevelopme ntal origio such as derm aid and epidermoid cysts might be included in the category of ter atomas, they are not included in tru e neoplasms as teratom as constituting different clinical entities in the centra l nervau s system (2). Tbe pr esent case showed simultaneo us occurrence of teratoma and an epidermoid cyst situated in the median plan e in different intracrani al compartme nts. Histogen esis of th ese tumours and operative procedures for doubl e tumours located in the pineal region and the fourth ventricl e are discussed . CaseHeport A zt -yea r-old man was admttte d to Sunagawa City Medical Center on July 16. 1984. because of decr eased visual acuity. double vision, retrobulbar pain and nausea. He was in good health until two months earlier when he began to notlce impaired visual acuity with occasional double vislon. In the previous five days. retrobulbär pa in developed followed by na usea a nd vomiting. Neurological examinat ion on adm ission revealed bilateral visual Impairme nt. upward gaze palsy with convergence nystagmus. an d fine horizontal nystagmus on lateral gaze in both directions. Fundoscopic examina tions disclosed moder ate papilledema bilaterall y. Laboratory data wer e an normal. Computer ized Tcm cgraphy (CT) scan (Fig. 1) disclosed moderate enlargement of lateral and thi rd ventricle with a negative density mass (- 26 Hlfl occupying the fourth ventricle and a n irregular density mass situa ted at the pineal region. A small negative density area (-203 HU). which was ccnsider ed to be free fat. was found at the a pex of the fronta l horn ofthe late ral ventricle. Infusion of cont rast material resulted in enhancement of the pineal tumour. No continuity was found between the pineal tumour and the fourth ventr icle mass on CT sca ns. Left verteb ral angiogram revealed only mass effect ofthe tumour . Soon after admission the patient began to feel dizziness followed by worsen ing of retrobulbär pain a nd nausea . Ventriculoperito nea l (VP) shunt was inserted two days after adm ission. Nausea and vomiting reappea red about ten days after the shunt procedu re accom panied by mild consciousn ess disturbance. which deteriorated progressively. On August 5. 1984. removal of both tu mours was atte mpted through suboccipital cra niectomy with the patient in prone position. The tumor in the fourt h ventricle showed typical pearly appearance an d was totally removed. However. we found it difficult to remove the pinea l tumour because the patlent's shoulder
Key-Words Double tum our - Epidermoid cystIntracranial - Teratoma
Neurochirurgia 33 (1990188-90 © GeorgThleme Verlag Stuugart · NewYork
Downloaded by: National University of Singapore. Copyrighted material.
Introduction Su mmary
interfer ed with our approach th rough the supracerebellar space to re ach the pineal regten . Histopathological examination of the fourth ventricle tumour (Fig. 3) revealed simpl e stratified squa mous epith elium with considera ble ker atini zation consiste nt with features of epidermoid cyst. Consciousness disturban ce persisted post oper atively showing somnolence, apallicfacial expre ssion, and inactive body movement. In mid -August, 1984 , resecti on of the pineal tumour was atte mpted via suprace rebella r approach through the sa me craniotomy with the pati ent in sitting position this tim e. Becau se of the long dist ance and restr icted ope rative field in th is appro ach through the su pracerebellar ciste rn , this operatio n resulted in only biopsy of th e tumour . Another trial of tumo ur resection wa s perform ed with the patie nt in the sitting position th rough a n occipital transte ntorial approach. This approac h appeared to be suited for the tumour rem ova l in the present case . The tumo ur was weil defined showi ng grey ish appea rance and was compose d of'tissues of various consistency. The re was no continu ity with the previously resected epidermoid in the fourth ventricle. Histopathologically, the tumo ur was comp osed of multip le foci of matur e cartilage . fatty tissu e. mu cosal epithelium of the digestive tr act and bronchus , a nd neuroectod ermal tissues. whi ch wer e dia gnosed to he teratoma (Fig. 4). Ther eaft er the patien t showe d slow hut steady c1inical improvem ent. The cons ciousness returned to nearly norm al, bu t decrea sed mental acu ity and incoordinatlon of the extre mities rem ain ed requiring partial assistance for his daily Iife. The patient returned home on Aug. 31. 1985.
