Spontaneous and ethyl-nitrosourea-induced medullomyoblastomas in cerebellar vermis defect (CVD) mutant rats.
A 26-week-old female cerebellar vermis defect (CVD) rat, a mutant with cerebellar vermis defect and cerebellar dysplasia, developed a brain tumor about 10 mm in diameter. Histopathologically, the tumor consisted of diffuse proliferation of small round to ovoid cells with hyperchromatic nuclei, occasionally containing round to strap-shaped myoblastic cells. Immunohistochemically, the small round cells expressed neuron-specific enolase and synaptophysin, indicating neuronal differentiation; myoblastic components reacted to desmin, myoglobin, and vimentin. Based on these findings, the case was diagnosed as a medullomyoblastoma (MMB). Furthermore, two cerebella tumors in CVD rats, which were induced by transplacental application of ethyl-nitrosourea, showed histopathology similar to the aforementioned case. MMB is a very rare tumor in humans and animals; thus, it is noteworthy that MMBs developed in CVD rats, involving the dysplastic cerebellum with abnormal migration of external granule cells.
Kuwamura
M
M
Department of Veterinary Pathology, College of Agriculture, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan. kuwamura@vet.osakafu-u.ac.jp
Shirota
A
A
Takada
A
A
Yamate
J
J
Kotani
T
T
Sakuma
S
S
D000818:Animals; D002528:Cerebellar Neoplasms / Q000473:pathology*; D002531:Cerebellum / Q000187:drug effects / Q000473:pathology* / Q000648:ultrastructure; D005038:Ethylnitrosourea / Q000494:pharmacology*; D005260:Female; D008527:Medulloblastoma / Q000473:pathology*; D008854:Microscopy, Electron; D051381:Rats; D011917:Rats, Inbred Lew; D011922:Rats, Mutant Strains
D005038:Ethylnitrosourea