Download - Malignant thyroid
MALIGNANT THYROID
Dr. Amna AkramCMH, Multan
Thyroid cancer is a cancer originating from follicular and parafollicular cells. These cells give rise to well-differentiated and anaplastic cancers.
CLASSIFICATIONPapillary carcinoma (60%)Follicular carcinoma (20%)Anaplastic carcinoma (10%)Medullary carcinoma (5%)Malignant lymphoma (5%)Hurthle cell carcinoma is a rare type, considered a type of follicular carcinoma.
ETIOLOGYPapillary carcinoma…Radiation exposure
Follicular carcinoma…endemic goitre, a result of TSH stimulation
Medullary carcinoma…mutation in RET proto-oncogene,multiple endocrine neoplasia-type 2A and 2B
Lymphoma…autoimmune thyroiditis
RISK FACTORSHx neck irradiation in childhood
Endemic goitreHashimoto’s thyroiditisHx of thyroid adenomaFamilial thyroid CACowden’s syndromeExposure to nuclear Fallout (Chernobyl)
PRESENTATIONHistory: Thyroid carcinoma most
commonly manifests as painless, palpable, solitary thyroid nodules. These are mostly discovered on routine palpation.
Age of the patient is important at time of presentation because solitary nodules are most likely to be malignant in pt.s older than 60yrs and in younger than 30yrs.
Hoarsness suggests recurrent laryngeal nerve and vocal fold paralysis.
Dysphagia may be a sign of impingement of the digestive tract
Heat intolerance and palpitations suggest autonomously functioning nodules.
PHYSICAL EXAMINATIONMalignant nodules are usually hard, fixed and non-tender
Firm cervical masses are highly suggestive of regional lymph node metastases.
INVESTIGATIONSTFTsFNAC with/without USG guidanceThyroid autoantibodiesMRI/CT -if limits of goitre cannot be determined
clinically -fixed tumors -haemoptysis - DO NOT USE IODINATED CONTRAST MEDIA
STAGING Tumor: TX: cannot be assessed TO: no evidence of primary T1: limited to thyroid, 1cm or less T2: limited to thyroid, >1cm but <4cm T3: limited to thyroid >4cm T4: extending beyond capsule,any size Lymph Nodes: NX: cannot be assesssed N0: no regional lymph nodes involved N1: regional node metastases
Metastases: MX: Cannot be assessed MO: no metastases M1: metastases presentStage Under 45 years over 45 YearsI Any T, any N,MO T1, N0, M0II Any T, any N,M1 T2,N0,M0 or
T3,N0,M0III T4,N0,M0 or any
T,N1,M0IV any T,any N, M1
WELL-DIFFERENTIATED THYROID TUMORS
Papillary carcinomaFollicular carcinoma
Because they arise from follicular epithelium and take up radioactive iodine.
PAPILLARY CARCINOMA It tends to occur in young age group (30-
40yrs) and in females. It spreads through lymphatics. Histologically, tumor shows papillary
projections and pale empty nuclei (orphan Annie-eyed).
It is usually bilateral and never encapsulated. It has good prognosis Lateral aberrant thyroid is a metastatic
tumor in cervical lymph node from occult papillary carcinoma.
FOLLICULAR CARCINOMA It is more aggressive than papillary
carcinoma It spreads via blood as it invades capsule and
vessels. Hurthle cells tumor is a variant on
follicular CA, in which tumor contains sheets of eosinophilic cells pacled with mitochondria, which are derived from the oxyphilic cells of the thyroid gland.
- It is different from follicular CA in that they are more often multifocal and bilateral, usually do not take up radioactive iodine, and are more likely to metastasize to local nodes and distant sites and with a higher mortality rate.
TREATMENT OF PAPILLARY AND FOLLICULAR CARCINOMA Post operatively, thyroxine therapy is
avoided for 3 weeks, that leads to elavation of TSH levels (TSH is necessary for uptake of radioactive iodine by residual or metastases of thyroid carcinoma)
Surgical: Total thyroidectomy -If there is clinical involvemnet of
cervical Lymph nodes, then Neck Dissection should also be carried out.
Follow up with thyroglobulin level and whole body thyroid scan
Treat the recurrence or metastasis with
radioactive iodine Life long thyroxine therapy -Thyroxine 200ug, daily ( to provide
replacement of thyroxine and to suppress TSH which can cause recurrence)
PRE-REQUISITES FOR FULL BODY THYROID SCAN It is necessary to ablate all normal thyroid
tissue, or else it will uptake all the radioactive material and residual or metastases will be difficult to detect
TSH levels should be adequate Thyroxine therapy should be stopped for 6
weeks T3 should be given to the patient during this
time period, to decrease the period of hypothyroidism and should be discontinued for 2 weeks before scan to let TSH levels raise.
MEDULLARY CARCINOMA
Arise from parafollicular cells derived from neural crest cells.
Calcitonin and carcinoembryonic antigen is produced by these tumors and can be used as tumor markers
Familial cases occur in children and young adults while sporadic cases occur at any age
It is associated with pheochromocytoma and hyperparathyroidism in MEN-2A mutation.
TREATMENT Total thyroidectomy along with bilateral
central lymph nodes dissection If large tumor or positive central lymph
nodes….modified radical neck dissection Rule out pheochromocytoma by measuring
urinary catecholamine before doing thyroidectomy. If pheochromocytoma present, it should be operated on first
If Hypercalcemia present… only obvious enlarged parathyroid glands should be removed
If normocalcemia…when a normal parathyroid cannot be maintained on a vascular pedicle, it should be removed and then auto transplanted to the forearm.
If RET mutation carriers…Prophylactic
thyroidectomy is indicated - before age of 6 years in MEN2A
patients - before age of 1 years in MEN2B
patients If calcitonin raised and suggests
carcinoma… prophylactic central neck dissection is done.
ANAPLASTIC CARCINOMA More aggressive Treatment : All forms of treatment have dissappointing
outcome If tumor confined to thyroid ( very rare) ,
Then total thyroidectomy should be carried out
External beam radiotherapy has some role If tracheal obstruction present…
isthmusectomy is also done
LYMPHOMA OF THYROID Follows autoimmune thyroiditis (Hashimoto’s
thyroiditis)
Treatment:
Stage I and II … Radiotherapy Stage III and IV…chemotherapy
POST OPERATIVE COMPLICATIONS
Hemorrhage Reespiratory obstruction Tracheomalacia Recurrent laryngeal nerve palsy Thyroid insufficiency Thyrotoxic crisis Hypocalcemia (parathyroid insufficiency) Wound infection Hypertrophic scar or keloid Stitch granuloma
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