Neurochirurgia 33 (1990)
Fig. 1 Left: l argelowdensity massoccupiesthe fourthventriclecompressing thesurroundingcerebel lar parenchyma. Middle:Intheuppersectlon oftheCT scan,anoval shapedtumourwith irregular densities located atthe pineal region isdelineated. Right: Intraventricularfreefat ispresent at theapex ofthe anterior horns of the lateral ventricle
Discussion This case is uniqu e in presenting doub le intracranial tumours ofmaldevelopmental origin; teratoma in the pinea l region and an epide rmoid cyst in the fourth ventriele. Although dermoi d and epidermoid cysts ar e often treated separately from teratomas on account of their distinctive growth features (2. 10. 11), they cert ainly share common histological appearance and therefore their close relationship in histo genesi s is considered. Dermoid and epidermoid cysts ar e as sum ed to develop as a result ofinclusion of ectodermal elements at the time of closure of neural groove (11). Epidermoid tumours tend to show lateralized anatominal locations in the cere bellopontine angle or parapituiary regions , therefore they are supposed to be gen erated during the formation of the secondary cere bral vesiele (Tl ), On th e other hand, ther e are various theories concerning the development of teratomas each claiming th at teratomas originate from : 1) primordial germ cells (7, 13); 2) non germinal cells of the early conce ptus, or "embryonic" cells (3. 4); 3) extraembryonic cells (8); 4) conjoined and maldeveloped twins (9). Baxter and Netsky (2) mak e a e1ear distinction between malformative cysts and teratomas on account oftheirdifferent natures of growth. Malformati ve cysts are developmental in origin and are not neoplasm s: th ey enlarge bydesquamation of normal cells and by secretion. Teratomas, however, ar e neoplasrns: th ey grow by progressive mitotic division ofthe cells. The association ofteratoma and an epidermoid cyst th erefore should be cons idered as pure coinciden ce. However, som e authors believe th at dermoid and epidermoid cysts hav e the same developmental origin as teratomas (1 , 6).lf so, simultaneous occurrence of tera toma and epidermoid cyst might be considered as follows whatever the tru e origin of teratomas : 1) th ey ar e of the same origin and the refore multicentri c: 2) the y ar e frorn different origins an d th er efore they ar e coincidental; 3) teratoma is th e primary tumour and epid errnoid is a rnetastati c lesion. It
89
Fig. 2 Histopathological study of thefourthventricletumour showedabundant keratinized materialdesquamated fromthe epidermallayer without the adnexal structures,whichIs consistent withfeatures of anepidermoid cyst. HE x 100
Fig. 3 Thepinealtumourwas composed of various kinds of tissuesincluding cartilage,fattytissue, epithelturn ofthedigestive and bronchial tract. andneura l tlssue, all of which aremature adultcomponents. HE x 40
Downloaded by: National University of Singapore. Copyrighted material.
Double intracranial tlimours ofmalde oelapmen tat origin
/Veurochiru rgia 33 (19 90)
r
was impossible to obta in an y direct evidence to demonstrat e which one is correcl. Hirsh et al. (S) reported a similar case ofa 2-month-old baby with teratoma arising from the pinea! region and an epide rmoid cyst in the thoraeie spinal subarach noid space. The wall ofthe keratinized cyst was lined by squamous epithelium along with a few glands lined by columnar epithelium making the epidermoid cyst most likely a seedling metastasis. Although th ere was no evidence of the epidermoid cyst contai ning other tissue components in this case. this seedling metastasis from teratoma tissue to form an epider moid cyst could possibly occur. Ifth e first two possibilities are to be believed, misplaced multipotential cells are thought to have located in different places in the central nervous system in an ea rly stage of embryogenesis.
Refer ences
The primary treatment for intracranial tera tomas and for malformative cysts is surgical resection. We allempted to remove the pinealtumour from three different surgical approaches: (1) suboccipital cra niotomy with the patient in prone position after the fourth ventricle epidermoid was totally evacuated; (2) infratentorial supracerebellar ap proach with the patient in sitting position; and (3)occipital transtentor ial approach with the patient in sitting position. It was difficult to remove the pineal tum our with the first two approaches hecause of na rrow operati ve fields and rather long distan ce to reach the pineal region. If the pineal tumour had been of small size, the patient positioned more adequately, and if the surgeons had been more experienced with pineal tum ours, hoth of the tumours could have heen removed at th e first opera tion . Sa no's indication (12) could be ap plied in this case : when the tumour occupies the quadri geminal cistern extending above and below the tentorial incisu ra, the hest choice for removal of the pineal tumour is an occipital transtentorial approach with the patient in sitting position. This approach gave a good exposure of the pineal tumour so that we were capa ble of resecting the tumour totally. Ackno wledgeme nts We wish 10 expres s our graütude 10 Prof. Kazuo Hashi of'Depanment ofNeu rosurgery, Sapporo Medical College, for revlewing this ma nuscript an d giving valuable suggestlons.
