Diseases of the Thyroid Gland - PowerPoint PPT Presentation

1 / 82
About This Presentation
Title:

Diseases of the Thyroid Gland

Description:

Diseases of the Thyroid Gland – PowerPoint PPT presentation

Number of Views:1025
Avg rating:3.0/5.0
Slides: 83
Provided by: es7
Category:
Tags: diseases | gland | merl | thyroid

less

Transcript and Presenter's Notes

Title: Diseases of the Thyroid Gland


1
(No Transcript)
2
Pathology of the Thyroid Gland
  • Edward B. Stelow, M.D.
  • May 10, 2007

3
Reading Assignment
  • Rubin and Farber, 4th ed., pp. 1134-49
  • You are responsible for all the information in
    the handout
  • Questions to es7yj_at_virginia.edu

4
You and Your Thyroid
  • Anatomy and Physiology
  • Congenital Disease
  • Hyperplasia / Goiter
  • Hypo and Hyperthyroidism
  • Graves, Thyroiditis
  • Neoplasia

5
Anatomy
  • Normal - Two lobes, connected by the isthmus,
    below the thyroid cartilage anterior to the
    trachea
  • 20 g

6
Anatomy / Development
  • The thyroid gland forms via the thyroglossal duct
    which develops at the foramen cecum (base of the
    tongue) and grows caudally
  • 4th and 5th branchial pouches also contribute
    with possibly neural-crest derived C-cells
  • Duct should involute

7
Histology
  • Follicles lined by single layer of cuboidal to
    columnar epithelium surrounding proteinaceous
    material (colloid). C-cells cannot normally be
    seen

8
Physiology
  • Triiodothyronine (T3) and tetraiodothyronine (T4)
    secreted by thyrocytes under influence of thyroid
    stimulating hormone (TSH), which is in turn under
    the influence of thyrotropin releasing hormone
    (TRH)
  • Feedback loop
  • Normal loop requires iodine

9
Physiology
  • T3 is most active form
  • Active form is unbound by thyroxine binding
    globulin
  • Stimulates basal metabolic rate (catabolism and
    anabolism)

10
Congenital Anomalies
  • Lingual Thyroid
  • Thyroglossal Duct Cyst
  • Ectopic Thyroid Tissue
  • Lateral Aberrant Thyroid
  • Congenital Hypothyroidism

11
(No Transcript)
12
(No Transcript)
13
Thyroglossal Duct Cyst
14
Congenital Hypothyroidism
  • Dysgenesis, dyshormonogenetic goiter, enzyme
    deficiencies
  • Associated with developmental abnormalities and
    mental retardation

15
Hyperplasia / Goiter
  • Non-neoplastic, non-inflammatory enlargement of
    the thyroid gland
  • Diffuse and/or nodular simple or multiple
  • Most commonly results from compensatory
    hypertrophy due to iodine deficiency (Patients
    often still euthyroid, for the most part)
  • Present due to mass
  • Female to male 8 to 1

16
Hyperplasia / Goiter
  • Gland is enlarged diffusely or with nodules
  • Follicles of variable size lined by cuboidal to
    columnar cells
  • Stromal hemorrhage and fibrosis are often present

17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
Hypothyroidism
  • Defective synthesis of thyroid hormone.
  • Inadequate function of thyroid parenchyma
  • Inadequate secretion of TSH

23
Hypothyroidism
  • Myxedema (proteoglycan accumulation). (boggy,
    hoarse, dry and cool skin, ecchymoses). Bloated
    appearance
  • Depression, lethargy, sensory defects, dulled
    tendon reflexes
  • Cardiomegaly
  • Constipation
  • Anovulation Erectile Dysfunction

24
Hyperthyroidism
  • Presence of abnormal thyroid stimulator.
  • Intrinsic thyroid disease.
  • Excess TSH production.

25
Hyperthyroidism
  • Exophthalmos
  • Tachycardia, sweating, weight loss despite
    appetite, tremor, oligomenorrhea
  • Fine Hair
  • Goiter
  • Diarrhea
  • Causes include Graves disease, toxic goiter, and
    toxic neoplasm (adenoma)

26
Graves Disease
  • Most frequent cause of hyperthyroidism
  • IgG antibodies to TSH receptor function as
    agonists
  • Thyroid becomes hyperplastic
  • Antibodies actually heterogeneous
  • Genetic factors (familial), Sex (more common in
    women), Psychology?, Smoking

27
Graves Disease
  • Pathology, Gross- symmetrically enlarged (35-50
    g), firm and red
  • Pathology, Micro- Hyperplastic with tall,
    columnar epithelium with scalloped colloid.
    Epithelial tufting or papillary formation

28
(No Transcript)
29
(No Transcript)
30
(No Transcript)
31
Thyroiditis
  • Inflammation of the thyroid gland
  • Autoimmune, infectious and other etiologies

32
Autoimmune Thyroiditis
  • Hashimoto Thryoiditis
  • Active T-helper cells (CD4) stimulate cytotoxic
    T-cells (CD8) and B-Cells (Ab against thyrocyte
    antigens thyroid microsomal peroxidase (95),
    thyroglobulin (60) and TSH receptor)

33
Autoimmune Thyroiditis
  • Lymphocytes accumulate and destroy thyroid and
    block TSH receptor
  • Results in goitrous change and can result in
    hypothyroidism (most common cause of goiter in
    children)
  • Associated with genetics (familial) and
    environment (iodine intake)
  • 10x more common in women

34
Autoimmune Thyroiditis
  • Pathology Gross- Diffusely enlarged and somewhat
    nodular thyroid (60-200 g)
  • Pathology Micro- Lymphoplasmacytic inflammatory
    infiltrate with atrophic follicles and oncocytic
    (Hurthle/Askanazy cell) metaplasia. Fibrosis can
    be present.

