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Endo > SM_177b: Thyroid Histology / Pathology > Flashcards

SM_177b: Thyroid Histology / Pathology Flashcards

1
Q

Describe embryology of the thyroid

A

Thyroid embryology

  • Develops day 24 of gestation
  • Endodermal: 1st pharyngeal arch
  • Descends anterior to pharyngeal gut
  • Connected to tongue by thyroglossal duct which normally obliterates in week 7-10
  • Descent/maturation to adult shape completed in week 7 of gestation
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2
Q

Thyroid final location is ____

A

Thyroid final location is anterior to trachea below the Adams apple

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3
Q

Normal thyroid gland is ____, while thyroid nodules move with ____

A

Normal thyroid gland is not palpable, while thyroid nodules move with deglutition

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4
Q

Thyroid is composed of ____

A

Thyroid is composed of C-cells (parafollicular cells)

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5
Q

Summarize anatomy and development of the thyroid

A

Anatomy and development of the thyroid

  • Develops early in life
  • “H” shaped, located anteriorly in lower neck, closely associated with parathyroid glands
  • Functional unit is a follicle containing colloid, C cells are minor component
  • Moves with swallowing, normal sized gland is not palpable
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6
Q

Fine needle aspiration biopsy is advantageous because it is ____, ____, ____, and ____

A

Fine needle aspiration biopsy is advantageous because it is simple, safe, accurate, and expensive

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7
Q

Describe the thyroid fine needle aspiration biopsy reporting guidelines

A

Thyroid fine needle aspiration biopsy reporting guidelines

  • First line test for investigating most thyroid nodules
  • Marked female predilection for all thyroid disease
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8
Q

Thyroglossal duct cyst is ____

A

Thyroglossal duct cyst is midline spherical cystic mass closely associated with hyoid bone that moves with deglutition

  • Abnormal persistence of thyroglossal duct
  • Lined by cuboidal or squamous epithelium, contains proteinaceous fluid, ± follicles
  • Successful surgery needs removal of mid-portion of hyoid bone (Sistrunk procedure)
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9
Q

Chronic lymphocytic (Hashimoto) thyroiditis is ____

A

Chronic lymphocytic (Hashimoto) thyroiditis is autoimmune destruction of the gland caused by circulating antibodies against thyroglobulin and thyroid peroxidase

  • 45-65 years
  • Female predominance
  • Increased risk for other autoimmune diseases, B-cell non-Hodgkin lymphomas, papillary thyroid carcinoma
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10
Q

Describe pathology of chronic lymphocytic (Hashimoto) thyroiditis

A

Chronic lymphocytic (Hashimoto) thyroiditis pathology

  • Gross: diffusely enlarged gland, solitary nodule sometimes
  • Histology: excessive infiltration of parenchyma by small lymphocytes / plasma cells with germinal centers, follicles atrophic and lined by regenerating Hurthle cells
  • Cytology (fine needle aspiration): Hurthle cells and heterogeneous population of lymphoid cells
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11
Q

Hurthle cells are ____ and are seen in ____

A

Hurthle cells are a metaplastic response of normally low cuboidal epithelium to ongoing injury and are seen in chronic lymphocytic (Hashimoto) thyroiditis

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12
Q

Graves disease is the most common cause of ____ is caused by ____

A

Graves disease is the most common cause of endogenous hyperthyroidism and is caused by breakdown in self-tolerance to thyroid autoantigens (most importantly TSH receptor)

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13
Q

Graves disease presents with triad of ____, ____, and ____

A

Graves disease presents with triad of hyperplasia of thyroid gland, opthalmopathy, dermatopathy

  • Peak between 20-40 years
  • Treatment is radioactive iodine or drug therapy
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14
Q

Graves disease papillae LACK ___

A

Graves disease papillae LACK nuclear features of papillary carcinoma

  • Gross: thyroid diffusely and symmetrically enlarged
  • Papillary hyperplasia with tall follicular cells
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15
Q

Goiter is ___

A

Goiter is enlarged thyroid gland

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16
Q

Most thyroid nodules are ___

A

Most thyroid nodules are hyperplastic

17
Q

Describe stages of adenomatous (colloid or hyperplastic nodules)

A

Stages of adenomatous (colloid or hyperplastic nodules)

  • Hyperplastic: follicle lumen small, scant colloid, tall columnar epithelium, some papillae
  • Degenerative changes: fibrosis, hemorrhage, regeneration / repair, dystrophic calcification
  • Involutional stage: follicles distended with colloid, lined by small cuboidal / flat epithelium
18
Q

Benign thyroid neoplasms are usually ____, while malignant thyroid neoplasms are usually ____

