Thyroid gland

1
Thyroid gland
2
Anatomy
3

• Bi-lobed gland over second and third tracheal
  ring
• piramidal lobe 40 50
• Weight 20 30 gr
• Epithelium lined follicle
• Colloid glycoprotein ( thyroglobulin )
• Vascular stroma
• True connective tissue capsule

4
It is important to ligate the superior thyroid
artery close to the gland to avoid injury to the
nerve during thyroidectomy
5
Inferior thyroid artery

• Inferior thyroid artery
• Thyrocervical trunk
• Absent in up to 6
• Thyroidea ima
• directly from aorta , innominate artery or
  right common carotid artery
• Present in up to 12

6

• Superior thyroid vein IJV or common facial vein
• Inferior jugular vein innominate vein or IJV
• Middle thyroid vein IJV
• Lymphatic ? paratracheal nodes ? superior
  mediastinum middle deep cervical node and
  lateral the neck

7
Embryology

• Median endodermal derivative that migrates from
  the tongue base to its normal position in the
  neck by 7th week .
• The distal portion of this thyroglossal duct
  forms the thyroid gland

8
Physiology

• Concentrate iodine
• 20 30 is store in thyroid
• Small percentage in hormone and nonthyroid tissue
  
• All tyrosine compounds are bound to thyroglubulin
  and store in thyroid follicles as colloid
• The unbound thyroid hormone is responsible for
  influencing metabolism .

9
Thyroglossal duct anomaly

• 7 of the population has remnants of the
  thyroglossal duct
• Cyst anywhere along the length of duct
• 60 infrahyoid , 24 suprahyoid ,
• 1 intralingual
• 1-2 cm cystic mass that is mobile on swallowing
  protruding of the tongue

10

• 60 contain thyroid tissue
• Malignancy is rare
• Acute infection
• Contain mucus like clear fluid
• If it is become symptomatic it must be removed
• Sistrunk operation

11
Lingual thyroid

• Failure of thyroglossal duct to descend
• A mass at the foramen cecum
• Aysmptomatic or present with airway obstruction
• May be the only thyroid tissue

12
Ectopic thyroid tissue

• Anywhere along the migratory route of the thyroid
  
• Mediastinum , larynx , trachea , pericardium or
  esophagus

13
Congenital intrathyroid cysts

• Present in children persistent ultimobranchial
  bodies or an intrathyroidal thyroglossal duct
  cyst

14
Infectious and inflammatory disorder
15
Acute suppurative thyroiditis

• MF
• Preceded by an upper respiratory tract infection
• Staph. The most common organism
• Painful enlargement of the gland
• Fever
• Abscess formation

16
Painless thyroiditis
17
Sporadic form

• More common in female
• Difuse thyroid enlarement
• Without pain or thyroid enlargement
• Temporary hyperthyroidism
• 50 become hypothyroid which resolves in 6 month
  

18
Postpartum thyroiditis

• Initial hypothyroidism is mild
• Lymphocytic infiltration and follicle disruption
• Self-limiting disease
• Steroid may be of value

19
Subacute thyroiditis ( De Quervainthyroiditis )

• At all age most common at 5th decade
• FgtM
• May be viral
• Painful thyroiditis
• Defuse thyroid enlargement
• Malaise and fever
• thyrotoxic

20
Endocrine phases

• Hyperthyroidism 1-3 month
• Euthyroid 1-3 weeks
• Hypothyroid 2-6 month
• Recovery which is complete

21

• Lymphocyte , monoycyte and giant cell
  infiltration .
• Treatment consist of analgesic steroid and
  antiinflammatory agents .

22
Hashimotos thyroiditis

• Common
• Affecting 2 population
• 95 in female Autoimmune etiology with strong
  genetic predisposition
• Diffusely enlarge with nodularity firm
• Disrupted follicle with lymphocyte and plasma
  cell infiltration and variable fibrosis
• Residual hypothyroidism

23
A thyroid scan demonstrated a salt and pepper
pattern
24

• Anti thyroglobulin and antimicrosomsal ab are
  present up to 90
• FNA is diagnostic
• Increased risk for developing B cell lymphoma

25
Riedels thyroiditis

• Uncommon
• FgtM
• Older patient
• May be mediastinal retroperitoneal fibrosis
• Fixed rock-hard thyroid enlargement
• Gland replaced with fibrosisAirway obstruction
  and dysphagia
• Palliative surgery to relieve obstruction