Yamaki. M. Takeda. H. Takay ama. Y. Nakagaki
Arseni. c., L. Danila. N. Nicoia. M. Georqion. C. lstra ti: Intracranial teratcmas. Acta Neurochir. 20 (1969137-51 (Wien) 2 Boxte t , J. W. M. G. Netzky: Epidennoi d tumou rs and dermeid tumours. Pathology. In: Wilkins and Rengachary (eds.I. Neurosu rgery. McGraw-HiII Co. New York (1985) 655-661 3 Damjanov. l.. D. Solter: Experime ntal teratoma . Curr . Top. Pathol. 59 (974)69-129 .. Diwan. S. B.. L. C. Stevens: Development of teratomas fro m the ectoderm of mouse egg cyllnders. J . Natl. Cancer Inst. 57 (] 9761 93 7-939 5 Hirsn. L. F.. L. B. Borke. H. H. Schmidek: Unusual cause of relapsing hydrocepha lus. Arch. Neruol. 34 (] 977) 505- 507 6 lngraham. F. D., O. T. Bai/ey: Cystic tera tomas and teratoid tumours of the central nervous system in infancy and childhood. J . Neurosurg. 3 (1946) 511-514 7 Mulligan, R. M.: Pathogenesis ofterato id tumours of the ovary and testis. Patho1. Annu. 10 (1975) 271- 298 S Pay ne. J. M.. S. Pay ne: Placental grafts in rats. J. Embryo!. Exp. Morph ol. 9 (196 1) 106- 116 9 Roqers. S. c.: Anencepha lus. spina bifida and teratomas. Br. J. Prev. sec. Med. 30 0976126-28 10 Rubinstein. L. J.: Tumoursofthe central nervous system . In: Atlas of tumour pathology. H. 1.Firminge r Ied.l 2 nd series. Pesetele 6. Washington D. C.. Armed Forces Institute of Pathology. 1972 . pp 285-292 11 Russet. D. S.. L. 1. Rubinstein: Congenita l tumours of maldevelopmenta lorigin: Pathology of the tumours of the centra l nervous syste m. ed .3. Edwa rd Amo ld Ipublisbersl Ud. London 1971, pp 13- t 9 12 Sano. K.: Pineal regten tumours: Problems in pathology an d trea tment. CHn. Neurosurg. 30 (1983) 59-91 13 S teeo ens. L. c.: The biology of tera tomas . Adv. Morphog. 6 (]967) 1- 31 1
Toshiaki Yamaki. M. D. Department ofNeurosurgery Sap poro Medical College. S·1 W· 16 Sapporo/Japan
Downloaded by: National University of Singapore. Copyrighted material.
90
Double intracranial tumours ofmaldevelopmental origin teratoma at the pineal region and an epide r moid cyst in the fourth ventr icle T Yamaki. M. Takeda. H. Takayama. Y. Nakaga ki Departrnent of Neuro surgery . Sunagawa City Medical Cente r. Sunagawa. Hokkaido . Ja pa n
A 21-year-old man with douh le intracranial tumours of ma ldevelopmental origin , ter atom a at the pineal region and an epidermoid cyst in the fourth ventricle, is reported . Th e tumours wer e rem oved totally hy multiple operations; the epidermoid cyst was resected hy suhoccipital craniectomy with the patient in prone position and th e teratoma was removed via occipital transtentorial approach with the pati en t in sitting position. Maldevelopm ental tumours located with in the cranial cavity with different histological types such as the present case ha ve not so rar been described. Histogen esis of these tumours is confusing because terato ma orten conta ins tissue s of epidermoid cyst. Etiological considerations for these tumours are presented and appropriate operative pro cedures for tumours sirnultaneously occurring in th e pineal and the fourth ventricle are also discussed . Doppe lte int rakranielle Tu moren a ufgrund von Mißhildungen - Te ratom im Zirhe ldrüsenbereich und Epidermoid-Zysle im vierten Ventr ike l Es wird über den Fall eines 21jährigen männlichen Patienten mit zwei intrakraniellen Tumoren dysont ogenetischen Urs prungs. einem Teratom im pinealen Bereich und einer epidermoiden Zyste im vierten Ventrikel berichtet. Die Tum ore wurden in mehreren Operationen vollständig entfern t. Die Epidermoid-Zyste wur de durch subokzipital e Kraniektomi e in Bauchlage reseziert und das Teratom durch okzipitale transtentoriellen Zugang beim sitzenden Patient en entfern t. Intrakranielle dysontogenetische Tumore mit schwieriger Histogenese wie im vorliegenden Fall wur den bislan g noch nicht beschrieben . Die Histogen ese dieser Tum ore war verwirre nd, da Terat ome häufig Gewebe von epidermoiden Zysten entha lten. Der Bericht geht auf die ätiologische n Überlegungen zu diesen Tumoren ein und bespricht auch die für gleichz eitig in der Zirbeldrüse und der vierten Ventrike l vorkommende Tumore geeigneten operativen Verfahren .
