.htaccess: Allow only one Folder Structure - 301 Redirect

Question

Hello, how can I allow only one Folder-Structure with .htaccess like that:

http://www.example.com/**dynamicword**+FIXEDWORD1+FIXEDWORD2/

the dynamicword is not fix, anything else is 301:

http://www.example.com/**dynamicword**+FIXEDWORD1+mistype/mistype/ --> 301
http://www.example.com/**dynamicword**+FIXEDWORD1+mistype/mistype --> 301
http://www.example.com/**dynamicword**+FIXEDWORD1+FIXEDWORD2/mistype --> 301

Is that possible?