Practice question answers II Pathology of thyroid
Practice question answers II
Pathology of thyroid
© Jun Wang, MD, PhD
1. A. An evenly enlarge thyroid gland without abnormal thyroid function
is most consistent with simple
goiter, most commonly caused by iodine deficiency. Follicular
adenoma and papillary
thyroid carcinoma have discrete growth. Graves
disease has presentations of thyrotoxicosis.
Hashimoto
thyroiditis is characterized by thyroitoxicosis
at early phase and hypothyroidism
at later phase.
2. C. Endemic goiter
is most commonly caused by iodine deficiency. Autoimmune process is associated with
Graves
disease and Hashimoto
thyroiditis. Bacterial infection is seen in acute thyroiditis. Ret mutation is seen in medullary
carcinoma and papillary
thyroid carcinoma. Viral infection may be associated with granulomatous
thyroiditis (de Quervain's thyroiditis).
3. B. Cycling changes of follicular hypertrophy due to TSH effects and involution
is thought to cause thyroid enlargement in patients with goiter.
Activating antibodies against TSH receptor is seen in Graves
disease. Proliferation of parafollicular cells are seen in C cell
hyperplasia and medullary
carcinoma. Autoantibodies against thyroid peroxidase or thyroglobulin are
seen in Hashimoto
thyroiditis. In addition, follicular destruction is NOT a feature of
goiter.
4. C. Unevenly benign enlargement of thyroid with nodular pattern is multinodular
goiter. Follicular
adenoma has packed small follicles, usually similar sizes. Graves
disease has presentations of thyrotoxicosis.
Squamous cell carcinoma has typical features of squamous differentiation, such
as intercellular bridges and/or squamous pearls. Thyroglossal
duct cyst may contain ectopic thyroid tissue, but is typically a cyst lined
by with stratified squamous or respiratory type epithelium.
5. E. Thyrotoxicosis
in a background of multinodular
goiter is most likely toxic goiter (Plummer syndrome). Granulomatous
thyroiditis is may have transient thyrotoxicosis,
and it has follicular destruction and granulomatous changes, such as
multinucleated giant cells, in the absence of microorganism. Follicular cell
activation as characterized by columnar shape with finger like crowded growth,
as well as thin pale colloid are seen in Graves
disease, but these changes are diffuse, not focal, in Graves
disease. Hashimoto
thyroiditis is characterized by follicular destruction in a
background of diffuse polyclonal lymphoid infiltrate, with or without lymphoid
follicle formation. Follicular
carcinoma has packed small follicles with vascular or capsular invasion.
6. A. Well-formed nodular growth of packed small follicles with normal
appearing follicular cells is follicular
adenoma, if no invasion can be seen. Follicular
adenoma can be functional with presentations of thyrotoxicosis.
Follicular
carcinoma has packed small follicles with vascular or capsular invasion. Graves
disease is characterized by proliferation of follicular cells, thin
pale colloid with vacuoles adjacent to follicular cells, with intact follicular
structure. Hashimoto
thyroiditis is characterized by follicular destruction in a
background of diffuse polyclonal lymphoid infiltrate, with or without lymphoid
follicle formation. Papillary
thyroid carcinoma, including follicular variant, is diagnosed based
on typical nuclear features, such as enlarged nuclei, washed out chromatin,
nuclear grooves or inclusion.
7. D. Activating mutation of TSH receptors is seen in many cases of
toxic follicular
adenoma. Activating antibodies against TSH receptor is seen in Graves
disease. Destruction of follicles may cause elevated thyroid
hormone, as in Hashimoto
thyroiditis and granulomatous
thyroiditis. Negative feed back to pituitary TSH producing cells
will lead to higher, NOT lower, levels of TSH.
8. A. See discussion in question 6.
9. E. See discussion in question 6.
10. D. Papillary
thyroid carcinoma is most commonly associated with RET-PTC translocation.
Menin 1 mutation is seen in MEN 1, characterized by tumors of parathyroid
glands, the enteropancreatic endocrine cells, the anterior pituitary gland, and
the skin. PAX8 and PTEN mutation is seen in various tumors, including follicular
carcinoma of thyroid. TSH receptor mutation may be seen in toxic follicular
adenoma.
11. C. One of the most characterized feature for papillary
thyroid carcinoma is its tendency to be multifocal and bilateral. Regression
with iodine supplementation may be seen in patient with iodine deficiency
associated goiter.
12. E. Clear
cell type renal cell carcinoma is characterized by islands of cells with
clear cytoplasma and fine vasculature, not nuclear inclusion or grooves. Also
see discussion in question 6.
13. D. See discussion in question 10.
14. E. Total thyroidectomy is the appropriate management for papillary
thyroid carcinoma.
15. C. Follicular
carcinoma has packed small follicles with vascular or capsular invasion. Anaplastic
thyroid carcinoma is an undifferentiated malignant tumor with markedly atypical
tumor cells. Also see discussion of question 6.
16. C. p53
mutation is usually seen high grade malignancies, including Anaplastic
thyroid carcinoma.It is usually not seen in follicular
carcinoma of thyroid. Also see discussion is question 10.
17. D. A thyroid
tumor with eccentric nuclei, punctuate chromatin, and amyloid deposit, but has with
no follicular differentiation is likely to be medullary
thyroid carcinoma. Anaplastic
thyroid carcinoma is an undifferentiated malignant tumor with markedly atypical
tumor cells. Also see discussion of question 6.
18. D. Activating
RET mutation can be seen in medullary
thyroid carcinoma. Also see discussion is question 10.
19. D. Medullary
thyroid carcinoma derived for C cells and produces calcitonin. Autoantibodies
against thyroid peroxidase or thyroglobulin, and inhibitory antibodies against
TSH receptor are seen in Hashimoto
thyroiditis. Hypercalcemia and elevated parathyroid hormone are seen
in hyperparathyroidism.
20. A. Anaplastic
thyroid carcinoma is an undifferentiated malignant tumor with markedly atypical
tumor cells. Follicular
carcinoma has packed small follicles with vascular or capsular invasion. Hodgkin
lymphoma has Reed-Sternberg or LP cells in a background of lymphocytes, and
is negative for cytokeratin. Medullary
thyroid carcinoma has eccentric nuclei, punctuate chromatin, and amyloid
deposit, and usually does not have marked pleomorphism. Undifferentiated
pleomorphic sarcoma is a diagnosis of exclusion, and is negative for
cytokeratin.
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