Teratomas are usuall y composed of various tissues representing all classic germ layers. Therefore the y are rega rded as the outcome of pervert ed developm ent in emb ryogenes is (11). A1though tum ours of maldevelopme ntal origio such as derm aid and epidermoid cysts might be included in the category of ter atomas, they are not included in tru e neoplasms as teratom as constituting different clinical entities in the centra l nervau s system (2). Tbe pr esent case showed simultaneo us occurrence of teratoma and an epidermoid cyst situated in the median plan e in different intracrani al compartme nts. Histogen esis of th ese tumours and operative procedures for doubl e tumours located in the pineal region and the fourth ventricl e are discussed . CaseHeport A zt -yea r-old man was admttte d to Sunagawa City Medical Center on July 16. 1984. because of decr eased visual acuity. double vision, retrobulbar pain and nausea. He was in good health until two months earlier when he began to notlce impaired visual acuity with occasional double vislon. In the previous five days. retrobulbär pa in developed followed by na usea a nd vomiting. Neurological examinat ion on adm ission revealed bilateral visual Impairme nt. upward gaze palsy with convergence nystagmus. an d fine horizontal nystagmus on lateral gaze in both directions. Fundoscopic examina tions disclosed moder ate papilledema bilaterall y. Laboratory data wer e an normal. Computer ized Tcm cgraphy (CT) scan (Fig. 1) disclosed moderate enlargement of lateral and thi rd ventricle with a negative density mass (- 26 Hlfl occupying the fourth ventricle and a n irregular density mass situa ted at the pineal region. A small negative density area (-203 HU). which was ccnsider ed to be free fat. was found at the a pex of the fronta l horn ofthe late ral ventricle. Infusion of cont rast material resulted in enhancement of the pineal tumour. No continuity was found between the pineal tumour and the fourth ventr icle mass on CT sca ns. Left verteb ral angiogram revealed only mass effect ofthe tumour . Soon after admission the patient began to feel dizziness followed by worsen ing of retrobulbär pain a nd nausea . Ventriculoperito nea l (VP) shunt was inserted two days after adm ission. Nausea and vomiting reappea red about ten days after the shunt procedu re accom panied by mild consciousn ess disturbance. which deteriorated progressively. On August 5. 1984. removal of both tu mours was atte mpted through suboccipital cra niectomy with the patient in prone position. The tumor in the fourt h ventricle showed typical pearly appearance an d was totally removed. However. we found it difficult to remove the pinea l tumour because the patlent's shoulder
Key-Words Double tum our - Epidermoid cystIntracranial - Teratoma
Neurochirurgia 33 (1990188-90 © GeorgThleme Verlag Stuugart · NewYork
Downloaded by: National University of Singapore. Copyrighted material.
