What to do if i have hypoechoic mass on left lobe thryoid and already had total parathyroidectomy, can this be cancer?

Not necessarily. : A thyroid mass is most often benign. In the work up a blood test is needed to see if there is hyper-function. A nuclear scan of the thyroid will show if it is cold or hot. Hot nodules are benign. Cold nodule are >80% benign. A needle biopsy of a cold nodule is needed to establish the diagnosis. Most often these are colloid nodules or thyroid cyst. Risk of cancer varies from 5-15%