Pathophysiology of Thyroid Carcinoma

Thyroid Carcinoma usually capture radioactive iodine than normal thyroid gland located around the perimeter. Therefore, when done scintiscan, nodules will appear as an area with less decision, a cold lesion. Other diagnostic techniques that can be used for differential diagnosis of thyroid nodules are thyroid echography. This technique allows to distinguish carefully between the mass of solid and cystic masses. Thyroid carcinoma is usually solid, while the cystic mass is usually a benign cyst.

Thyroid carcinoma should be suspected based on clinical signs if there is only one palpable nodules, hard, basically can not be moved, and is associated with satellite lymphadenopathy.

In general it was agreed that clinical thyroid cancer can be divided into a large group of well differentiated neoplasm with a slow growth rate and high probability of healing, and a small group of anaplastic tumor with possible fatal. There are four types of thyroid cancer according to morphologic and biological: papillary, folikularis, medularis, and anaplastic. (Price, 1995, p: 1078)

Papillary carcinoma of the thyroid gland is usually a hard nodule, single, "cold" on the isotope scan, and "solid" on thyroid ultrasonography, which is very different from other parts of the gland. At multinodular goiter, cancer is a "dominant nodule" bigger, louder and clearer than the surrounding parts. Approximately 10% of papillary carcinomas, especially in children, with enlarged cervical lymph nodes, but careful inspection will usually reveal nodule "cold" on the thyroid. Rarely, will hemorrhage, necrosis and cyst formation in malignant nodules but on thyroid ultrasonography, there will be clearly bounded internal echo is useful for semi malignant cystic lesions of "pure cyst" is not malignant. Finally, papillary carcinoma can be found accidentally as a fakus microscopic cancer in the middle of the gland removed for other reasons such as: Graves' disease or multinodular goiter.

Microscopically, the tumor consists of a single layer of thyroid cells organized in "vascular stalk", by highlighting papil into microscopic spaces such as cysts. Nucleus of the cell and often pale nucleus containing inclusion bodies intra clear as glass san. Approximately 40% of papillary carcinoma forming a layered spheres classification, often at the end of both the optic disc bulge called "psammoma body", is usually diagnostic for papillary carcinoma. This cancer is usually spread by metastasis in the glands and the thyroid gland invasion and local lymph nodes. In elderly patients, they can be more aggressive and invade locally into the muscle and trachea. In stage further, they can spread to the lungs. Death is usually due to local disease, with invasion into the neck, more rarely death could disebabka extensive pulmonary metastases. In some elderly patients, a papillary carcinoma that grows slowly will begin to grow rapidly and turn into anaplastic carcinoma. Further anaplastic changes are the cause of death other than papillary carcinoma, papillary carcinoma secreting many thyroglobulin, which can be used as a sign of recurrence or metastasis of cancer.

Follicular carcinoma is characterized by the persistence of small follicles, although the formation of colloidal bad. Indeed, follicular carcinoma can not be distinguished from follicular adenomas except with capsule invasion or vascular invasion. The tumor is slightly more aggressive than papillary carcinoma and spreads either by local invasion or lymph node invasion of blood vessels accompanied by distant metastases to bone or lung. Microscopically, these cells are cuboidal shaped with large nuclei were irregular around the follicle, often containing colloid. These tumors are often still have the ability to concentrate radioactive iodine to form tiroglubulin and rarely, to synthesize T3 and T4. Thus, the function of thyroid cancer that is almost always a rare follicular carcinoma. This characteristic makes these tumors more it is likely to give good results against radioactive iodine treatment. In patients who were not treated, death due to local extension or distant metastases as the flow of blood to the extensive involvement of the bones, lungs, and viscera.

A variant of follicular carcinoma is carcinoma "Hurthle cell" which is characterized by cells individually with a huge pink cytoplasm contains mitochondria. They behave more like papillary carcinoma are rare unless they radioiodin uptake. Mixed papillary and follicular carcinoma is more like papillary carcinoma. Thyroglobulin secretion produced by follicular carcinoma can be used to follow the course of the disease.

Medullary carcinoma is a disease of the cell C (parafolikular cells) derived from primary branchial body and capable of secreting calcitonin, histaminase, prostaglandins, serotonir, and other peptides. In mikoroskopis, tumor composed of layers of cells separated by a substance that stained with red. Amyloid consists of a chain of calcitonin fibrils that are arranged in a pattern or contrast with other forms of amyloid, which can have a light chain immunoglobulins or other proteins that are deposited with a pattern Fibri.

Medullary carcinoma is more aggressive than papillary or follicular carcinomas but not as aggressive as undifferentiated thyroid cancer. This extends locally to the lymph nodes and into the surrounding muscle and trachea. Can lymphatic and vascular invasion and metastasisi to the lungs, and calcitonin viscera, and carsinoembryonic antigen (CEA) is secreted by the tumor is of clinical signs that help the diagnosis and follow-up. Approximately one-third are familial medullary carcinoma, involving multiple nodes (Multiple endocrine neoplasia type II = MEN II, Sipple syndrome). MEN II is characterized by medullary carcinoma, pheochromocytoma, and multiple neuromas on the tongue, lips, and intestines. Approximately one-third of cases of malignancy dalah alone. If medullary carcinoma at diagnosis with fine-needle aspiration biopsy or during surgery, it is important for patients examined other endocrine disorders encountered in MEN II and members examined for the presence of medullary carcinoma and MEN II. Measurement of serum calcitonin after pentagastrin stimulation or infusion of calcium can be used to screen for medullary carcinoma. Pentagastrin administered intravenously in the form of bolus 0.5 mg / kg, and venous blood samples were taken at minutes 1, 3, 5, and 10. Abnormal increase in serum calcitonin in minutes to 3 or 5 is indicative of malignancy. MEN IIA gene has been localized to chromosome 10, and it is now possible to use checks and polymorphic DNA fragment length polymorphism is limited to the identification of this syndrome gene career. So the family members who carry this gene can be identified and examined as a high risk for the onset of this syndrome.

Anaplastic carcinoma, undifferentiated thyroid gland tumors including small cell carcinoma, giant cells, and spindle cells. It usually occurs in elderly patients with a long history of goiter in which the nodes of a sudden within a few weeks or months started to grow and produce pressure symptoms, dysphagia or vocal cord paralysis, death due to local expansion which usually occurs within 6-36 months . These tumors are highly resistant to treatment.