26
Hyperthyroidism
27
Graves Disease

• 3th and 4th decade
• F/M 7/1
• Autoimmune etiology abnormal Ig that fix on TSH
  receptor of thyroid epithelial cell
• Diffuse toxic goiter
• ophthalmopathy 55
• Dermophathy 5

28
Cont.

• ? T3 , T4 , T3RU
• Thionamide , sympathetic blocker , iodine
• Radioactive iodine

29
Pregnant women should not be treated with this
modility
30
Surgical indication

• Refuse radioactive therapy
• Thyroid nodules suspicious for malignancy
• Must be rendered euthyroid prior to surgery

31
Subtotal thyroidectomy leaving 7-8 gr of nodule
free tissue is recommended however , total
thyroidectomy is proposed by many
32
Toxic multinodular goiter

• Older patient no ophthalmopathy or dermophathy
• Total thyroidectomy
• Radioactive iodine but not successfully as surgery

33
Toxic adenoma

• Younger patient Quite large ( 2.5 3 cm )
• Surgical excision

34
Multinodular nontoxic goiter

• Compensatory response
• Common in female Secondary to dietry deficiency
• Symptom and sign of pressure

35
A small percentage (1-2) may harbor a malignancy
36
Treatment

• Thyroid suppression
• Surgery
• cosmetic deformity
• pressure symptom refractory to suppression
• Fear of malignancy
• Development of toxicity

37
Neoplasm Cyst
38
Benign adenoma

• Encapsulated tumor
• Glandular epithelium with intratumoral
  degenerative changes ( hemorrhage , fibrosis ,
  calcification )
• Rare thyrotoxicosis
• Type follicular,colloid , embryonal, fetal ,
  Hurthle ???

39
Malignant
40
Papillary carcinoma60 65

• Third 5th decade
• F/M 2/1
• Indolent with overall excellent prognosis
• May arise from benign adenoma
• Low-dose and high dose external RT

41
Macroscopic pattern

• Occult lt1.5 cm
• Intrathyroid ( 70 )
• Extrathyroid infiltrate larynx , trachea ,
  strap muscle , great vessel

42
Microscopic pattern

• Purely papillary
• Some may have area of follicular
• Anaplastic transformation is rar
• Venous invasion in 10

43
Intraglandular lymphatic invasion results in high
incidence of multicentricity
44
Neither multicentricity nor regional LN
metastasis have any prognostic significance
45
Negative prognostic indicator

• Advance age
• Male gender
• extrathyroid extension
• Distant metastasis

46
Cont.

• Dedifferentiation
• Vascular invasion
• Atypical variants ( tall cell, columnar ,
  sclerosing ) may have negative prognostic
  significance

47
Follicular carcinoma15

• Vascular invasion
• Metastasis to bone brain and liver
• Anaplastic transformation is more common
• Overtly invasive infiltrate surrounding
  structure ( MR 20-50)
• Minimally invasive microscopically has capsular
  invasion (MR 5)

48
Definitive diagnosis can often be established
only on permanent section
49
Poor prognostic indicator

• Advanced age
• Male gender extrathyroid extension
• Distant metastasis
• Vascular invasion
• anaplastic transformation trabecular growth
  pattern

50
Hurthle cell carcinoma 5

• As a variant of follicular tumors
• Overtly invasive higher mortality rate
• Higher LN
  metastasis
• Minimally invasive

51
Not all nodule containing Hurthle cell are
neoplastic .The vast majority are Hurtule cell
changes in benign follicular adenomatous nodules
or thyroiditis
52
Medullary carcinoma 3-5

• 10 20 familial
• Sporadic in 5th decade
• Multicentric ,lateral upper 2/3 of gland
• Encapsulated , diffuse infiltrative
• 50 nodal metastasis
• 15-25 distant metastasis

53
MEN type 2A

• Medullary thyroid cancer
• C-cell hyperplasia
• Adrenal pheochromocytoma
• Adrenal medullary hyperplasia
• Parathyroid hyperplasia

54
MEN type 2B

• In addition
• Mucosal neuromas
• GI ganglioneuroma
• Musculoskeletal abnormality

55
Poor prognostic indicator

• MEN type 2B
• Nodal distant metastasis
• Extrathyroid extension
• Small cell tumor pleomorphism
• Poor calcitonin staining
• High CEA

