1. THYROID TUMORS

2. OUTLINE Introduction Epidemiology Aetiology Classification
Clinical features
Investigations
Treatment
Prognosis

3. Epidemiology US: 40 per 1,000,000 per year <1% of all malignancies
6 deaths per million deaths p.a

4. Aetiology Irradiation of the thyroid.atomic bomb expo
Heredity: RET oncogene (xsome 10) plays a significant role in the devt of papillary thyroid cancer. More common in childhood thyroid cancer. Others are C-myc, C-fos, C-ras, C-erb B2/neu. Mutated ras gene, implicated in follicular tumors. Point mutations in p53 gene (a tumor suppressor gene), common in most anaplastic thyroid cancers.
Sustained TSH stimulation
Nearness to volcanoes

5. Classification Benign Follicular adenoma Malignant Primary
Differentiated tumors of follicular origin
- Papillary ca
- Follicular ca
Differentiated of parafollicular origin
- Medullary
Undifferentiated / Anaplastic
Secondary
Metastatic

6. FOLLICULAR ADENOMA
Typically, discrete, solitary masses derived from follicular epithelium
Clinically, it may be difficult to distinguish from follicular hyperplasia or carcinoma.
They are usually not premalignant xcept in rare cases.
Usually non-functional tho some may produce hormones independent of TSH stimulation I.e toxic adenomas.

7. Pathology
Mutation in TSH receptor leading to clonal expansion of follicular epith
Macro: A solitary, spherical encapsulated lesion well demarcated from surrounding thyroid parenchyma.
Micro: Uniform-appearing follicles containing colloid
The integrity of the capsule is important in distinguishing it from a follicular Ca.

8. Features A unilateral painless mass Large masses = pressure symptoms.
Toxic adenomas = symp of hyperthyroidism
Appear as cold nodules on radionuclide scanning
Ultrasonography
Incisonal biopsy
Thyroidectomy to rule out malignancy.
PROGNOSIS is excellent, do not recur or metastasize.

9. Rare benign tumors
Dermoid cyst
Lipoma
Hemangioma

10. PAPILLARY CARCINOMA
Most common thyroid malignancy, approx 80% in Europe but abt 20% in Nigeria
The predominant thyroid ca in children, 75% and people previously exposed to radiation in the neck (85 – 90%).
Commoner in women, 2:1 male to female
Mean age at presentation is 20 to 40yrs.

11. Pathology
Usually hard and whitish and remain flat on sectioning with a blade, rather than bulging.
Hisologically, they exhibit papillary projections or mixed pattern.
Has chacteristic cellular features- pale abundant cyto, crowded nuclei (Orphan Annie cells).
Psammoma bodies may be present
Higher propensity for lymphatic spread and direct spread to contiguous structures. Haematogenous metastases is a late feature.

12. Clinical features Most patients are euthyroid.
A slow-growing painless mass in the neck.
Local invasion – dysphagia, dyspnea, hoarseness.
Enlarged ipsilateral cervical glands, infact may be more apparent than the pry lesion –the lateral aberrant thyroid.
Distant metastases in 1-15%

13. Diagnosis
FNAC
Radioiodine thyroid scans: Failure to take up radioiodine is xteristic (cold masses)
Thyroid antibody test
CT Sscan
MRI

14. TNM Staging TUMOR NODES METASTASES TX Primary cannot be assessed
T0 No evidence of primary
T1 Limited to thyroid < 1cm
T2 Limited to thyroid, >1cm but <4cm
T3 Limited to thyroid >4cm
T4 Extension to capsule, any size
NODES
NX Cannot be assessed
NO No regional node metastases
N1 Regional node metastases
METASTASES
MX Cannot be assessed
M0 No metastases
M1 Distant metastases

15. Management Unilateral lobectomy and isthmectomy
Total or near-total thyroidectomy for bilateral dx or high risk patient
Thyroxine mg daily to suppress endogenous TSH production
Radioiodine to tx metastases if detected by scanning
Thyroglobulin measurement to detect metastases post-op

16. Prognosis AGES Scale- Age, Grade, Extent of disease, Size of tumor.
Low risk = young, well diff tumor, no metastases, small pry lesion.
High risk =older, poorly diffd, local invasion, distant metastases, large pry lesion
MACIS Scale- distant Metastasis, Age at presentation, Completeness of original surgical resection, extrathyroidal Invasion, Size of lesion.
AMES- Age, Metastases, Extent, Size
DNA Ploidy

17. FOLLICULAR CARCINOMA
Accounts for about 20% of thyroid malignancies in Europe but abt 60% in Nigeria.
Iodine-deficiency – hyperplasia -- neoplasia
Female to male ratio is 3:1
Age at presentation is yrs.
Hurthle cell tumors are a variant of FC in which oxyphil cells predominate. Assd with poorer prognosis.

