There is an undocumented textscan() parameter 'headercolumns' to indicate the number of leading columns on the line to skip. Note for this purpose that "column" is determined using the same criteria used to determine "column" for the rest of textscan().
Possibly this HeaderColumns setting is only implemented if you use the undocumented format string '' (the empty string) which only works when all of the (unskipped) columns are numeric.
HL = 3; %for example
HC = 10; %in your case
result = textscan(fid, '', 'HeaderLines', HL, 'HeaderColumns', HC, 'Delimiter', ',');
If you want more control over your columns or do not like using undocumented parameters, then use an explicit format that throws away the unwanted data:
HL = 3; %for example
HC = 10; %in your case
NF = 1000; %1000 desired fields
lineformat = [repmat('%*s',1,HC) repmat('%f',1,NF)];
result = textscan(fid, lineformat, 'HeaderLines', HL, 'Delimiter', ',');
