You need to get further workup for Medullary
thyroid carcinoma(MTC), with serum calcitonin level, and get tested for few other hormonal abnormalities conditions(pheo) can coexist with MTC.
For MTC, you need to undergo surgery for removal of thyroid gland +/- appropriate lymph nodes of neck.
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Next Steps
Please consult in person with me / any good head and neck oncosurgeon in your place for complete workup and management