18. Pathology Usually solitary and encapsulated in 90%.
Haematogenous spread occurs more commonly. Lymphatic spread is a late fx, (<10%).
Histologically, numerous follicles are seen which may be devoid of colloid.

19. Clinical features
A solitary thyroid nodule with hx of rapid increase in size or hx of long standing goitre.
Usu painless but can become painful if haemorrhage into the nodule occurs.
Cervical lymphadenopathy is uncommon.
Distant metastases.
Rarely, features of thyrotoxicosis (<1%).

20. Management
Definite pre-operative diagnosis is difficult bcos FNAC is unable to differentiate a benign follicular adenoma from a carcinoma.
Px diagnosed by FNAC as having a follicular lesion should undergo thyroid lobectomy. Frozen section examination is done and diagnosed carcinomas shld have total thyroidectomy + radioactive iodine + Thyroxine

21. MEDULLARY CARCINOMA Accounts for about 5% of thyroid carcinomas.
Arise from parafollicular or C cells derived from neural crest, found majorly in the lateral parts of superior poles.
C cells secrete calcitonin wc has opposing action to PTH and lowers serum Ca levels. Also secretes serotonin, PGs, histamine, ACTH, somatostatin, bombesin, VIP.
C cell hyperplasia is a premalignant precursor.

22. Associations
May be familial (30%) or sporadic(70%). Familial dx occurs as part of other endocrinopathies.
NON-MEN MTC
MEN IIA or Sipple’s syndrome - MTC + Hyperparathyroidism + Phaechromocytoma
MEN IIB – MTC + Phaechromocytoma + Ganglioneuromatosis + Marfan’s syndrome

23. Pathology Located in middle to upper thyroid poles
Unilateral in about 75% of sporadic cases but with familial cases, 90% are bilateral.
Has chacteristic amyloid stroma
Immunohistochemistry for calcitonin is a diagnostic tumor marker. Also stain for carcinoembryonic antigen (CEA), histaminase and calcitonin gene-related peptide..
lymphatic spread occur initially before distant haematogenous occurs

24. Clinical fx A painful neck mass
Palpable cervical lymphadenopathy in 15-20%
Local invasion:
Diarrhea (VIP)
Cushing,s syndrome from ectopic ACTH production
Kidney stones
Hypertension

25. Management
Genetic screening for familial cases + estimation of serum calcitonin. Prophylactic thyroidectomy are offered.
Treatment = Total thyroidectomy and resection of involved lymph nodes.
In all cases b4 surgery, phaeochromocytoma must be excluded by measurement of urinary catecholamines.

26. ANAPLASTIC CARCINOMA
One of the most aggressive malignancies with few patients surviving 6mths beyond diagnosis.
Incidence is abt 1% in US, but 5% in Nigeria. Endemic goiter is a precursor.
Common in elderly women, 7th – 8th decade.

27. PATHOLOGY:
Growth is extremely rapid, local infiltration an early feature. Spreads by lymphatics and blood stream.
Microscopically, sheets of undifferentiated small or giant cells are seen.

28. CLINICAL FEATURES
elderly women with hx of lump in the neck which suddenly enlarged rapidly and became painful.
Associated dysphonia, dysphagia and dyspnea.
Tumor is hard and may be fixed to surrounding structures, may be ulcerated.
Palpable lymph nodes usually.
Evidence of metastases.

29. Mgt
Diagnosis is by FNAC- reveals giant and multinucleated cells. Incisional biopsy may be used to confirm the diagnosis.
TREATMENT
Radiotherapy
Debulking thyroidectomy
Chemotherapy wt Doxorubicin
PROGNOSIS: Poor. Mortality =100%. Survival rarely exceeds 6months even wt treatment

30. LYMPHOMAS Approx 1% of thyroid maligs.
Most are non-Hodgkin’s B-cell type.
Usually develop in patients with chronic lymphocytic thyroiditis (Hashimoto’s).
Px presents with features of anaplastic tumors, altho the rapidly enlarging mass is painless.
Diagnosis is suggested by FNAC, needle or open biopsy is necessary for definitive diag. Lymph nodde biopsy helps clarify.

31. Response to chemo is good
Response to chemo is good. CHOP- Cyclophosphamide, doxorubicin, vincristine and prednisolone.
Combined radiotherapy and chemo is recommended. Thyroidectomy is used to alleviate tracheal compression.
Prognosis is good if cervical nodes are not involved.

32. METASTATIC CA The thyroid gland is a rare site for metastases.
Most common metastatic tumor is a hypernephroma. Others include breast, lung, melanoma

33. Rare neoplasms
Fibrosarcoma
Teratoma
Sq. cell carcinoma
mucoepidermoid