ANATOMY , EMBRYOLOGY NORMAL USG APPEARANCE AND VAROUS IMAGING FEATURES IN DIFFERENT THYROID PATHOLOGIES INVOLVING TIRADS

1. Dr Vaibhavi Patel
DNB Resident
Apollo hospital
Gandhinagar

2.  Single midline endocrine organ in the
anterior neck.
 Responsible for thyroid hormone production.
 lies in the visceral space completely
enveloped by pretracheal fascia (middle
layer of the deep cervical fascia).

3.  Extends from C5 to T1 vertebrae.
 It lies anterior to the thyroid and cricoid
cartilage of the larynx and the first five or
six tracheal rings.
 The thyroid is butterfly or "H"-shaped and is
composed of two lobes, each with a superior and
inferior pole.
 The superior pole is narrower than the inferior
pole.
 The lateral lobes are connected in the midline
by a narrow isthmus which is adherent to the
2nd-4th tracheal rings.
 SIZE : 4 cm in length (cranio-caudally).
 Average weight is 25 g.

4.  The ligament of Berry:
A posterior extension of the thyroid capsule
which attaches to the cricoid cartilage and
the upper tracheal rings.
It encloses a short segment of the recurrent
laryngeal nerve as it ascends in the tracheo-
esophageal groove.
it is an important surgical landmark during
thyroidectomies to avoid damaging the
nerve.

5.  Arterial supply :
 Superior thyroid artery (from the
external carotid artery)
 Inferior thyroid artery (from
the thyrocervical trunk)
• Venous drainage :
 Superior thyroid vein (drains to
the internal jugular vein)
 Middle thyroid vein (drains to the internal
jugular vein)
 Inferior thyroid vein (drains via plexus to
the brachicephalic vein)

6.  The thyroid gland develops from the proximal
primitive foregut between the first and
second pharyngeal pouches at the foramen
cecum, in the midline of the base of the tongue.
 During the 5th embryonic week, a diverticulum
forms at the foramen which inferiorly migrates
anterior to the body of the hyoid bone, curving
posterior and superiorly to reach behind the bone
before once more turning inferiorly and continuing
anterior to the larynx, forming the thyroglossal
duct.
 The tip of the duct bifurcates, forming the two
lobes of the gland.

7.  The parafollicular
cells (C cells)
responsible for
calcitonin
production are
derived from
separate tissue,
the
ultimobranchial
body, a small
diverticulum of
the fourth
pharyngeal pouch

8.  The normal thyroid gland has a homogeneous
appearance with medium echogenicity
 the capsule may appear as a thin
hyperechoic line
 each lobe normally measures
 length: 4-7 cm
 depth: < 2 cm
 isthmus < 0.5 cm deep
 volume (excluding isthmus, unless its
thickness is > 3 mm)
 10-15 mL for females
 12-18 mL for males

10.  lobar hemiagenesis
 Pyramidal lobe
 superiorly-projecting thyroid tissue from the
isthmus
 Thyroglossal duct cyst
 Ectopic thyroid tissue
 Lingual thyroid
 Accessory thyroid gland
 Zuckerkandles tubercle
 the gland may be supplied by a thyroidea ima
artery, which may replace the inferior
thyroid artery (3%)

11.  A rare anomaly defined by the congenital
absence of one of the thyroid lobes

12.  Superiorly-projecting thyroid tissue from the isthmus.
 longitudinal image (labeled CC) shows the pyramidal
lobe (open arrows) lying superior to, and contiguous
with, the normal isthmus.

13.  The most common type of congenital neck
cysts and pediatric neck masses.
 Typically located in the midline and are the
most common mid line neck mass in young
patients.
 Epithelial-lined cysts result from failure of
normal developmental obliteration of
the thyroglossal duct during development
(8th - 10th gestational week) and can thus
occur anywhere along the course of the
duct.
 The cysts can occur anywhere along the
course of the thyroglossal duct from
the foramen cecum to the thyroid
gland although infrahyoid location is most
common.
 Move on swallowing and tongue protrusion .

15.  located in a location other than the normal
position anterior to the laryngeal cartilages.
 Lingual : base of tongue (90%)
 sublingual: below the tongue
 prelaryngeal
 other sites, e.g. mediastinum (<1%),
intratracheal
 Congenital hypothyroidism is common in
patients with ectopic thyroid, requiring life-
long hormone replacement.

