Spontaneous rodent nervous system tumors, in comparison to those of man, are less well differentiated. Among the central nervous system (CNS) tumors, the "embryonic" forms (medulloblastoma, pineoblastoma) occur both in rodents and humans, whereas the human "adult" forms (gliomas, ependymomas, meningiomas) have fewer counterparts in rodents. In general, the incidence of spontaneous CNS tumors is higher in rats (>1%) than in mice (>0.001%). A characteristic rat CNS tumor is the granular cell tumor. Usually it is associated with the meninges, and most meningeal tumors in rats seem to be totally or at least partly composed of granular cells, which have eosinophilic granular cytoplasm, are periodic acid-Schiff reaction (PAS)-positive, and contain lysosomes. Such tumors are frequently found on the cerebellar surface or at the brain basis. Rat astrocytomas are diffuse, frequently multifocal, and they invade perivascular spaces and meninges. The neoplastic cells with round to oval nuclei and indistinct cytoplasm grow around preexisting neurons, producing satellitosis. In large tumors, there are necrotic areas surrounded by palisading cells. Extensive damage of brain tissue is associated with the presence of scavenger cells that react positively with histiocytic/macrophage markers. The neoplastic astrocytes do not stain positively for glial fibrillary acidic protein; they probably represent an immature phenotype. In contrast to neoplastic oligodendroglia, they bind the lectin RCA-1. Astrocytomas are frequently located in the brain stem, especially the basal ganglia. Rat oligodendroglial tumors are well circumscribed and frequently grow in the walls of brain ventricles. Their cells have water-clear cytoplasm and round, dark-staining nuclei. Atypical vascular endothelial proliferation occurs, especially at the tumor periphery. Occasionally in the oligodendrogliomas, primitive glial elements with large nuclei occur in the form of cell groups that form rows and circles. Primitive neuroectodermal tumors of rats, such as pineal tumors or medulloblastomas, appear to have features similar to those found in man. In mice, the meningeal tumors are mostly devoid of granular cells and the astrocytomas are similar to those occurring in rats, whereas spontaneous oligodendrogliomas are observed extremely rarely. Tumorlike lesions, such as lipomatous hamartomas or epidermoid cysts, are occasionally encountered in the mouse CNS. It is suggested that we classify rodent CNS lesions as "low grade" and "high grade" rather than as "benign" and "malignant." The size of CNS tumors is generally related to their malignancy. Tumors of the peripheral nervous system are schwannomas and neurofibromas or neurofibrosarcomas consisting of Schwann cells, fibroblasts, and perineural cells. Well-differentiated schwannomas are characterized by S-100 positivity and the presence of basement membrane. They show either Antoni A pattern with fusiform palisading cells or Antoni B pattern, which is sparsely cellular and has a clear matrix. The rat develops specific forms of schwannomas in the areas of the submandibular salivary gland, the external ear, the orbit, and the endocardium. Spontaneous ganglioneuromas occur in the rat adrenal medulla or thyroid gland. Compared to experimentally induced neoplasms, the spontaneous tumors of the rodent nervous system are poor and impractical models of human disease, although they may serve as general indicators of the carcinogenic potential of tested chemicals.
Abbot DP (1982). Malignant schwannoma of the dorsal spinal nerve root in a laboratory rat. Lab Anim16: 265-266.
2.
Adams SW, Crowley AM (1987). Posterior paralysis due to spontaneous oligodendroglioma in the spinal cord of a rat. Lab Anim Sci37: 345-347.
3.
Adkison DL, Sundberg JP (1991). "Lipomatous" hamartomas and choristomas in inbred laboratory mice. Vet Pathol28: 305-312.
4.
Alison RH, Elwell MR, Jokinen MP, Dittrich KL, Boorman GA (1987). Morphology and classification of 96 primary cardiac neoplasms in Fischer 344 rats. Vet Pathol24: 488-494.
5.
Al-Zubaidy AJ , Malinowski W. (1984). Spontaneous pineal body tumours (pinealomas) in Wistar rats: A histological and ultrastructural study . Lab Anim18: 224-229.
6.
Berman JJ, Rice JM, Reddick R. (1980). Endocardial schwannomas in rats. Arch Pathol Lab Med104: 187-191.
7.
