2 cm Exophytic Kidney Mass - 44 year old Male

[walleyek]

Hello.  My medical people are sometimes frustrating to deal with.  Just getting an appointment can take 2 weeks!  I had a CT scan done on 12-30-08 for severe constipation.  The CT scan said "Abnormal CT scan, which suggests a mass vs. cyst off the left kidney."   I then went in for a kidney ultrasound and it came back with "The lesion in question does not appear to be a simple cyst based on ultrasound criteria.  There is a 2 cm exophytic mass off the lower pole.  Interval MRI could be performed."  

From my research most of these types of kidney masses are malignant, correct?  Why would I wait for an "interval MRI"?    Would an MRI show the docs exactly what type of cell we're dealing with here?

I'm scared and don't want to lose a kidney.  Should I be on the lookout for any other symptoms?  One strange thing is that for about the last month I've had a very noticeable metallic taste in my mouth.  Could this be related to kidney cancer?  Could the mass be from another cancer that has mestatisized?  I'm sort of concerned.

Thanks for your help!