Pathologic anatomy of the thyroid gland

Anomalies of development. Aplasia is found very rarely at an early age. Hypoplasia is more likely to occur in the fetus in the endemic areas and is caused by lack of iodine in the organism of the mother.
The anomaly of development is also evident preserving the thyroglossal duct. In most cases, the continuing duct ends blindly, leading to the formation of the midline cervical cyst. In the wall of the cyst can meet the remains of the parenchyma of the thyroid gland. Cyst lined epithelium, which is a continuation of the epithelium of the pharynx. The epithelium of cysts can be a source of tumor development.
Additional (aburrirse) the thyroid gland is divided localization in the middle (in the basis of language, above and below the hyoid bone, isthmus between cancer and the jugular notch) and side (along the jugular vein). Their existence is connected with the delay in the development of cancer in embryogenesis or extension education rudiments of the side - derivatives pharyngeal pockets. With increased development incremental thyroid parenchyma major share gland reduced in size.
Dystopia is due to the vicious bookmark body, and therefore changed the location of the cancer. There are mediastinal, vnutriportovaya, vnutrikletochnaya, retroesophageal and other localization of the thyroid gland (Fig. 5). Sometimes the extension of the thyroid gland is found in the heart bag, myocardium.

Fig. 5. Options dystopia thyroid (sagittal section, the scheme): 1 - normal localization; 2 - tireoglobulina (cyst); 3 - sublingual; 4 - lingual; 5 - interlingually; 6 - pretracheal; 7 - intraesophageal; 8 - intratracheal;9 - intratorakaalsete (chest).

Disorders of blood circulation. Arterial blood thyroid gland was observed in diphtheria, scarlet fever, influenza, tireotoksicski goitre, stress. She is accompanied by a persistent expansion of capillaries, sinusoidal with the phenomena of presteza in them.
Venous hyperemia marked with pulmonary hypertension, tumors of a thyroid gland, or of neighbouring authorities, the host strum.
Bleeding in the thyroid gland (Fig. 6) were observed when the thyroid goiter, newborn asphyxia, acute infectious diseases, tumors. The blood poured into the cavity of the follicles or stroma. After extensive hemorrhage cysts are formed and fields sclerosis.
Thrombosis and embolism vessels thyroid rare and occur mainly in tumor nodes, sometimes after strumektomii. Thrombosis of vessels leads to the development of ischemic necrosis of the tissue of the thyroid gland.

Fig. 6. Hemorrhage in the stroma of the thyroid gland in hypertensive disease (H).
Fig. 7. Atrophy of thyroid gland cancer of the larynx. Substitution stromal fibrosis (XI80).

Atrophy of the thyroid gland (Fig. 7) noted with debilitating diseases, pathologies of other endocrine glands (pituitary, adrenal), long-term use of radioactive iodine, medicines thiourea. Dimensions and weight of the thyroid gland thus diminishing. Histologically marked reduction in the size of follicles, flattening follicular epithelium, substitution fibrosis, hyalinosis or lipomatous stroma, the weakening of the PAS-reaction basal membranes of the follicles and colloid. Sharp atrophy of the thyroid gland was observed in the so-called multiple sclerosis endocrine glands and treasuremania syndrome.
Dystrophic processes. Hyalinosis stroma is noted in the outcome of the age of atrophy of the thyroid gland, as well as with Riedel peak goiter (see Goiter) and tumors.
Amyloidosis can be isolated or manifestation of the overall process. Histologically amyloid masses are identified in majolicaware stroma, the walls of blood vessels, basal membranes of follicles. Amyloidosis thyroid gland can lead to its atrophy (Fig. 8).

Fig. 8. Amyloidosis thyroid gland in General amyloidosis. Atrophy of the parenchyma. The deposition of amyloid masses along the fibers of stroma (H).

Obesity follicular epithelium is accompanied by the appearance of small droplets of fat in the cytoplasm and is observed when cretinism, prolonged venous stagnation, senile atrophy. Lipomatous stroma occurs by age gland atrophy and General disorder of fat metabolism.
Pigmentation is observed in gland atrophy (the accumulation of lipofuscin), in hemorrhages, hemochromatosis (hemosiderin deposition) and jaundice in newborns (deposition of bilirubin).
Hypertrophy of the thyroid gland occurs during puberty, during pregnancy, excessive production of thyroid-stimulating hormone by the pituitary gland, a lack of iodine in food, partial resection of cancer. When the thyroid gland increases in size; histologically noted the growth of follicles, resulting from majolicaware and intrafollicular Islands parenchyma of the thyroid gland, mitotically active zones follicles. The cells are higher, increasing their mitotic activity, increases the number of cells prismatic epithelium. Identify the elements of physiological regeneration: the increase of individual cells, the lengthening of the follicles and the formation of their poles foci of follicular epithelium owing to the proliferation of the latter. Hypertrophy of the thyroid gland may be a focal or diffuse. Focal hyperplastic growth can reach different sizes. Unlike a true tumor growths, follicular epithelium in hyperplastic growths capable of differentiation. Hypertrophy of the thyroid gland may be accompanied by improvement of its functional activity. This is evidenced by reinforced intrafollicular proliferation, vacuolization of the parietal area of colloid change its glow in fluorescent microscope, increased synthesis of nucleoproteins, activity codeprivate and mucoproteins enzymes, increased number of ascorbic acid.

Inflammation of the thyroid gland. Acute thyroiditis (see), most of purulent, often celebrated in the transition process of the adjacent organs (larynx, trachea, esophagus) or hematogenous the transmission. Histologically in the lumen of the follicles or stroma find polynuclear leukocytes. To the subacute thyroiditis include granulomatous, giant cell thyroiditis de quervain's. To chronic fibrosis goiter Riedel. However, the inflammatory nature of goiter Riedel questionable.
Of specific inflammation of the thyroid gland miliary TB (total of miliary tuberculosis), large solitary of tuberculoma, rarely tuberculous cavities. Infection occurs hematogenous or lymphogenous. There are cases of the transition process with neighboring organs, lymph nodes. Syphilitic defeat the thyroid gland in congenital or acquired syphilis. Observed or miliary gum (rare in congenital syphilis), often associated with specific vascular lesions, or interstitial thyroiditis. The latter is characterized by a specific growth of granulation tissue with subsequent fibrosis and atrophy cancer.
Parasitic defeat of the thyroid gland (Chagas disease) connected with invasion of trypanosomes. In the basis of the disease is the destruction of cells of the body as a result of development in them of parasites. Echinococcus is found in the thyroid gland rarely, usually in the form of one - or multi-cyst. For the most part the disease is diagnosed as cystic goiter and error installing only operation. The actinomycosis thyroid gland are very rare, accompanied by the formation of fistulas; histologically noted purulent inflammation with tissue necrosis.
General adaptation syndrome and thyroid gland. Clinical-morphological changes of the thyroid gland in response to stress (surgery, temperature effects, physical stress, acute infections, and others) are not specific. They are characteristic for the General adaptation syndrome (see). Histologically, there is a focal hyperplasia parenchyma with increased secretory activity: an increase in the height of cubic epithelium, the emergence of prismatic, uneven quantity of follicles, intrafollicular proliferation, desquamation of the epithelium, vacuolization and pale colouring of colloid in the follicles, colloidal stromal edema.