16.  Absent thyroid tissue in its normal location. Instead,
a well defined subcutaneous (superficial) echogenic
homogeneous structure is seen prelaryngeal
region.No focal nodules. It shows average vascularity
on applying colour Doppler.

18. Zuckerkandl tubercle (ZT) is a lateral projection from the
lateral thyroid lobe .
The remant of the lateral thyroid process.
An important anatomic structure that serves as a reliable
landmark for the recurrent laryngeal nerve in thyroid surgery.
the RLN passes immediately medial to it.

19.  Inflammatory conditions:
- Autoimmune thyroiditis-
- Infective thyroiditis
associated with PCP/PJP , fungal or MAC
- Drug Induced thyroiditis
- amiodarone, interferons, lithium and cytokines
- Post partum thyroiditis
Graves disease
De quervain thyroiditis ( subacute
granulomatous )
Sub acute lymphocytic throiditis
Hashimoto thyroiditis
Riedel thyroiditis

20.  also known as Basedow disease
 an autoimmune thyroid disease and is the most
common cause of thyrotoxicosis. Results from an antibody
directed stimulation of the thyroid-stimulating hormone (TSH)
receptor, with resultant production and release of T3 and T4
 a strong female predilection with an F:M ratio of at
least 5:1
 Typically presents in middle age.
 The combination of exophthalmos, palpitations, and
goiter is called the Merseburger (or Merseburg)
triad.
 Serology
 TSH: suppressed
 T4: elevated
 T3: elevated
 TSH receptor antibodies (TSI, TGI, TBII): positive

21.  Thyroid gland is often enlarged and can be
hyperechoic
 heterogeneous thyroid echotexture
 relative absence of nodularity in
uncomplicated cases
 hypervascular; may demonstrate a thyroid
inferno pattern on color Doppler - multiple
small areas of color flow seen diffusely
throughout the gland representing increased
vascularity and arteriovenous shunting.

22. The thyroid gland is
diffusely enlarged and
hypoechoic with a slightly
lobulated contour. Color
Doppler demonstrates a
diffusely increased
vascular flow in the
thyroid gland, a
phenomenon also known as
"thyroid inferno".
multiple small areas of
color flow seen diffusely
throughout the gland
representing increased
vascularity and
arteriovenous shunting.

23.  Form of self-limited subacute granulomatous
thyroiditis.
 usually preceded by an upper respiratory
tract viral infection such as
mumps, measles, coxsackie virus,
adenovirus, and influenza viruses.
 usually affects middle-aged females.
 a pain in neck along with symptoms and signs
of thyrotoxicosis including tachycardia, hot
flushes, heat intolerance and palpitations.
 short period of hypothyroidism followed by a
return of a euthyroid state in the majority of
cases.

24.  Poorly defined regions of decreased
echogenicity with decreased vascularity in
the affected areas.
 can be bilateral or unilateral.
 Thyroid gland size is mostly normal but can
occasionally be enlarged or smaller in size.

25.  Ultrasound of the right lobe of the thyroid
demonstrates an ill-defined irregular region of
heterogeneous hypoechogenicity without elevation
of flow on colour Doppler examination.

26.  silent subacute thyroiditis.
 recent onset of symptoms.
 painless-an absence of thyroidal pain or
tenderness.
 young women, especially in postpartum period
 gland is usually normal in size, or minimally
increased
 usually an early hyperthyroid state which returns
to normal, but may have a transient late
hypothyroid period
 elevated levels of thyroid peroxidase (TPO)
antibodies.
 elevated thyroglobulin antibodies

27.  known as lymphocytic thyroiditis or chronic
autoimmune thyroiditis- One of the most
common thyroid disorder.
 affects middle-aged females (30-50 year age
group with an F:M ratio of 10:1).
 Patients usually present with hypothyroidism +/-
goiter.
 There is often a gradual painless enlargement of
the thyroid gland during the initial phase with
atrophy and fibrosis later on in the course.
 Hashitoxicosis is the hyperthyroid phase of
Hashimoto's thyroiditis. It is caused by the
destruction of the thyroid follicles by an
inflammatory process that releases preformed
thyroid hormones into the serum

