Thyroid gland enlargement

1. Thyroid Gland Enlargement
• UNZA School of Medicine
• 7th Year Students Tutorial
• Prof BFK Odimba
• MD MTD MPH MMED-CH MSC Ph.D

2. Introduction
• Commonest clinical presentation of thyroid
disorders
• At any age, predomominently in the Adult
• Any sex, predominently in the Female
• Clinical concern: Benign? or malignant?
• Management: Medical? Surgical?
• Neck Surgery: Among the most risky
procedures

3. Prerequisites
• Embryology, Anatomy, Physiology
• History Taking
• Physical Examination
• Appropriate Investigations
• Variety of Aetiologies
• Variety of Prognosis

4. Topics
• Embryology, Anatomy, Physiology
• Thyrotoxicosis and Hyperthyroidims
• Inflammatory Diseases of the Thyroid gland
• Cancers of the Thyroid Gland

5. Surgical Embryology/Anatomy
• 1st and 2nd pharyngeal pouches >Median entodermal
downgrowth
• 4th pharyngeal pouches>Ultimobranchial bodies during
migration caudally.
• Two lobes below the cricoid cartilage with central isthmus.
Possibility of pyramidal lobe
• Congenital abnormalies: foramen caecum, ectopic thyroid
(lingual thyroid , mediastinal thyroid,) thyroglossal cyst.
• 15-25 g, vascular organ, superior, inferior, isthma arteries
• relationship+++: trachea, laryngeal nerves, carotid vx,
jugular veins, lymphatics, parathyroid glands

6. Surgical Physiology
• Synthetises, stores and secretes hormone thyroxine (T4),
and triodothyronine (T3)
• Using GI iodine + tyrosine in thyroglobine
>monoiodotyrosine (MIT) and diiodtyrosine (DIT)
• MIT+DIT> T4 and T3 stored initially in the colloid of
gland
• Hydrolysis of the thyroglobulin, and T3 secreted into
plasma proteins.
• T3 :euthyroid condition: Extrathyroidal conversion of T4
toT3
• Negative Feed back : TRF, TSH, thyroid hormones

7. Evaluation of the thyroid gland
Surgical disorders
• History taking+++
• Physical examination++++(palpation)
• Thyroid function tests depend on clinical situation
• T3, T4, TSH superior to PBI and BEI (independent from
exogenous iodine)
• Serum T4: best screening for euthyroidism excepted if
change in protein binding (e.g pregnancy): > T3RUXT4=
normal
• Serum T3 (radioimmunoassay) to order if suspicion of
hypertyroidism and TSH if suspicion of hypothyroidism
• Ultrasound
• Isotope I 131+++

8. Hyperthyroidism (Thyrotoxicosis)
Aetiological Factors
• Graves Disease: diffusely hypersecreting
goiter+++
• Plummer Disease: Mono or multinodular
toxic goiter+++
• Rare causes: Molar pregnancy, TSH-
secreting pituitary tumours, Strumovari,
Thyroiditis

9. Hyperthyroidism Symptoms and signs
• The clinical findings are those of hyperthyroidism
and those related to the underlying cause
• Increase of levels of thyroid hormone in the bloodstream:
thyrotoxicosis: . Nervousness, weight loss with increased
appetite, heat intolerance, increased sweating, muscular
weakness and fatigue, increased howel frequency,
polyuria, menstrual irregularities, infertility.goiter,
tachycardia, warm moist skin, thyroid thrill and bruit,
cardiac flow murmur ; gynecomastia.. Skin warm, thin,
moist, hair fine. Achilles reflex time shortened
• Diffuse or nodular goiter

10. Hyperthyroidism Symptoms and signs (cont.)
• Hypersensibility (Graves Disease: autoimmune): .
Eye signs : staring, lid tag, exophthalmos; pre-tibial
mixoedema
• Iodine uptake, T3, T4, T3 resin uptake all
increased. TSH absent or simply reduced. T3
suppression test abnormal.
• Some times thyrotoxicosis described with a normal
T4 concentration, normal or elevated radioiodine
uptake, and normal protein binding but with
increased serum T3 by RIA (T3 toxicosis).

