thyroid carcinoma final [part 2]
TRANSCRIPT
THYROID TUMORS
Dr Lohith S DNB Resident Department of General Surgery Bhagwan Mahaveer Jain Hospital, Bangalore
NORMAL ANATOMY OF THE THYROID GLAND:
MICROSCOPIC PICTURE OF THE THYROID GLAND:
TYPES OF THYROID CANCER: Primary: Follicular epithelium – well differentiated papillary follicular Follicular epithelium – undifferentiated Anaplastic Parafollicular cells Medullary Lymphoid cells lymphoma Secondary : metastatic
THE CAUSES:Radiation exposure to thyroid gland in child hood
Family history : a 4 to 10 fold increased risk of well differentiated thyroid cancer in 1st degree relatives with this neoplasia
THE CAUSES:Iodine: Iodine-deficient diets may
lead to increase the TSH level and considered goitrogenic
Thyroiditis: (Hashimoto's Disease) may develop into a form of cancer called lymphoma.
TNM STAGING OF THYROID CANCER:
EVALUATION OF THYROID TUMOR: History:Age and GenderRapid increase in size, dyspnea,
dysphagia and hoarseness of voiceFamily History Of thyroid cancerHistory Of irradiation On Examination:Firmness, Mobility, Size and adherence
to surrounding structuresPresence of lymphadenopathy
INVESTIGATIONS:FNAC: The accuracy cytological diagnosis
from FNA ranges from 70% to 97% and highly dependent on the skill of the physician and the cytopathologist interpreting it.
INVESTIGATIONS:Ultrasound: For the presence of malignant assosciations Microcalcification Irregular margins Hypervascularity Extra glandular extension
INVESTIGATIONS:
Ultrasound guided FNAC : Decrease the nondiagnostic specimen Increase the sensitivity and specificity Avoiding vascular structures
INVESTIGATIONS:Radionuclide Scan:To determine the functional status of the
nodule Hypofunctional “cold nodule”ule”Serum Calcitonin level:Routine measurement of calcitonin level
advocated by some authors to Diagnose Medullary cancer is unknown
PAPILLARY THYROID CANCER: Cystic or Solid Slow growing Young females Female: Male is 3:1 Most common (80-85%) Local recurrence rate of papillary carcinoma is
more while distant metastasis is less Spread through lymphatic Multicentric-local recurrence rate of pappilary
carcinoma is more while distant metastasis is rare. Hugely non encapsulated
Most common risk factors : Radiation Family history FAP Iodine excess
Presentations: Nodule in thyroid Dysphagia Dysphonia Lymphnode enlargement
PAPILLARY CANCER
Typical papillary projections and empty (orphan annie-eyed) nuclei
Orphan annie nuclei: large amount of chromatin present in nucleus makes it transparent
PSAMMOMA BODIES Psammoma bodies (PBs) are concentric
lamellated calcified structures, observed most commonly in papillary thyroid carcinoma (PTC), meningioma, and papillaryserous cystadenocarcinoma of ovary but have rarely been reported in other neoplasms and nonneoplastic lesions.
CLINICAL PRESENTATION:Incidental as a small occult tumor <1cm (papillary
microcarcinoma)Mass in the Neck the commonest way papillary cancer presentsGlands in the Side of the NeckThe spread to local glands (sometimes called
erroneously "lateral aberrant thyroid"). Distant Spread Spread to lungs or bone is seen but when it
occurs unlike most other cancers, cure is possible.
Common mode of spread: lymphatics
Most common organ of distant metastasis: lung
THE FOLLICULAR CANCER:It is unifocal(local recurrence is less)thickly encapsulated and shows
invasion of both capsule and blood vessels
Spread by the blood stream and rarely through lymphatic
It is unusual tumor (5 -10%)
RISK FACTORS: iodine deficiency Family history radiation
PRESENTATION: Already existing swelling growing in size Nodules Dysphagia Dysphonia
MOST COMMON HEMATOGENEOUS SPREAD IS TO SKULL (USUALLY TO OCCIPUT)CAUSING PULSATILE SECONDARIES.
CLINICAL PRESENTATION:As a single lump in the thyroid: This is the common mode of presentation. As pain in a bone or a spontaneous
fracture: in case of metastases to bone through the
blood stream
COMPARISON:
Non capsulated Multicentric Slow-growing
Iodine excess Usually lymphatic
route of spread Distant metastasis
to lung
Encapsulated Unifocal Present as rapid
increase in size Iodine deficiency Usually
hematogenous route of spread
Distant metastasis to occiput
Papillary Follicular
THE PROGNOSIS IN DIFFERENTIATEDTHYROID CARCINOMA: The two dominant factors are the age at
the diagnosis and the presence of distant metastases.