28.  Humoral- and cell-mediated autoimmunity to
the thyroid gland followed by lymphocytic
infiltration of the thyroid gland with lymphoid
follicles replacing thyroid follicles.
 Sero markers : antithyroglobulin antibodies and
thyroid peroxidase antibodies (TPO).
 Associations
 Turner syndrome
 Primary thyoid lymhoma
 Downs syndrome
 SLE
 Type 1 DM
 Rheumatoid arthritis
 Sjogren syndrome
 Primay billiary cirrhosis

29.  initial phase :
diffusely enlarged thyroid gland with a
heterogeneous echotexture
 chronic phase :
the glands may be atrophic and small
 The presence of hypoechoic micronodules (1-6
mm) with surrounding echogenic septations is
also considered to have a relatively high positive
predictive value – Pseudonodular or giraffe
pattern.
 color Doppler study :
normal or decreased flow
occasionally hypervascularity - thyroid inferno
the hypervascularity does not reflect
thyrotoxicosis , its more common in hypothyroid
hashimoto patients.
 prominent reactive cervical nodes may be
present, especially in level VI

30. Both lobes of the thyroid gland are of decreased size. heterogeneous
echogenicity with numerous minute hypodensities within that
represent tiny hypoechoic nodules. separated by fibrous echogenic
septa. increased vascularity on Doppler study.

32.  Very rare form of autoimmune thyroiditis
 considered as a manifestation of a wider
systemic disease with fibrosis of
the retroperitoneum,mediastinum as well as
lymphocytic infiltration of extraocular orbital
muscles, salivary and lacrimal glands.
 Related to IgG4 disease.
 Presentation : a painless thyroid mass that can
be rapidly growing. there may be symptoms from
local compression such as dysphagia or stridor.
 On examination, there is usually a goiter which
is fixed and hard, sometimes described as stony
or woody.
 Replacement of the thyroid gland with fibrotic
tissue which extending to the surrounding
tissues, unlike end stage hasimotos thyroiditis in
which fibrosis is confined to the capsule.-
Hardening of thyroid gland as a result.

33.  homogeneously hypoechoic with the poor
demarcation of the gland borders
 Due to the fibrotic invasion of the adjacent fat or
anatomical structures.
Very heterogeneous parenchyma markedly hypoechoic
micronodular wih thick echogneic septae marked as red arrow

34.  hyperplastic/colloid nodule/nodular hyperplasia: 85%
 adenoma
 follicular: 5%
 others: rare
 primary thyroid cancers (carcinoma)
 papillary: 60-80% of carcinomas
 follicular: 10-20%
 medullary: 5%
 anaplastic: 1-2%
 other malignancies
 thyroid lymphoma: 1%
 metastases to the thyroid: 1%
 SCC: rare
 others
 fat-containing thyroid lesions
 adenolipoma of the thyroid gland
 liposarcoma of the thyroid gland

35.  non-neoplastic benign nodules
 The vast majority of nodular thyroid disease.
 irregularly enlarged follicles containing abundant
colloid-can be cystic, may contain areas of
necrosis, hemorrhage and/or calcification.
 Ultrasound
 iso- to hypoechoic
 may have internal cystic or heterogeneous
change
 may have calcification
 multiple echogenic foci (of inspissated colloid)
with comet tail artifact

37.  commonly found benign neoplasm of
the thyroid consisting of differentiated
follicular cells.
 Difficult to differentiate from follicular
carcinoma on cytologic, sonographic or
clinical features alone.
 more commonly found in women.
 Increased incidence in regions in which the
diet is iodine deficient.
 5 times more frequent than follicular
carcinomas.

38.  thin peripheral halo (s/o fibrous capsule )1-3 cm.
 predominantly cystic or mixed cystic and solid
lesions.
 isoechoic or predominantly anechoic.
 can be homogenous or heterogeneous.
 absence of internal flow or predominantly
peripheral flow indicates is associated with
reduced probability of thyroid follicular
malignancy .
 cystic degeneration, hemorrhage, ossification,
calcification and fibrosis can be seen

40.  the most common malignancy of the thyroid
gland – 70 % of all thyroid neoplasms.
 frequently has nodal metastases at the time of
presentation.
 Affects middle-aged, with a peak incidence in
the 3rd and 4th decades.
 more common in women with an M:F ratio of
1:2.5
 Associations
 Gardner syndrome
 Cowden syndrome
 familial adenomatous polyposis

41.  Presentation - usually with a solitary
palpable thyroid mass.
 a tendency to metastasize early to local
lymph node- 50% of patients having nodal
involvement at presentation.
 usually to the ipsilateral jugular chain- the
mid and lower lymph node levels - levels III
and IV.
 multifocality is common.
 characteristic Orphan Annie eye nuclear
inclusions, and psammoma bodies on HPE.

