From each exposure concentration, 20 fish were sampled for whole-body thyroid hormone analyses, and a further 10 fish in each exposure group were fixed by immersion in 10% phosphate-buffered formalin for histologic examination of thyroid follicles
, taking fish with an even distribution between the triplicate tanks.
in rats in the NC group were similar in size, development, and maturation and exhibited a lobular pattern (Figure 2).
A, Infiltrating plasma cells and intervening fibrosis replacing thyroid follicles
with a background showing Hashimoto thyroiditis.
Caption: FIGURE 4: Thyroid histopathology showing destruction of thyroid follicles
. Numerous lymphoid follicles were seen with lymphocytes infiltrating into the surrounding fibrocollagenous tissue.
Pathologically, early in the disease process, there is disruption of the thyroid follicles
with release of the colloid into the stroma.
The natural history of benign nodular goiter is largely variable and unpredictable in a given patient because no specific predictive growth parameters exist.[sup] The main pathological process of goiters is that proliferation and degeneration occur alternatively in thyroid follicles
for a long period, thereby facilitating the proliferation of fibrous tissues in the thyroid.[sup] In addition, lobules or follicles full of colloids are often surrounded by fibrous tissues and the fibro-capsule surrounding the nodule may reduce the blood supply of some follicles, resulting in necrosis, hemorrhage, cyst formation, scar formation, and calcification of follicles.
Hashimoto thyroiditis (HT) is an organ specific auto-immune disease characterized by presence of auto-antibodies against thyroid antigens, infiltration of leukocytes within the thyroid follicles
and destruction of thyrocytes, with a male/female ratio of 1:10-1:20.
Thiocyanate and isothiocyanate compete with iodite to enter into the thyroid follicles
, which may compromise the THs synthesis and induce the onset of goiter and hypothyroidism in patients with low iodine intake.
The thyroid follicular cells (TFCs), the most numerous cells of the thyroid gland that form the thyroid follicles
, are spherical structures serving as a storage site for thyroid hormones and are essential for thyroid morphogenesis (9).
The diagnostic criteria of primary TGDC are; (a) histopathological identification of TGDC itself; (b) the presence of thyroid follicles
in the cyst wall; (c) the existence of normal thyroid tissue adjacent to the tumor and (d) the absence of primary carcinoma in the thyroid7.
Lymphocytic thyroiditis also suffered as auto immune thyroiditis characterized by lymphocytic infiltration of thyroid gland with progressive destruction of thyroid follicles
. Idiopathic thyroid degeneration is characterized by loss of thyroid parenchyma with replacement with adipose or fibrous tissue.
It is thought that hyperthroidism develops as a result of rapid release of thyroid hormone into the blood due to destruction of thyroid follicles