Berman JJ, Rice JM, Strandberg J. (1978). Granular cell variants in a rat schwannoma. Evidence of neurogenic origin of granular cell tumor (myoblastoma). Vet Pathol15: 725-731.
8.
Bomhard E. (1992). Frequency of spontaneous tumors in Wistar rats in 30 month studies. Exp Toxicol Pathol44: 381-392.
9.
Bomhard E., Rinke M. (1994). Frequency of spontaneous tumours in Wistar rats in 2-year studies. Exp Toxicol Pathol46: 17-29.
10.
Bots GThAM , Kroes R., Feron VJ (1968). Spontaneous tumors of the brain in rats. A report of 3 cases. Pathol Vet5: 290-296.
11.
Botts S., Capen CC, DeLellis RA, Deschl U., Hartig F., Karbe E., Konishi Y., Krinke GJ, Landes Ch, Mettler F., Rebel W., Riley Mgi, Tuch K., Urwyler H. (1994). Endocrine system. In: International Classification of Rodent Tumors. Part I: The Rat, Mohr U (ed). IARC Scientific Publication No 122, Lyon, France, pp 1-75.
12.
Brander P., Perentes E. (1995). Intracranial lipoma in a laboratory rat. Vet Pathol32: 65-67.
13.
Burek JD, van Zwieten MJ, Solleveld HA (1983). Pinealoma, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Endocrine System, Jones TC, Mohr U, Hunt RD (eds). Springer-Verlag, Berlin, pp 350-354.
14.
Cardesa A., Carlton WW, Dungworth DL, Enomoto M., Halm S., Koestner A., Krinke GJ, Render JA, Rittinghausen S., Ruben Z., Solleveld H., Turusov VS, Weisse I., Yoshitomi K. (1994). Central nervous system: heart; eye; mesothelium . In: International Classification of Rodent Tumors. Part I: The Rat, Mohr U (ed). IARC Scientific Publication No 122, Lyon, France, pp 1-80.
15.
Cardesa A., Ribalta T., Vogeley KT, Reifenberger G., Wechsler W., Turusov VS (1990). Tumours of the peripheral nervous system. In: Pathology of Tumors in Laboratory Animals, Vol I, Tumours of the Rat, Turusov VS, Mohr U (eds). IARC Scientific Publication No 99, Lyon, France, pp 699-724.
16.
Carlton WW, Ernst H., Faccini JM, Greaves P., Krinke GJ, Long PH, Maekawa A., Newsholme SJ, Weisse G. (1992). Soft tissue and musculoskeletal system. In: International Classification of Rodent Tumors. Part I: The Rat , Mohr U (ed). IARC Scientific Publication No 122, Lyon, France, pp 1-62.
17.
Carlton WW, Gries ChL (1983). Craniopharyngioma, pituitary gland, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Endocrine System . Jones TC, Mohr U, Hunt RD (eds). Springer-Verlag, Berlin, pp 149-153.
18.
Carlton WW, Gries ChL (1983). Pituicytoma, neurohypophysis, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Endocrine System, Jones TC, Mohr U, Hunt RD (eds). Springer-Verlag, Berlin, pp 156-160.
19.
Carlton WW, Gries ChL (1996). Craniopharyngioma, pituitary gland, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Endocrine System , 2nd ed, Jones TC, Capen CC, Mohr U (eds). Springer-Verlag, Berlin, pp 86-90.
20.
Carlton WW, Gries ChL (1996). Pituicytoma, neurohypophysis, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Endocrine System , 2nd ed, Jones TC, Capen CC, Mohr U (eds). Springer-Verlag, Berlin, pp 94-97.
21.
Chandra M., Riley Mgi, Johnson DE (1992). Spontaneous neoplasms in aged Sprague-Dawley rats . Arch Toxicol66: 496-502.
22.
Crissman JW (1996). Ganglioneuroma, thyroid gland, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Endocrine System , 2nd ed, Jones TC, Capen CC, Mohr U (eds). Springer-Verlag, Berlin, pp 280-286.
23.
Dagle GE, Zwicker GM, Renne RA (1979). Morphology of spontaneous brain tumors in the rat. Vet Pathol16: 318-324.
24.
Fitzgerald JE, Schardein JL, Kurtz SM (1974). Spontaneous tumors of the nervous system in albino rats. J Natl Cancer Inst52: 265-273.
25.