56
Anaplastic carcinoma 1-5

• Rare tumor
• Arise in well-differentiated tumor
• Older women
• Advance stage early infiltration of surrounding
  structure
• Small cell , giant cell
• Extremely poor prognosis

57
Lymphoma 1-3.5

• Primarily in the thyroid
• As a part of systemic disease
• Arises in a gland with Hashimotos thyroiditis
• Elderly women
• Diffusely enlarged gland or nodule
• Hypothyroidism
• Diffuse large cell lymphoma
• Good prognosis

58
Miscellaneous

• Sarcoma
• Mucoepidermoid carcinoma
• SCC
• Kidney , colon , melanoma are the most common
  distant site

59
Clinical presentation
60
Thyroid enlargement

• Smooth and diffuse ( usually benign )
• Nodular
• Multinodular goiter may harbor a neoplasm( 10-15
  )
• 90 benign
• 10
  malignent

61
Overall incidence of malignancy in a multinodular
goiter is only 1-2
62
Symptom sign of pressure

• Dysphagia ( discomfort on swallowing ?
  obstruction )
• Mild to moderate stridor ? chondromalacia ?
  airway obstruction
• TVC edema RLN paralysis ? hoarseness
• Retrosternal extension ? tracheal deviation SVC

63
Symptom sign of infiltration

• Stridor and hemoptysis
• Rapid increasing in mass
• RLN paralysis
• Dysphagia odynophagia
• Brachial plexus infiltration
• Painful enlargement

64
Evidence of regional and distant metastasis

• It is the only obvious clinical evidence of
  thyroid cancer
• Papillary metastasis may be cystic ( 20)
• Follicular carcinoma distant metastasis
• Medullary and anaplastic extracapsular extension

65
Evidence of endocrine dysfunction

• Most patients are euthyroid
• Occasionally hypothyroid
• Rarely hyperthyroid
• Medullary ? calcitonin , ACTH , PG secretion

66
Evaluation of a thyroid mass
67
Neck X-ray

• Patchy calcification
• Benign thyroid disease
• Well differentiated
  carcinoma
• Medullary carcinoma

68
Chest X-Ray

• Retrosternal extension
• Tracheal deviation
• Mediastinal nodal involvement
• Pulmonary metastasis

69
CXR should always be done
70
Esophagogram

• It should be done if the patient complains of
  significant dysphagia
• It differentiate thyroid from nonthyroid causes
  of dysphagia

71
Radionuclide scan

• Determine the functional status of gland
• Differentiate diffusely enlarge from nodular
• Differentiate single nodule from multinodular
  goiter

72
Tc-99

• Low cost
• Ready available
• Short half life
• Optimal imaging
• Only trapped , not organified

73
Radioactive Iodine

• It is able to determine function
• ¹²³I is the best but is expensive and have very
  short half life

74
Thallium 201

• Detecting
• lymph node metastasis
• retrosrernal extension
• recurrent disease functioning
  nodule within
  suppressed gland

75
Octreotide scintigraphy is useful for detecting
metastatic medullary and Hurthle cell carcinoma
76
Radionuclide scan no longer used as a first line
imaging study
77
Ultrasonography
78
High resolution real time US enable the
radiologist to detect nodule as small as 3mm
79
US usage

• Screening high risk patient ( prior RT )
• Differentiating single nodule from multiple
• Cystic or solid status
• Facilitating FNA
• Monitoring medically treated patient
• Evaluating clinically negative neck for
  metastasis
• Recurrent disease after surgery

80
CT scaning MRI

• Extrathyroidal extension
• Retrosternal involvement
• Metastatic disease
• Unnecessary in the evaluation of a routine
  thyroid mass

81
Metastatic workup

• Bone scan
• CT scan of abdomen and chest
• Octreotide study

82
Blood test

• T3
• T4
• TSH
• Thyroid Ab for Hashimoto thyroiditis
• Serum thyroglobulin
• Serum calcitonin in medullary carcinoma
  especially if there is a family history

83
These level may increases after FNA and should be
performed prior to it
84
Postoperative serum thyroglobulin levels under 10
ng/ml in patients under supression therapy are
indicative of cancer control
85
FNA biopsy

• Obtain satisfactory specimen from nodule
• it is of no value in microinvasive follicular
• If the report is suspicious the patient should
  probably proceed to surgery
• Inadequate specimen repeat FNA

86
FNA biopsy

• The best results obtains from periphery
• Multiple aspirates are frequently necessary

