The major clinical symptom of metastatic<unk><unk>  carcinoma is diarrhea; occasionally a patient will have flushing episodes. Both occur particularly with liver metastasis, and either symptom may be the first manifestation of the disease. The flushing that occurs in<unk><unk>  carcinoma is indistinguishable from that associated with carcinoid syndrome. In<unk> , the flushing, diarrhea, and itching (pruritus) are all caused by elevated levels of calcitonin gene products (calcitonin or calcitonin gene-related peptide). By comparison, the flushing and diarrhea observed in carcinoid syndrome is caused by elevated levels of circulating serotonin.<unk><unk>  carcinoma may also produce a<unk>  nodule and enlarged cervical lymph nodes. Sites of spread of<unk><unk>  carcinoma include local lymph nodes in the neck, lymph nodes in the central portion of the chest (mediastinum), liver, lung, and bone. Spread to other sites such as skin or brain occurs but is uncommon.
Medullary thyroid cancer
Papillary thyroid cancer
Follicular thyroid cancer
Thyroid lymphoma
Thyroid adenoma
Anaplastic thyroid cancer
Thyroid cancer
Squamous-cell thyroid carcinoma