Fraser H. (1986). Brain tumours in mice, with particular reference to astrocytoma. Food Chem Toxicol24: 105-111.
26.
Frith CH, Chandra M. (1990). Spontaneous primary astrocytoma in the spinal cord of a mouse and a rat. Toxicol Pathol18: 427-429.
27.
Garman RH (1988). Malignant reticulosis, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Nervous System, Jones TC, Mohr U, Hunt RD (eds). Springer-Verlag, Berlin, pp 117-123.
28.
Gough AW, Hanna W., Barsoum NJ, Moore J., Sturges JM (1986). Morphologic and immunohistochemical features of two spontaneous peripheral nerve tumors in Wistar rats. Vet Pathol23: 68-73.
29.
Hall LB, Yoshitomi K., Boorman GA (1987). Pathologic features of abdominal and thoracic paragangliomas in F344/N rats. Vet Pathol24: 315-322.
30.
Hamlin HM II, Banas DA (1990). Adrenal gland. In: Pathology of the Fischer Rat, Boorman GA, Eustis SL, Elwell MR, Montgomery CA Jr, MacKenzie WF (eds). Academic Press, San Diego, California, pp 501-518.
31.
Haseman JK, Eustis SL, Arnold J. (1990). Tumor incidences in Fischer 344 rats: NTP historical data. In: Pathology of the Fischer Rat, Boorman GA, Eustis SL, Elwell MR, Montgomery CA Jr, MacKenzie WF (eds). Academic Press, San Diego, California, pp 555-564.
32.
Haseman JK, Hailey JR, Morris RW (1998). Spontaneous neoplasm incidences in Fischer 344 rats and B6C3F1 mice in two-year carcinogenicity studies: A National Toxicology Program update. Toxicol Pathol26: 428-441.
33.
Heath JE (1996). Gangliocytoma, pituitary gland, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Endocrine System , 2nd ed, Jones TC, Capen CC, Mohr U (eds). Springer-Verlag, Berlin, pp 98-101.
34.
Heath JE, Winokur TS (1998). Case report: Pineocytoma in a male Fischer 344 rat. Toxicol Pathol26: 294-297.
35.
Heider K. (1986). Spontaneous craniopharyngioma in a mouse. Vet Pathol23: 522-523.
36.
Hoch-Ligeti C., Restrepo C., Stewart HL (1986). Comparative pathology of cardiac neoplasms in humans and in laboratory rodents: A review. J Natl Cancer Inst76: 127-142.
37.
Hollander CF , Burek JD, Boorman GA, Snell KC, Laquerer GL (1976). Granular cell tumors of the central nervous system of rats. Arch Pathol Lab Med100: 445-447.
38.
Innes Jrm, Borner G. (1961). Tumors of the central nervous system of rats: With report of two tumors of the spinal cord and comments on posterior paralysis . J Natl Cancer Inst26: 719-735.
39.
Ivankovic S. (1976). Tumours of the heart. In: Pathology of Tumours in Laboratory Animals, Vol I, Tumours of the Rat, Turusov VS (ed). IARC Scientific Publication No 6, Lyon, France, pp 313-319.
40.
Jänisch W. (1990). Tumours of the central nervous system. In: Pathology of Tumors in Laboratory Animals, Vol I, Tumours of the Rat, Turusov VS, Mohr U (eds). IARC Scientific Publication No 99, Lyon, France, pp 677-698.
41.
Kitamura T. , Nakanishi K., Watanabe S., Endo Y., Fujita S. (1987). GFA-protein gene expression on the astroglia in cow and rat brains. Brain Res423: 189-195.
42.
Kleihues P., Cavenee WK (1997). Pathology and Genetics of Tumors of the Nervous System. IARC, Lyon, France, 255 pp.
43.
Koestner A., Solleveld HA (1996). Tumors of the pineal gland, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Endocrine System, 2nd ed, Jones JC, Capen CC, Mohr U (eds). Springer-Verlag, Berlin, pp 205-213.
44.
Krinke GJ (1996). Nonneoplastic and neoplastic changes in the peripheral nervous system. In: Pathobiology of the Aging Mouse, Vol 2, Mohr U, Dungworth DL, Capen CC, Carlton WW, Sundberg JP, Ward JM (eds). ILSI Press, Washington, DC, pp 83-93.
45.
