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Path 10
Thyroid Pathology
Question | Answer |
---|---|
Release of T3 and T4 from the thyroid is controlled mostly by ? | TSH |
What controls TSH | TRH from the hypothalamus |
The Thyroid hormone negative feedback loop is dependent upon ? | IODINE |
most thyroid hormone is bound by? | throxine binding globulin |
Is thyroid hormone active or inactive when bound to thyroxine binding globulin | not active |
C-cells release? | calcitonin (helps regulate serum calcium levels) |
Most congenital thyroid abnormalities develop secondary to ? | migration problems during embryogenesis |
what are some common congenital thryoid abnormalities | lingual thyroid, thyroglossal duct cysts, ectopic thyroid, lateral aberrant thyroid, congenital hypothyroidism |
what is linual thyroid | when the thyroid tissue is left at the base of the tongue instead of migrating |
what is a thyroglossal duct cyst | when the glandular tissue is left between the tongue and the thyroid gland and becomes cystic |
where do you see congenital hypothyroidism more frequently | in parts of the world where iodine deficiency is common |
what is a goiter | a neck mass but is often used as a term for patients with noticeable thyroid enlargement secondary to hyperplasia |
what does thyroid hyperplasia look like histologically | enlarged follicles that vary greatly in size with abundant intermixed fibrosis calcification, and hemorrhage |
what are symptoms of hyperthyroid | hypermetabolic state and symptoms such as tachycardia, sweating, weight loss, tremor, oligomenorrhea, fine hair, diarrhea, and exophtalmos |
What is the most common cause of hyperthyroidism | Graves disease (due to IgG antibodies that function as agonists to the TSH receptor |
what are some risk factors for Graves Disease | Women are more commonly affected, may have familial disposition, and smoking may be considered a risk factor |
what are characteristics of hypothyroidism | myxedema, boggy skin, bloated appearance, dry cool skin and hoarse deepened voice, depression, lethargy, sensory defects, dulled tendon reflexes, cardiomegaly, constipation, anovulation and erectile dysfunction |
what is thyroiditis | inflammation of the thyroid gland (autoimmunity or infection usually) |
what is the most common type of thyroiditis | hashimoto (autoimmune) |
how does Hashimoto thyroiditis appear grossly | diffusely enlarged somewhat nodular thyroid gland which can weigh up to 200 grams |
what do you note histologically with thyroiditis | lymphoplasmacytic infiltrate with atrophic follicles, fibrosis, and oxiphilic metaplasia |
What are two common causes of acute thyroiditis | hematogenous spread of an organism or direct trauma to the gland |
What is De Quervain's thyroiditis | self limited thyroiditis characterized clinically by fever, thyroid dysfunction, and rarely a mass |
What does De Quervain's thyroiditis look like histologically | lymphocytes, mutinucleated giant cells and histiocytes (granulomas) surrounding damaged follicles |
What is the most common malignancy of the thyroid gland | Papillary Carcinoma (70-90%) |
What are risk factors for papillary carcinoma | previous irratiation, thyroiditis, hyperplasia, iodine excess and genetic mutation |
How does Thyroid Papillary Carcinoma appear grossly | white firm gritty mass |
How does Papillary Carcinoma appear histiologically | numerous branching papillae with fibrovascular cores and follicle formation with fibrosis and psammoma bodies |
Papillary carcinoma is defined by ? | nuclear features (orphan Annie Eyes), nuclear pseudoinclusions adn grooves |
what is the most common type of neoplasm of the thyroid gland | follicular adenomas |
what is the gross appearance of follicular adenoma | single well defined lesion surrounded by a capsule. The lesion has a fleshy appearance and are usually less than 5 cm in size |
do follicular carcinomas or papillary carcinomas show hematogenous spread | follicular carcinoma |
Do follicular carcinomas metastasize? | yes up to 50% will metastasize |
Anaplastic thyroid carcinoma is thought to develop from? | pre-existing papillary or follicular carcinoma |
What is the prognosis of anaplastic carcinoma of the thyroid | Universally fatal (most patients die within 6 months of their diagnosis) |
Medullary carcinoma may be associated with MEN syndromes 2A and 2B because of germline mutations of ? | RET gene |
Medullary Carcinomas secrete what hormone | Calcitonin |
what is the five year survival of medullary carcinoma | 50% |