Focal thyroiditis

Thyroiditis, autoimmune. Inflammatory destruction of the thyroid gland (ranging from a mild focal thyroiditis to extensive... 

Focal thyroiditis is more common than diffuse or Hashimotos thyroiditis before and after iodine prophylaxis. 

All OCPs are polytropic, parenchymatous poisons, afflicting the central nervous system, liver, kidneys, the heart muscle, the stomach and intestines, and the endocrine system (mostly the adrenal glands, thyroid, and ovaries). Morphological changes in warm-blooded creatures poisoned by OCPs vary from insignificant disruptions in circulation and reversible dystrophy to focal necroses these effects depend on the organism, the dose of OCP, how long the OCP remains active, as well as on other factors [9, 39, 40, A47, A79]. 

An increase in plethora and focal dystrophic changes in the endocrine system matches clinical observations of changes in adrenal and thyroid function, as well as changes in local and general vascular dystonia, all detected in humans poisoned by OCP. Morphological changes in the brain s nerve cells conform to information on the disruption of reflex activity in the early stages of OCP exposure. 

Poorly differentiated thyroid carcinomas of the insular type are usually TGB positive, although the extent of cellular staining is generally weak and focal.Undifferentiated (anaplastic) thyroid carcinomas are most commonly negative for TGB. In the series reported by... 

In their study of thyroid and pulmonary carcinomas, Kaufmann and DieteP" demonstrated reactivity for surfactant protein A in 3 of 7 thyroid carcinomas in a focal pattern. Byrd-Gloster and coworkers reported that TTF-1 is useful in the distinction of pulmonary small cell carcinomas from Merkel cell carcinomas. In their study, 97% of small cell bronchogenic carcinomas were TTF-1 positive, whereas none of 21 Merkel cell tumors exhibited positivity. However, TTF-1 has been reported in some nonpulmonary small cell carcinomas including those arising in the prostate, urinary bladder, and uterine cervix (see Table 10.6). ... 

The overwhelming majority of neuroendocrine neoplasms occurring in the liver are metastatic. Well to moderately differentiated neuroendocrine neoplasms (e.g., carcinoids, pancreatic endocrine neoplasms, medullary thyroid carcinomas) may mimic primary hepatocellular processes, and thus immunohistochemistry with antibodies for chromogranin, synaptophysin, and CD56 can be extremely helpful, as discussed earlier. They may also be positive for MOC-31 but not for Hep Par-1. In contrast, HCC may occasionally show focal neuroendocrine differentiation and may stain for synaptophysin. 

Histological autoimmune thyroiditis related to iodine intake are generally referred to in the literature as focal or Hashimotos in type, regardless of their clinical features as these are almost always an incidental finding in thyroidectomies or at autopsy. In this review, we will focus... 

The concept of a relationship between dietary iodine intake and autoimmune thyroiditis, either focal or Hashimoto s, suggests that its prevalence generally increases after iodine prophylaxis (Table 89.3). The prevalence of thyroiditis in both sexes shows a wide range in iodine-deficient areas before (0%—20.6%, mean 7.6%) and after (6.5%—29.7%, mean 16.6%) iodine prophylaxis, whereas in areas of iodine sufficiency the rate for female patients ranges from 7.7 to 45.5% (mean 21.8%) (Table 89.4). However, a comparison between these studies is difficult because methods have changed over time and similar selection criteria were not used by all the authors. 

Autoimmune thyroiditis may show focal or diffuse lymphoid infiltrates on histology. 

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