Krinke GJ, Germer M. (1993). Binding of lectin ricinus communis agglutinin-1 (RCA-1) to rat brain tumors. Vet Pathol30: 300-303.
46.
Krinke GJ, Kaufmann W. (1996). Neoplasms of the central nervous system. In: Pathobiology of the Aging Mouse, Vol 2, Mohr U, Dungworth DL, Capen CC, Carlton WW, Sundberg JP, Ward JM (eds). ILSI Press, Washington, DC, pp 69-81.
47.
Krinke G., Naylor DC, Schmid S., Froehlich E., Schnider K. (1985). The incidence of naturally-occurring primary brain tumors in the laboratory rat. J Comp Pathol95: 175-192.
48.
Kulwich BA (1994). Epidermoid cysts in the central nervous system of rats and mice: An incidental finding in toxicity/oncogenicity studies. Vet Pathol31: 475-478.
49.
Landes CH, Ruefenacht HJ, Naylor DC, Krinke GJ (1988). Rat endomyocardial disease: A neural origin?Exp Pathol34: 65-69.
50.
Landes CH, Heider K., Krinke AL, Krinke GJ, Mahrous AT, Hess R. ( 1990). Contribution of immunohistochemistry toward the diagnosis of tumors of laboratory rats. Exp Pathol40: 239-250.
51.
Levine S. (1966). Epidermoid cysts of the spinal cord: A spontaneous disease of rats. J Neuropathol Exp Neurol25: 498-504.
52.
MacKenzie WF , Alison RH (1990). Heart. In: Pathology of the Fischer Rat, Boorman GA, Eustis SL, Elwell MR, Montgomery CA Jr, MacKenzie WF (eds). Academic Press, San Diego, California, pp 461-472.
53.
Maekawa A., Mitsumori K. (1990). Spontaneous occurrence and chemical induction of neurogenic tumors in rats—Influence of host factors and specificity of chemical structure. Crit Rev Toxicol20: 287-310.
54.
Maekawa A., Onodera H., Tanigawa H., Furuta K., Takahashi M., Kurokawa Y., Kokubo T., Toshiaki O., Uchida O., Kobayashi K., Hayashi Y. (1984). Spontaneous tumors of the nervous system and associated organs and/or tissues in rats. Gann75: 784-791.
55.
Mawdesley-Thomas LE, Newman AJ (1974). Some observations on spontaneously occurring tumours of the central nervous system of Sprague-Dawley derived rats. J Pathol112: 107-116.
56.
McMartin DN, Sahota P., Gunson DE, Han Hsu H., Spaet RH (1992). Neoplasms and related proliferative lesions in control Sprague-Dawley rats from carcinogenicity studies. Historical data and diagnostic considerations. Toxicol Pathol20: 212-225.
57.
Mennel HD, Zülch E. (1976). Tumours of the central and peripheral nervous systems. In: Pathology of Tumours in Laboratory Animals, Vol I, Tumours of the Rat, Turusov VS (ed). IARC Scientific Publication No 6, Lyon, France, pp 295-312.
58.
Miller JL, Westwood FR, Jackson DG (1992). Neuromyoblastoma in the rat. J Comp Pathol106: 439-443.
59.
Mitsumori K., Boorman GA (1990). Spinal cord and peripheral nerves. In: Pathology of the Fischer Rat, Boorman GA, Eustis SL, Elwell MR, Montgomery CA Jr, MacKenzie WF (eds). Academic Press, San Diego, California, pp 179-191.
60.
Mitsumori K. , Dittrich KL, Stefanski S., Talley FA, Maronpot RR (1987). Immunohistochemical and electron microscopic study of meningeal granular cell tumors in rats. Vet Pathol24: 356-359.
61.
Mitsumori K. , Maronpot RR, GA Boorman (1987). Spontaneous tumors of the meninges in rats. Vet Pathol24: 50-58.
62.
Mitsumori K. , Stefanski S., Maronpot RR (1988). Benign and malignant neoplasms, meninges, rat . In: ILSI Monographs on Pathology of Laboratory Animals. Nervous System, Jones TC, Mohr U, Hunt Rd (eds). Springer-Verlag , Berlin, pp 108-117.
63.
Morgan KT, Alison RH (1988). Gliomas, mouse. In: ILSI Monographs on Pathology of Laboratory Animals. Nervous System, Jones TC, Mohr U, Hunt RD (eds). Springer-Verlag, Berlin, pp 123-129.
