Actually impossible from the point of view of an import utility:

LOAD DATA [LOW_PRIORITY | CONCURRENT] [LOCAL] INFILE 'file_name.txt'
    [REPLACE | IGNORE]
    INTO TABLE tbl_name
    [FIELDS
        [TERMINATED BY '\t']
        [[OPTIONALLY] ENCLOSED BY '']
        [ESCAPED BY '\\' ]
    ]
    [LINES 
        [STARTING BY '']    
        [TERMINATED BY '\n']
    ]
    [IGNORE number LINES]
    [(col_name,...)]
[download]

Embedded newlines make it hard to define what represents a 'row'. Fortunately AFAIK you can't insert newlines into an Excel cell string as it triggers moving you to a new cell.