A

Benign thyroid neoplasms are usually adenomas, while malignant thyroid neoplasms are usually well differentiated carcinomaas (papillary, follicular)

19
Q

Describe follicular / Hurthle cell adenoma

A

Fzollicular / Hurthle cell adenoma

  • Gross: typically discrete, solitary, nonfunctional masses derived from follicular epithelium
  • Clinically difficult to distinguish from dominant nodules in hyperplastic gland and usually impossible to predict which are follicular carcinomas until they are excised
20
Q

Follicular / Hurthle cell adenomas exhibit ____, ____, and ____

A

Follicular / Hurthle cell adenomas exhibit uniformly sized follicles, surrounding fibrous capsule, and compression of adjacent follicles

21
Q

____ is important for determining malignant potential

A

Integrity of thyroid tumor capsule is important for determining malignant potential

  • Adenomas: capsule thin, uniform, completely intact
22
Q

Describe cytology of follicular/Hurthle cell neoplasm

A

Follicular/Hurthle cell neoplasm cytology

  • Repetitive pattern of microfollicles and rosettes
  • Single cell type, scant colloid
  • Distinction between follicular adenoma and carcinoma is not possible by fine needle aspiration
  • Fine needle aspiration diagnosis: follicular neoplasm
23
Q

Malignancy in follicular neoplasm is determined by ___ and ___

A

Malignancy in follicular neoplasm is determined by capsular invasion and vascular invasion

  • Genetic changes: RAS mutations, PAX8-PPARG fusion gene
24
Q

___ is the most common thryoid malignancy

A

Papillary carcinoma is the most common thryoid malignancy

  • 20-40 years old
  • Associated with radiation
  • Nonfunctional
  • Can present initially as cervical lymph node metastasis
  • Usually great prognosis, metastasize to lymph nodes
  • Associated with activation of MAP kinase pathway
25
Q

Papillary carcinoma hallmark diagnostic feature is ___

A

Papillary carcinoma hallmark diagnostic feature is atypical nuclear morphology

26
Q

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features clinically sand genetically behaves like a ___

A

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features clinically sand genetically behaves like a follicular neoplasm

  • Used to describe follicular variant of PTC
27
Q

Poorly differentiated carcinoma lack ___ and correlate with ___ on histology

A

Poorly differentiated carcinoma lack an obvious follicular or papillary pattern and correlate with insulae (nests) on histology

28
Q

____ is a neuroendocrine neoplasm derived from C cells and accounts for 5% of thyroid neoplasms

A

Medullary carcinoma is a neuroendocrine neoplasm derived from C cells and accounts for 5% of thyroid neoplasms

  • Most sporadically, remainder as MEN 2A or 2B or familial tumors
  • Activating point mutations in RET proto-oncogene involved in development of familial and sporadic
  • Serum calcitonin and CEA important markers for diagnosis / recurrence monitoring
29
Q

Medullary carcinomas are ___ and typically arise from ___

A

Medullary carcinomas are non-encapsulated and typically arise from junction of middle and upper thirds of thyroid lobes (C-cells most densely dispersed)

  • Histology: variable, acellular amyloid deposits, calcitonin positive, familial has multicentric C-cell hyperplasia
30
Q

Anaplastic (undifferentiated) carcinomas of thyroid present with ___

A

Anaplastic (undifferentiated) carcinomas of thyroid present with extensive loca; extensive beyond the thyroid

  • High-grade carcinomas with no obious follicular differentiation, extreme cellular / nuclear pleomorphism, necrosis
31
Q

Metastatic thyroid tumors are ___

A

Metastatic thyroid tumors are rare

32
Q

Thyroid lymphoma is often associated with ____ and predominantly ____

A

Thyroid lymphoma is often associated with Hashimoto’s thyroiditis and predominantly non-Hodgkins lymphoma B cell type

  • Low grade (MALT): difficult to distinguish from chronic lymphocytic (Hashimoto) thyroiditis
  • High grade: mimics anaplastic carcinoma
33
Q

Parathyroid cyst / adenoma is ____

A

Parathyroid cyst / adenoma is enlarged intrathyroidal parathyroid that can be occassionally encountered as a nodule

  • Difficult to distinguish from follicular cells
34
Q

Thyroid enlargement nodules are ____ common in women than men

A

Thyroid enlargement nodules are more common in women than men

35
Q

___ is most useful screening and diagnostic test for thyroid nodules

A

Fine needle aspiration is most useful screening and diagnostic test for thyroid nodules

36
Q

Common thyroid neoplasms have ____ prognosis

A

Common thyroid neoplasms have good prognosis

Endo (25 decks)

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