64.
Morgan KT, Frith ChH, Swenberg JA, McGrath JT, Zülch KJ, Crowder DM (1984). A morphologic classification of brain tumors found in several strains of mice. J Natl Cancer Inst72: 151-160.
65.
Morgan KT, Sheldon WG (1988). Lipoma, brain, mouse. In: ILSI Monographs on Pathology of Laboratory Animals. Nervous System, Jones TC, Mohr U, Hunt RD (eds). Springer-Verlag, Berlin, pp 130-134.
66.
Nakagawa Y. , Perentes E., Rubinstein LJ (1986). Immunohistochemical characterization of oligodendrogliomas: An analysis of multiple markers. Acta Neuropathol (Berl ) 72: 15-22.
67.
Newman AJ, Mawdesley-Thomas LE (1974). Spontaneous tumours of the central nervous system of laboratory rats. J Comp Pathol84: 39-50.
68.
Novilla MN, Sandusky GE, Hoover DM, Ray SE, Wightman KA (1991). A retrospective survey of endocardial proliferative lesions in rats. Vet Pathol28: 156-165.
69.
Pace V. (1998). Spontaneous choroid plexus carcinoma in an albino rat. Exp Toxicol Pathol50: 225-228.
70.
Pace V., Heider K., Persohn E., Schaetti Ph (1997). Spontaneous malignant craniopharyngioma in an albino rat. Vet Pathol34: 146-149.
71.
Perentes E. , Maraziotis T., Qureshi SR (1991). Granular cell brain tumors of the laboratory rat: An immunohistochemical approach . Acta Neuropathol (Berl) 82: 112-117.
72.
Reindel J., Bobrowski W., Gough A., Anderson J. (1996). Malignant intracranial teratoma in a juvenile Wistar rat. Vet Pathol33: 462-465.
73.
Reznik G., Germann PG (1996). Ganglioneuroma, adrenal, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Endocrine System, 2nd ed, Jones TC, Capen CC, Mohr U (eds). Springer-Verlag, Berlin, pp 427-432.
74.
Reznik G., Germann PG (1996). Neuroblastoma, adrenal gland, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Endocrine System , 2nd ed, Jones TC, Capen CC, Mohr U (eds). Springer-Verlag, Berlin, pp 433-435.
75.
Reznik G., Ward JM ( 1983). Ganglioneuroma, adrenal, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Endocrine System, Jones TC, Mohr U, Hunt RD (eds). Springer-Verlag, Berlin, pp 30-34.
76.
Reznik G., Ward JM ( 1983). Neuroblastoma, adrenal gland, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Endocrine System, Jones TC, Mohr U, Hunt RD (eds). Springer-Verlag, Berlin, pp 35-37.
77.
Rice JM, Ward JM ( 1988). Cardiac neurilemmoma, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Nervous System, Jones TC, Mohr U, Hunt RD (eds). Springer-Verlag, Berlin, pp 165-169.
78.
Schaetti Ph , Argentino-Storino A., Heinrichs M., Mirea D., Popp A., Karbe E. (1995). Aberrant craniopharyngial structures within the neurohypophysis of rats. Exp Toxicol Pathol47: 129-137.
79.
Schwechheimer K., Wiedenmann B., Franke WW (1987). Synaptophysin: A reliable marker for medulloblastomas. Virchows Arch A 411: 53-59.
80.
Skavlen PA, Firminger HI, Breslin PA (1989). Diagnostic exercise: Paralysis in a Long-Evans rat. Lab Anim Sci39: 69-70.
81.
Solleveld HA , Boorman GA (1990). Brain. In: Pathology of the Fischer Rat, Boorman GA, Eustis SL, Elwell MR, Montgomery CA Jr, MacKenzie WF (eds). Academic Press, San Diego, California, pp 155-177.
82.
Solleveld HA , Gorgacz EJ, Koestner A. (1991). Central nervous system neoplasms in the rat. In: Guides for Toxicologic Pathology, STP/ARP/AFIP , Washington, DC, pp 1-17.
83.
Solleveld HA , Zurcher Ch (1994). Neoplasms of the nervous system. In: Pathobiology of the Aging Rat, Vol 2, Mohr U, Dungworth DL, Capen CC (eds). ILSI Press, Washington, DC, pp 55-63.
84.