35
(No Transcript)
36
(No Transcript)
37
(No Transcript)
38
Acute and Subacute Thyroiditis
  • Acute- Rare, hematogenous spread of bacteria
    (Staph or Strep), treated with antibiotics.
  • Subacute (De Quervains)- possible viral
    etiology, variable, self-limited course, fever,
    thyroid dysfunction, mass. 5x more common in
    women.
  • Subacute histology- Macrophages, lymphocytes and
    giant cells surround damaged follicles.

39
(No Transcript)
40
(No Transcript)
41
(No Transcript)
42
(No Transcript)
43
Neoplasia
  • Papillary Carcinoma
  • Anaplastic Carcinoma
  • Follicular Adenoma
  • Follicular Carcinoma
  • Medullary Carcinoma
  • Lymphoma

44
Papillary Carcinoma
  • Most common thyroid malignancy (70-90)
  • Women Men 31
  • Risk factors include Iodine excess, radiation,
    genetics (RET translocation), thryoiditis,
    hyperplasia

45
Papillary Carcinoma
  • Pathology, Gross- Unifocal or multifocal, lt5mm
    (occult) to large, pale, firm and gritty
  • Pathology, Micro- Branching papillae with
    fibrovascular cores and/or follicle formation.
    Cuboidal to columnar cells with definitive
    nuclear features (enlargement, overlap, central
    clearing, pseudoinclusions, grooves). Fibrosis
    and psammoma bodies can be present.

46
Papillary Carcinoma
  • Patients present with thyroid or lymph node
    nodule
  • Will frequently metastasis to the lymph nodes
    (50)
  • Excellent prognosis even with metastases
    (patients rarely die of disease)

47
(No Transcript)
48
(No Transcript)
49
(No Transcript)
50
(No Transcript)
51
(No Transcript)
52
(No Transcript)
53
(No Transcript)
54
(No Transcript)
55
(No Transcript)
56
(No Transcript)
57
Follicular Adenoma
  • Benign neoplasm with follicular architecture
  • Presents as solitary mass
  • Most common neoplasm of the thyroid
  • Women Men 71
  • 4th to 5th decade

58
Follicular Adenoma
  • Pathology, Gross- Single, well-defined,
    surrounded by a capsule, fleshy, lt5 cm
  • Pathology, Micro- Uniform follicles (most
    commonly micro-follicles) surrounded by a fibrous
    capsule (other patterns can exist)
  • Pathology, Micro- !!Should not have vascular
    invasion or extra-capsular extension (Follicular
    Carcinoma)!!

59
(No Transcript)
60
(No Transcript)
61
(No Transcript)
62
Follicular Carcinoma
  • Uncommon, lt15 of thyroid malignancy
  • Follicular patterned carcinoma without papillary
    formations or nuclear features of papillary
    carcinoma
  • Minimally invasive (3 develop mets) or widely
    invasive (50 develop mets)
  • Minimally Invasive- focal angio-invasion or
    capsular penetration
  • Tumor spreads hematogenously (bone and lung),
    unlike papillary carcinoma

63
(No Transcript)
64
(No Transcript)
65
(No Transcript)
66
(No Transcript)
67
(No Transcript)
68
(No Transcript)
69
(No Transcript)
70
Anaplastic Carcinoma
  • 10 of thyroid cancer
  • ANAPLASTIC Sheets of bizarre cells.
  • Develop in pre-existing papillary carcinoma in
    older individuals
  • Large, invade adjacent vital structures.
  • Universally fatal (6 mo)

71
(No Transcript)
72
Medullary Carcinoma
  • 5 of thyroid carcinoma
  • Arises from C-cells
  • 80 sporadic, 20 familial (MEN 2A and B, RET
    mutation)
  • Familial (AD) presents at a younger age and is
    associated with C-cell hyperplasia
  • Secrete calcitonin (can be measured as a serum
    level).
  • 50 5 year survival
  • Can have both lymph node and hematogenous spread

73
Medullary Carcinoma
  • Pathology, Gross- Superior thyroid, can be
    multicentric (familial), circumscribed, grey
    white
  • Pathology, Micro- Variable histologic appearance
    often with amyloid. Tumor cells often have
    nested appearance.

74
(No Transcript)
75
(No Transcript)
76
(No Transcript)
77
(No Transcript)
78
(No Transcript)
79
(No Transcript)
80
(No Transcript)
81
Lymphoma
  • 2 of thyroid cancers
  • Arise in background chronic thyroiditis
  • Prognosis like that of other lymphoma unless
    tumor is low-grade and restricted to the thyroid
    (prognosis is then excellent)

82
Questions
Write a Comment
User Comments (0)
About PowerShow.com