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Several types of thyroid cancer that distinguish themselves by the histology exist. It is necessary to oppose the differentiated cancers that hormonodépendants is and sensitive in the TSH (Thyrostimuline: hormone produced by the hypophysis to stimulate the production of thyroxine by the thyroid gland) and the undifferentiated and medullary cancers that are independent of the TSH. As for most cancers, their precise reason is unknown.
 ..Thyroid cancer: The signs of the illness
a) differentiated Cancer (papillaire, vesicular or folliculaire, trabéculo-vesicular)
   The most often, the clinical picture limits itself to a nodule of the thyroid isolated or partner to ganglia.
   To a stage more evolved, the physician feels a thyroid tumor lasts, irregular, with ganglia provoking signs of local compression (difficulties to breathe, to swallow, collateral venous circulation, paralysis of the recurrent nerve resulting in anomalies of the voice). Of the bony metastases (bony pains, spontaneous fractures) or pulmonary (cough, respiratory hindrance) can attract the attention.
   The thyroid function is normal: there is not sign of hyper nor hypothyroïdie.
   The dosages of the thyroid hormones and the TSH are normal.
   The scan eliminates the diagnosis of cyst but doesn't permit to affirm the cancer. The puncture has little interest.
   The scintigraphie to the iodine or to the technétium shows a nodule says "cold" because not fixing the isotope and appearing like a hole on the cliché.
   Only the anatomo-pathological exam permits a precise diagnosis.
   The research of metastases gets used by scintigraphie to the iodine with bodily sweep.
b) medullary Cancer
   It is also a differentiated cancer developed from the C cells of the thyroid, secreting the calcitonine. It represents less 5% of the cold nodules. This tumor dons a hereditary character.
   Clinically, the physician feels a thyroid nodule. A motor diarrhea, of the access of redness of the face (flushs) are noted sometimes. They are due to the hypersécrétion of calcitonine.
   The scintigraphie shows a cold nodule.
   The dosages of calcitonine and the carcino-embryonic antigen (ACE) are raised.
   A phéochromocytome can be associated.
c) undifferentiated Cancer
  It represents less 1% of the cold nodules.
   Clinically, the thyroid is hard, infiltrated in mass, adhesive to the other plans. The signs of local compression are present. The general state is altered.
   The scintigraphie shows a weak heterogeneous fixing. The puncture confirms the diagnosis.
 ..Thyroid cancer: Treatment
For the differentiated cancer, the treatment rests on the surgery: ablation of the thyroid (united or bilateral thyroïdectomie) associated to the substitutive thyroid treatment by thyroid hormones. A complementary treatment to the radioactive iodine is associated.
The prognosis depends on the histological type: the cancer papillaire has a better prognosis that the trabéculo-vesicular cancer. Globally, the prognosis is especially good enough before 40 years because these are cancers hormonodépendants.
For the undifferentiated cancers, radiotherapy or palliative chemotherapy.
In the families affected by multiple endocrine néoplasie, the tracking of a thyroid medullary cancer can be practiced since the birth thanks to the test of stimulation by the pentagastrine. A preventive treatment can be set in motion at the child.
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