Stewart HL, Deringer MK, Dunn TB, Snell KC (1974). Malignant schwannomas of nerve roots, uterus and epididymis in mice. J Natl Cancer Inst53: 1749-1758.
85.
Sumi N., Stavrou D., Frohberg H., Jochmann G. (1976). The incidence of spontaneous tumors of the central nervous system of Wistar rats. Arch Toxicol35: 1-13.
86.
Swaen Gjv, Becker AE (1968). Granular cell myoblastoma of the pituitary gland in an old rat: A case report. Lab Anim2: 41-43.
87.
Swenberg JA (1982). Neoplasms of the nervous system. In: The Mouse in Biomedical Research, Vol 4, Foster HL, Small JD, Fox JG (eds). Academic Press, New York, pp 529-536.
88.
Takahashi K. (1981). Studies of experimental oligodendroglioma with special reference to the ultrastructure and immunohistochemical localization of S-100 protein, GFA protein and galactocerebroside. Brain Nerve33: 703-714.
89.
Turusov VS, Ivankovic S. (1990). Tumours of the heart. In: Pathology of Tumors in Laboratory Animals, Vol I, Tumours of the Rat, Turusov VS, Mohr U (eds). IARC Scientific Publication No 99, Lyon, France, pp 725-739.
90.
Walker DM, Walker VE, Hardisty JF, Morgan KT, Swenberg JA (1988). Peripheral nerve sheath tumors, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Nervous System , Jones TC, Mohr U, Hunt RD (eds). Springer-Verlag, Berlin, pp 143-154.
91.
Walker VE, Morgan KT, Zimmerman HM, Innes Jrm (1994). Tumours of the central and peripheral nervous system. In: Pathology of Tumours in Laboratory Animals, Vol 2, Tumours of the Mouse, Turusov V, Mohr U (eds). IARC Scientific Publication No 111, Lyon, France, pp 731-752.
92.
Walker VE, Swenberg JA (1988). Gliomas, rat. In: ILSI Monographs on Pathology of Laboratory Animals. Nervous System, Jones TC, Mohr U, Hunt RD (eds). Springer-Verlag, Berlin, pp 134-143.
93.
Walsh KM, Poteracki J. (1994). Spontaneous neoplasms in control Wistar rats. Fundam Appl Toxicol22: 65-72.
94.
Ward JM, Goodman DG, Squire RA, Chu KC, Linhart MS (1979). Neoplastic and nonneoplastic lesions in aging (C57BL/6N X C3H/ HeN)F1 (B6C3F1) mice. J Natl Cancer Inst63: 849-854.
95.
Ward JM, Rice JM ( 1982). Naturally occurring and chemically induced brain tumors of rats and mice in carcinogenesis bioassays. Ann NY Acad Sci381: 304-319.
96.
Wyand DS, Zwicker GM, Pavkov K. (1987). Spontaneous glioblastoma multiforme in a Charles River CD rat. Toxicol Pathol15: 474-478.
97.
Yamamoto O. , Mitsumori K., Yoshida T., Maita K., Shirasu Y. (1991). Spontaneous malignant pineocytoma in a female Wistar rat. J Vet Med Sci53: 527-529.
98.
Yoshida T., Mitsumori K., Harada T., Maita K. (1997). Morphological and ultrastructural study of the histogenesis of meningeal granular cell tumors in rats. Toxicol Pathol25: 211-216.
99.
Yoshitomi K. , Boorman GA (1991). Intraocular and orbital malignant schwannomas in F344 rats. Vet Pathol28: 457-466.
100.
Yoshitomi K., Brown R. (1990). Ear and pinna. In: Pathology of the Fischer Rat, Boorman GA, Eustis SL, Elwell MR, Montgomery CA Jr, MacKenzie WF (eds). Academic Press, San Diego, California, pp 227-238.
101.
Zimmerman HM , Innes Jrm (1979) Tumors of the central and peripheral nervous system . In: Pathology of Tumours in Laboratory Animals, Vol II, Tumours of the Mouse, Turusov VS (ed). IARC Scientific Publication No 23, Lyon, France, pp 629-654.
102.
Zook BC, Simmens SJ, Jones RV (2000). Evaluation of ENU-induced gliomas in rats: Nomenclature, immunochemistry and malignancy. Toxicol Pathol28: 193-201 (this issue).