87
A negative FNA should never preclude surgical
exploration in a patient with highly suspicious
lesion
88
Large bore needle aspiration

• A portion of capsule and surrounding tissue can
  be included
• It is rarely indicated

89
Surgical exploration indication
90
Obvious malignancy

• Clinical or radiographic evidence of infiltration
• Clinical or radiographic evidence of regional or
  distant metastasis
• FNA positive for malignancy ( papillary ,
  medullary , anaplastic )
• Thyroid mass with raised serum level of calcitonin

91
Suspicion of malignancy

• Suspicious fine needle aspiration
• Nodule refractory to suppression
• Solitary thyroid nodule with raised serum
  thyroglobulin level
• Recurrent cyst refractory to two aspirations and
  thyroid suppression
• Nodule going wrong , a solitary nodule increasing
  in size and associated with pain
• True single nodule in males elderly women
  children , or in any patient with a history of
  prior RT

92
Management of thyroid Tumor
93
Every patient undergoing a thyroid exploration
should sign a very specific detail and inform
that should include the possibility of performing
throidectomy
94
Total thyroidectomy

• Better oncologic operation in the case of
  multicentric disease
• Difficult residual thyroid suppression and
  anaplastic transformation risk
• Good postoperative scanning and radioactive
  ablation
• Postoperative thyroglobulin titrage

95
Subtotal thyroidectomy

• Simpler time consuming
• Lower morbidity
• Not affected the prognosis of well differentiated
  tumor

96
Extrathyroid extension

• Well-differentiated tumor 9-16
• If gross tumor would be left using the shaving
  technique wild field resection should be
  performed .

97

• RLN enveloped paralyzed it should be sacrificed
  .
• If it is the only functioning nerve and the tumor
  and the tumor can be dissected off this should be
  done

98
Superficial invasion can be shaved but direct
extension into the lumen sleeve or wedge
resection and primary anastomosis
99

• Superficial thyroid cartilage shave resection
• Hemilarynx vertical partial laryngectomy
• Anterior larynx hemilaryngectomy And
  reconstruction
• Cricoid and bilateral laryngeal involvement
  total laryngectomy

100
Postoperative RT and iodine is indicated
101
Regional lymph node

• In all patient pericapsular and paratracheal
  node need to be removed routinely
• Overt node in these area sup. Mediastimun and
  lateral neck exploration

102
Papillary carcinoma

• Clinical node 20-25
• Pathological node 30-79
• It has no adverse effect on prognosis
• Extracapsular extension does not appear to have
  an ominous prognosis

103
Follicular carcinoma

• Very rare lt 10 clinically 20 pathologically
• Neck dissection are performed only for overt
  metastasis

104
Hurthle cell carcinoma

• 30 lymphatic metastasis
• Functional neck dissection should be performed
  when disease is encountered

105
Medullary carcinoma

• Metastasis 50 63
• Prophylactic paratracheal , superior mediastinal
  and lateral neck dissection
• Or positive node in mediastinum and lateral
  neck dissection is performed

106
Follow -up
107
Well-differentiated tumor

• Become hypothyroid and after 4-6 week radioiodine
  scan
• Any residual tissue I ablation
• In overt local or regional remnant distant
  metastasis should be used
• Further 6 and 12 months scan and then every 2
  year
• Serum thyroglobulin every 6 months

108
Medullary carcinoma

• Calcitonin level every 3 months ( in first year
  )
• Every six months there after
• High calcitonin level full metastatic work up
  CT MRI of the neck and octreotide scan
• No overt disease neck dissection and if it done
  before RT to neck

109
Postoperative RT

• Residual and inoperable disease or cancer that
  has undergone anaplastic transformation
• 50 Gy
• RT appears more effective than radioactive iodine
  in treating local recurrence in WD cancer
• I radioactive is the treatment of choice for
  distant metastasis
• RT is the treatment of choice in anaplastic
  carcinoma

110
Role of chemotherapy

• Most disappointing results

111
Postoperative thyroid hormone

• Total thyroid ablation T4 supplement
• It is useful in controlling any microscopic
  residual WD thyroid cancer that may have been
  left locally , regionally or distantly

112
Prognosis

• Low risk patient 1-2 MR
• High risk patient 40 50
• Hereditary sporadic cancer have similar
  survival ( 82 at 5 year )
• Anaplastic cancer has a dismal survival
• Early stage medullary good prognosis