select
   u.name,
   o.name,
   case (o.type) when 'S' then 'SYSTEM TABLE' else 'TABLE' end,
   (select convert(varchar(8000), value) from ::fn_listextendedproperty(NULL, 'user', u.name, 'table', o.name, null, null) where name = 'MS_Description') as coln
from
   sys.sysobjects o
   join sys.schemas  u on (u.schema_id = o.uid)
where
   o.type in ('U', 'S')
   and u.name = "something here"
order by 1, 2

SQLSTATE = 42000, Microsoft SQL Native Client, Incorrect Syntax near ‘u’

select
   u.name,
   o.name,
   case (o.type) when 'S' then 'SYSTEM TABLE' else 'TABLE' end,
   convert(varchar(8000), ex.value) as coln
from
   [%CATALOG%.]sys.sysobjects o
   join [%CATALOG%.]sys.schemas  u on (u.schema_id = o.uid)
   cross apply ::fn_listextendedproperty(NULL, 'user', u.name, 'table', o.name, null, null) ex
where
   o.type in ('U', 'S')
[  and u.name = %.q:OWNER%]
and ex.name = 'MS_Description'
order by 1, 2

[  and u.name = %.q:OWNER%]