42.  a solitary mass –
with an irregular outline,sepatations , thick
nodular walls, cystic components
located in the subcapsular region
demonstrating vascularity.
 Small punctate regions of echogenicity
representing microcalcifications- psammoma
bodies.
 Lymph node metastases- cavitating , cystic
 lateral aberrant thyroid - actually a lymph
node metastasis from papillary thyroid
carcinoma

44.  The second most frequent malignancy of
the thyroid gland.
 typically occurs in women and in an older
age group-40-60 years of age.
 Hematogenous spread much more common.
 Ultrasound
 lesions are typically hypoechoic
 usually lacks cystic change
 Cytology after fine-needle aspiration cannot
differentiate between a follicular thyroid
adenoma and a follicular thyroid carcinoma.
Surgical resection is necessary.

45.  A nodule of the thyroid gland shows
heterogeneous isoechogenicity with focal
nodular macrocalcification, less than 50% of
cystic change and a thin hypoechoic rim.

46.  accounts for 5-10% of all thyroid
malignancies
 sporadically and as a familial form.
 familial- multiple endocrine neoplasia type
II (MEN2) syndromes
(both MEN2a and MEN2b), von Hippel-Lindau
disease neurofibromatosis type 1
 arise from parafollicular C cells of the
thyroid.
 Produces calcitonin- Hormonal marker.
 calcification of both primary and metastatic
sites.
 Metastatic involvement may be seen in up to
50% at the time of presentation

47.  Punctate high echogenic foci resembling
calcification .
 within the primary thyroid lesion as well as
metastatic regional lymph nodes and distant
metastatic sites.
 Involved lymph nodes typically calcify.

48.  Hypoechoic, mildly irregular mass within
the left lobe of the thyroid gland
 which demonstrates internal flow and
calcification.

49.  a highly aggressive form of thyroid cancer.
 carries the worst prognosis.
 peak incidence in the 6th and 7th decades.
 patients may have a history of
concurrent multinodular goiter.
 More common in females.
 Patients tend to present late.
 Compressive symptoms of neighboring
structures are common.

50.  Ultrasound imaging of ATC: a hypoechoic
mass with invasion of the local structures
 can be associated with neck lymph node
metastases.

51.  Very rare <5 % of thyroid malignancies
 can be primary or secondary to lymphoma
elsewhere.
 typically presents between 50-70 years of age
 strong female predominance (M: F = 1:3).
 Typically, it presents as a rapidly enlarging goiter
with compressive symptoms and cervical
lymphadenopathy.
 approximately half of patients are euthyroid.
 Hashimoto thyroiditis is a major risk factor.
 diffuse large B cell lymphoma being the most
common
 non-Hodgkin lymphoma accounts for the vast
majority of thyroid lymphoma cases.

52.  Three patterns have been described:
nodular (hypoechoic mass),
diffuse (mixed echotexture),
mixed
 Calcifications are uncommon

53.  Transverse sonogram shows
the enlarged thyroid with
decreased heterogeneous
internal echoes (arrows)
The transverse sonogram shows the
presence of a hyperechoic portion (short
arrows) and microcalcification (long arrow)
within an extremely hypoechoic PTL lesion
Diffuse type Nodular type

54.  Metastases to the thyroid are an uncommon
cause of thyroid malignancy.
 the incidence is ~10%
 ost common sites of primary malignancy include
kidney
 renal cell carcinoma (considered most common)
 lung
 head and neck
 breast
 gastrointestinal tract
 esophageal cancer
 colorectal cancer
 gastric cancer
 skin
 malignant melanoma
 neuroendocrine tumor
 cholangiocarcinoma (rare)

55.  Metastases to the thyroid most commonly
have the following features :
 hypoechoic lesion with poorly circumscribed
margins (80%)
 no calcifications
 concurrent cervical lymphadenopathy (80%)

56.  Standardized scoring system for
reports with recommendations for
when to use fine needle aspiration
(FNA) or ultrasound follow-up of
suspicious nodules, and when to
safely leave alone nodules that are
benign/not suspicious.