Cyst on Spleen

I have been diagnosed with cysts in my left kidney and one on my spleen.  I am being followed every year with CT scan for these. However, the cyst on my spleen has increased in size from 1cm to 41/2cm in the past two years.  I am just told that it is a cyst after the CT scan, but am concerned with the fact that the cyst is changing in size.  Should I be concerned of the change?  The cysts that are in my kidneys have stayed the same for and therefore does't necessarily cause me concern.  How large can cyst become before causing problems?  Since the spleen is very vascular, am I in danger of the cyst rupturing?  How would we know the cyst is not in danger of becoming malignat?

[Chuck]

cyst do not become malignat. Have you been checked for polycystic kidneys? This is potentially life threatening as you become older.not to worry you, but this should be checked. Good Luck.