11. Hyperthyroidism Symptoms and signs
(cont.2)
• A history of medications is important
• Certain drugs and organic iodinated compounds
affect some thyroid function tests.
• Iodine excess may result in either iodine-induced
hypothyroidism or iodine-induced
hyperthyroidism
• In these difficult-to-diagnose cases, 2 additional
tests are helpful : the T3 suppression test and the
thyrotropin-releasing hormone (TRH) test.

12. Hyperthyroidism Symptoms and signs
(cont.3)
• In the T3 suppression test, hyperthyroid patients
fail to suppress the thyroidal uptake of radioiodine
when given exogenous T3.
• In the TRH test, serum TSH levels fail to rise in
response to administration of TRH in hyperthyroid
patients.
• Others findings include low serum cholesterol,
lymphocytosis, and occasio-nally hypercalcemia,
hypercalciura, or glycosuria.

13. Hyperthyroidism Symptoms and signs
(cont.4)
• Pseudothyrotoxicosis is occasionally seen in
critically ill patients and is characterized by
increased levels of T4 and decreased levels of T3
due to failure to convert T4 to T3.
• Thyrotoxicosis associated with toxic nodular
goiter is usually less severe than that associated
with Graves.yroid acropathy.

14. Hyperthyroidism Symptoms and signs
(cont.5)
• If left untreated, thyrotoxicosis causes progressive
and profound catabolic disturbances and cardiac
damage. Death may occur in thyroid storm or
because of heart failure or severe cachexia.
• Differential Diagnosis: many diseases+++
• anxiety neurosis, heart disease, anemia,
gastro-intestinal disease, cirrhosis,
Tuberculosis,s myasthenia and other
muscular disorders, menopausal syndrome,

15. Hyperthyroidism: differential diagnosis
– Pheochromocytoma, primary ophthalmopathy,
and thyrotoxicosis factitia
– May be clinically difficult to differentiate from
hyperthyrodism.
– Differentiation is especially difficult when the
thyrotoxic patient presents with minimal or no
thyroid enlargement.
– Interest of other investigations and tests and
good and repeated history taking and physical
examination

16. Thyroid Inflammatory Diseases
• Thyroiditis
– Acute
– Subacute and chronic
– The swelling of the neck is not always present

17. Thyroid Benign Tumours
• Adenomas
• Cystic tumours

18. Malignant Thyroid Tumours
(MTT)
• Essential diagnosis
• Investigations
• Types
• Management

19. MTT/Essential of Diagnosis
• . History of irradiation to the neck in some patients
• . Painless or enlarging nodule, dysphagia, or
hoarseness.
• . Firm or hand, fixed thyroid nodule ; cervical
lymphadenopathy. . Normal thyroid function ;
nodule stippled with calcium (x-ray),
• Cold (radioiodine scan), solid (ultrasound) ;
positive or suspicious ccyytology .

20. MTT Aetiological factors
• Various tumour behaviour, Some slow, others fast
• Cause unknown: Main factor irradiation to the neck in
some patients: persons who received low-dose(6.5-2000
rads) therapeutic radiation to the thymus, tonsils, scalp, and
skin in infancy, childhood, and adolescence have an
increased risk of developing thyroid tumors.
• Both children and adults up to 50 years of age who were
exposed to the atomic blast at Hiroshima had an increased
incidence of benign and malignant thyroid tumors.
• The incidence of thyroid cancer increases for at lest 30
years after irradiation.

21. Types of Thyroid Cancer: Papillary
adenocarcinoma
• Accounts for 85 of cancers the thyroid gland.
• The tumor usually appears in early adult life
• Solitary nodule that then spreads via
intraglandular lymphatics within the thyroid gland
and then to the subcapsular and pericapsular
lymph nodes.
• Eighty percent of children and 20 of adults
present with palpable lymph nodes.
• The tumour may metastasize to lungs or bone.

22. Types of Thyroid Cancer: Papillary
adenocarcinoma2
• Microscopically, it is composed of papillary
projections of columnar epithelium.
• Psammoma bodies are present in about 60% of
cases. A mixed papillary-follicular variant of
papillary carcinoma is sometimes found.
• The rate of growth may be stimulated by TSH.