Introduction Su mmary
interfer ed with our approach th rough the supracerebellar space to re ach the pineal regten . Histopathological examination of the fourth ventricle tumour (Fig. 3) revealed simpl e stratified squa mous epith elium with considera ble ker atini zation consiste nt with features of epidermoid cyst. Consciousness disturban ce persisted post oper atively showing somnolence, apallicfacial expre ssion, and inactive body movement. In mid -August, 1984 , resecti on of the pineal tumour was atte mpted via suprace rebella r approach through the sa me craniotomy with the pati ent in sitting position this tim e. Becau se of the long dist ance and restr icted ope rative field in th is appro ach through the su pracerebellar ciste rn , this operatio n resulted in only biopsy of th e tumour . Another trial of tumo ur resection wa s perform ed with the patie nt in the sitting position th rough a n occipital transte ntorial approach. This approac h appeared to be suited for the tumour rem ova l in the present case . The tumo ur was weil defined showi ng grey ish appea rance and was compose d of'tissues of various consistency. The re was no continu ity with the previously resected epidermoid in the fourth ventricle. Histopathologically, the tumo ur was comp osed of multip le foci of matur e cartilage . fatty tissu e. mu cosal epithelium of the digestive tr act and bronchus , a nd neuroectod ermal tissues. whi ch wer e dia gnosed to he teratoma (Fig. 4). Ther eaft er the patien t showe d slow hut steady c1inical improvem ent. The cons ciousness returned to nearly norm al, bu t decrea sed mental acu ity and incoordinatlon of the extre mities rem ain ed requiring partial assistance for his daily Iife. The patient returned home on Aug. 31. 1985.
Neurochirurgia 33 (1990)
Fig. 1 Left: l argelowdensity massoccupiesthe fourthventriclecompressing thesurroundingcerebel lar parenchyma. Middle:Intheuppersectlon oftheCT scan,anoval shapedtumourwith irregular densities located atthe pineal region isdelineated. Right: Intraventricularfreefat ispresent at theapex ofthe anterior horns of the lateral ventricle
Discussion This case is uniqu e in presenting doub le intracranial tumours ofmaldevelopmental origin; teratoma in the pinea l region and an epide rmoid cyst in the fourth ventriele. Although dermoi d and epidermoid cysts ar e often treated separately from teratomas on account of their distinctive growth features (2. 10. 11), they cert ainly share common histological appearance and therefore their close relationship in histo genesi s is considered. Dermoid and epidermoid cysts ar e as sum ed to develop as a result ofinclusion of ectodermal elements at the time of closure of neural groove (11). Epidermoid tumours tend to show lateralized anatominal locations in the cere bellopontine angle or parapituiary regions , therefore they are supposed to be gen erated during the formation of the secondary cere bral vesiele (Tl ), On th e other hand, ther e are various theories concerning the development of teratomas each claiming th at teratomas originate from : 1) primordial germ cells (7, 13); 2) non germinal cells of the early conce ptus, or "embryonic" cells (3. 4); 3) extraembryonic cells (8); 4) conjoined and maldeveloped twins (9). Baxter and Netsky (2) mak e a e1ear distinction between malformative cysts and teratomas on account oftheirdifferent natures of growth. Malformati ve cysts are developmental in origin and are not neoplasm s: th ey enlarge bydesquamation of normal cells and by secretion. Teratomas, however, ar e neoplasrns: th ey grow by progressive mitotic division ofthe cells. The association ofteratoma and an epidermoid cyst th erefore should be cons idered as pure coinciden ce. However, som e authors believe th at dermoid and epidermoid cysts hav e the same developmental origin as teratomas (1 , 6).lf so, simultaneous occurrence of tera toma and epidermoid cyst might be considered as follows whatever the tru e origin of teratomas : 1) th ey ar e of the same origin and the refore multicentri c: 2) the y ar e frorn different origins an d th er efore they ar e coincidental; 3) teratoma is th e primary tumour and epid errnoid is a rnetastati c lesion. It
89
Fig. 2 Histopathological study of thefourthventricletumour showedabundant keratinized materialdesquamated fromthe epidermallayer without the adnexal structures,whichIs consistent withfeatures of anepidermoid cyst. HE x 100
Fig. 3 Thepinealtumourwas composed of various kinds of tissuesincluding cartilage,fattytissue, epithelturn ofthedigestive and bronchial tract. andneura l tlssue, all of which aremature adultcomponents. HE x 40
Downloaded by: National University of Singapore. Copyrighted material.
