thyroid cyst

I began with loss of use of two fingers and thumb, and examination revealed wasting of all forearm muscles.MRI scan and echo have shown a 2.5 cm cyst in the thyroid partly solid. How likely is it, that this is malignant, and the cause of my symptoms?

[Crochetya]

No one, not even your Dr. can diagnose this without a biopsy. You want an answer with out enough facts or factual information. 50/50. Depending on your family history. Just my thoughts only.,  Do not quote me. I would definitely ask my Endo about a biopsy and the chance of cancer.

[Smilerdeb]

Are you a Diabetic?
And have you been tested for Rheumatoid Arthritis?
This is one of the classic symptoms for muscle wastage.
We really need more info on what test results you have and any diagnosis of health issues.
The thyroid cyst would have no bearing of muscle wastage in the hand and fingers.
I doubt that wouldve caused the nodule.
You may have an Autoimmune Disease and RA is another one.
Get tested for Rheumatoid Arthritis or Fibromyalgia.
This is not to say you have it but at least it would rule it out.
Both these can be tested via blood tests.