23. Types of Thyroid Cancer: Follicular
Adenocarcinoma :
• Accounts for approximately 10 of malignant
thyroid tumors.
• Appears later in life than the papillary form and
may be elastic or rubbery or even to contain
colloid on gross examination
• Microscopically, may be difficult to distinguish
from normal thyroid tissue and may metastasize to
the regional lymph nodes

24. Types of Thyroid Cancer: Follicular
Adenocarcinoma2
• May also metastase to the lungs, skeleton, and
liver.
• Metastases from follicaular carcinomas may
appear 10-20 years after resection of the primary
lesion and may follow a relatively benign course,
• The prognosis is not as good as with the papillary
type

25. Types of Thyroid Cancer: Medullary
Carcinoma
• Accounts for approximately 2-5 of malignant tumors of
the thyroid.
• It contains amyloid and is a solid, hard, nodular tumor that
takes up radioiodine poorly.
• Medullary carcinomas arise from cells of the
ultimobranchial bodies, which also secrete calcitonin.
• Familial occurrence of medullary carcinoma associated
with bilateral pheochromocytoma and hyperparathyroidism
is known as Sipple s syndrome or type II multiple
endocrine adenomatosis.

26. Types of Thyroid Cancer:
Undifferentiated Carcinoma :
• This rapidly growing occurs principally in women
beyond middle life
• Accounts for 3 of all thyroid cancers. On
occasion, this lesion evolves from a pa-pillary or
follicular neoplasm.
• It is a solid, quickly enlarging, hard, irregular
mass diffusely involding the gland and invading
the trachea, muscles, and neurovascular structures
early.

27. Types of Thyroid Cancer:
Undifferentiated Carcinoma2
• The tumor may be painful and somewhat tender, may be
fixed on swallowing, and may cause laryngeal or
oesophageal obstructive symptoms.
• Microscopically, the cells are anaplastic, varying from
small to large or multinuclead, and undergo frequent
mitoses.
• Cervical lymphadenopathy is occasionally present, but
pulmonary metastases are more common. Local recurrence
after surgical treatment is the rule. External radiation
therapy is helpful in controlling the local process. The
prognosis is poor, and radioiodine therapy is ineffective .

28. Treatment of Thyroid Cancer
• Diffentiated thyroid carcinoma is operatively
removed.
• For papillary carcinoma, total lobectomy, nearly
total thyroidectomy, or total thyroidectomy are
acceptable operations and are followed by a 10-
year survival rate of of 80
• Subtotal or partial lobectomy is contraindicated,
because the incidence of tumor recurrence is
greater and survival is shorter.

29. Treatment of Thyroid Cancer2
• Total thyroidectomy is recommended by the author for
papillary(1.5 cm), follicular, and medular carcinomas if the
operation can be done without producing permanent
hypoparathyrodism or injury to the recurrent laryngeal
nerves.
• Total is preferred over subtotal thyroidectomy, because of
the high incidence of multifocal tumor within the gland, a
clinical reccurence rate of about 7 in the contralateral
lobe it is spared, and the ease of assessment for recurrence
during follow-up examinations.

30. Treatment of Thyroid Cancer3
• A conservative neck dissection preserving the
sternocleidomastoid muscle is performed if lymph
nodes are grossly involved.
• If extensive infiltrating tumor is present, a more
radical neck dissection may be necessary.
• All thyroid tumors must be studied by frozen
section during the operation to help plan the best
procedure.

31. Treatment of Thyroid Cancer4
• Medullar carcinoma has such a high incidence of
nodal involvement that concomitant or interval
prophylactic neck dissection is usually justified,
especially if serum calcitonin levels remain
elevated after thyroidectomy.
• Metastic deposits of follicular and papillary
carcinoma should be treated with 131 I after
total thyroidectomy or thyroid ablation with
radioactive iodine.

32. Treatment of Thyroid Cancer5
• All patients with thyroid cancer should be
maintained indefinitely on suppressive doses of
thyroid hormone.
• For following-up, it is helpful to measure serum
levels of thyroglobulin (a tumor market for
differentiated thyroid cancer), which are usually
increased in patients with residual tumor after total
thyroidectomy.

33. Treatment of Thyroid Cancer6
• For undifferentiated carcinoma, malignant
lymphoma, or sarcoma, the tumor should be
excised as completely as possible and then treated
by radiation and chemotherapy. Doxorubicin
(Adriamycin), vincristine, and chlorambucil are
the most effective agents.
• Carcinomas of the kidney, breast, and lung and
other tumors sometimes metastasize to the thyroid,
but they rarely present as a solitary nodule