Double intracranial tlimours ofmalde oelapmen tat origin
/Veurochiru rgia 33 (19 90)
r
was impossible to obta in an y direct evidence to demonstrat e which one is correcl. Hirsh et al. (S) reported a similar case ofa 2-month-old baby with teratoma arising from the pinea! region and an epide rmoid cyst in the thoraeie spinal subarach noid space. The wall ofthe keratinized cyst was lined by squamous epithelium along with a few glands lined by columnar epithelium making the epidermoid cyst most likely a seedling metastasis. Although th ere was no evidence of the epidermoid cyst contai ning other tissue components in this case. this seedling metastasis from teratoma tissue to form an epider moid cyst could possibly occur. Ifth e first two possibilities are to be believed, misplaced multipotential cells are thought to have located in different places in the central nervous system in an ea rly stage of embryogenesis.
Refer ences
The primary treatment for intracranial tera tomas and for malformative cysts is surgical resection. We allempted to remove the pinealtumour from three different surgical approaches: (1) suboccipital cra niotomy with the patient in prone position after the fourth ventricle epidermoid was totally evacuated; (2) infratentorial supracerebellar ap proach with the patient in sitting position; and (3)occipital transtentor ial approach with the patient in sitting position. It was difficult to remove the pineal tum our with the first two approaches hecause of na rrow operati ve fields and rather long distan ce to reach the pineal region. If the pineal tumour had been of small size, the patient positioned more adequately, and if the surgeons had been more experienced with pineal tum ours, hoth of the tumours could have heen removed at th e first opera tion . Sa no's indication (12) could be ap plied in this case : when the tumour occupies the quadri geminal cistern extending above and below the tentorial incisu ra, the hest choice for removal of the pineal tumour is an occipital transtentorial approach with the patient in sitting position. This approach gave a good exposure of the pineal tumour so that we were capa ble of resecting the tumour totally. Ackno wledgeme nts We wish 10 expres s our graütude 10 Prof. Kazuo Hashi of'Depanment ofNeu rosurgery, Sapporo Medical College, for revlewing this ma nuscript an d giving valuable suggestlons.
Yamaki. M. Takeda. H. Takay ama. Y. Nakagaki
Arseni. c., L. Danila. N. Nicoia. M. Georqion. C. lstra ti: Intracranial teratcmas. Acta Neurochir. 20 (1969137-51 (Wien) 2 Boxte t , J. W. M. G. Netzky: Epidennoi d tumou rs and dermeid tumours. Pathology. In: Wilkins and Rengachary (eds.I. Neurosu rgery. McGraw-HiII Co. New York (1985) 655-661 3 Damjanov. l.. D. Solter: Experime ntal teratoma . Curr . Top. Pathol. 59 (974)69-129 .. Diwan. S. B.. L. C. Stevens: Development of teratomas fro m the ectoderm of mouse egg cyllnders. J . Natl. Cancer Inst. 57 (] 9761 93 7-939 5 Hirsn. L. F.. L. B. Borke. H. H. Schmidek: Unusual cause of relapsing hydrocepha lus. Arch. Neruol. 34 (] 977) 505- 507 6 lngraham. F. D., O. T. Bai/ey: Cystic tera tomas and teratoid tumours of the central nervous system in infancy and childhood. J . Neurosurg. 3 (1946) 511-514 7 Mulligan, R. M.: Pathogenesis ofterato id tumours of the ovary and testis. Patho1. Annu. 10 (1975) 271- 298 S Pay ne. J. M.. S. Pay ne: Placental grafts in rats. J. Embryo!. Exp. Morph ol. 9 (196 1) 106- 116 9 Roqers. S. c.: Anencepha lus. spina bifida and teratomas. Br. J. Prev. sec. Med. 30 0976126-28 10 Rubinstein. L. J.: Tumoursofthe central nervous system . In: Atlas of tumour pathology. H. 1.Firminge r Ied.l 2 nd series. Pesetele 6. Washington D. C.. Armed Forces Institute of Pathology. 1972 . pp 285-292 11 Russet. D. S.. L. 1. Rubinstein: Congenita l tumours of maldevelopmenta lorigin: Pathology of the tumours of the centra l nervous syste m. ed .3. Edwa rd Amo ld Ipublisbersl Ud. London 1971, pp 13- t 9 12 Sano. K.: Pineal regten tumours: Problems in pathology an d trea tment. CHn. Neurosurg. 30 (1983) 59-91 13 S teeo ens. L. c.: The biology of tera tomas . Adv. Morphog. 6 (]967) 1- 31 1
Toshiaki Yamaki. M. D. Department ofNeurosurgery Sap poro Medical College. S·1 W· 16 Sapporo/Japan
Downloaded by: National University of Singapore. Copyrighted material.
90