Recent several scoring systems based on
multifactorial analysis of risk factors have been advise
Most important to determine the prognosis is
STAGE OF CARCINOMA.
Low risk High risk
Patient age < 45 y > 45 y Tumor size < 4.0
cm > 4.0 cm
Extrathyoidal extension
absent present
Distant metastases
absent present
High tumor grade
absent present
DEPENDING OF INVASION
<1cm Noncapsular
invasion No blood vessel No lymphnode
invasion
>1cm Capsular invasion Blood vessel
invasion Lymphatic invasion
MICROINVASIVE INVASION
THE TREATMENT OF WELL DIFFERENTIATED THYROID CANCER:
It Consists of a three- pronged attack :
Thyroid Surgery Radioactive iodine therapy Drug - Thyroxine therapy
SURGERY: Acceptable surgical procedure to remove
thyroid tumor include Ipsilateral lobectomy Near total thyroidectomy Total thyroidectomy The recent American Thyroid Association
Guide lines recommended for more aggressive (total thyroidectomy ) for well differentiated thyroid carcinonoma
USUALLY WE FOLLOWFor Papillary Thyroid Carcinoma microinvasive –Total thyroidectomy >near total invasive - Total thyroidectomy
o For Follicular Thyroid Carcinoma microinvasive –hemithyroidectomy invasive - Total thyroidectomyIf lymphnodes are involved ipsilateral modified radical neck dissection is done.
SURGERY : With a 20-year follow up the incidence of
local recurrence with unilateral resection was (14%),whereas, for bilateral resection it was (2%)
For gross involvement of trachea or esophagus resection of these structures with reconstruction
ONE OF THE FEATURE OF PAPILLARY THYROID CARCINOMA IS CYST In case of cyst-aspiration is done
simple /benign
3 times re-aspired
If it still recurs then excision is done
RADIOIODINE THERAPY:The Indications: 1.After Surgery to destroy any residual
thyroid cancer cells or residual normal thyroid tissue.
2.To treat thyroid cancer that has spread to the lymph nodes, lungs or bones.
3.To treat thyroid cancer recurrence after initial treatment by surgery or previous radioactive iodine or both.
RADIOIODINE THERAPY: Recent American thyroid association
guide lines recommended radioiodine ablation for:
Pt. with stage III or IV disease All Pt. with stage II disease <45 yrs or > 45 yrs Selected Pt. with stage I disease those
with: large tumor ( >1.5 cm ) multifocality residual disease nodal metastasis
THYROXIN THERAPY : Recent meta-analysis supported the
efficacy of TSH suppression in preventing adverse clinical effect
High risk pt. are maintained at TSH level below 0.1 mU/ L
Low risk pt. TSH level at or below the normal range (0.1- 0.5 mU/ L)
THYROXIN THERAPY :The degree of thyroid suppression
is dictated by balancing the risk of recurrent thyroid cancer and subclinical thyrotoxicosis particularly the cardiovascular risks
Supression therapy is monitored by serum thyroglobulin(ideally should be <2ng/ml)
MEDULLARY THYROID CANCER: These are tumors of parafollicular (C
cells), which produce a hormone called calcitonin
Types of MTC : Sporadic MTC(common type) Familial MTC MEN 2A MEN 2B Familial Non- MEN
So a patient with Medullary Thyroid Carcinoma, rule out MEN Syndrome by ruling out PHEOCHROMOCYTOMA.
In MEN- pheochromocytoma is treated first even if it is benign
CLINCAL PRESENTATION:Sporadic MTC: asymptomatic thyroid mass that is
patient usually presents with a nodule. Familial MTC : patient may usually present with
diarrohea. screening stimulation test for calcitonin
or with molecular analysis ( detection of RET gene mutation)
ENZYMES SECRETED IN MEDULLARY THYROID CARCINOMACalcitoninCEAACTHPROSTAGLANDINSSEROTONIN(release is the reason for diarrohhea)
TREATMENT OF SPORADIC MTC:
C cells do not concentrate iodine so radioactive iodine is of no value in the management
Surgery is the only definitive therapy of MTC:
-Total thyroidectomy -Central node dissection - Ipsilateral modified radical neck dissection 1. if size of medullary thyroid carcinoma is more than 2
cm. 2. if LN are enlarged.
A TUMOR ERODING INTO THE CHEST WALL
TREATMENT OF FAMILIAL MTC:Based on the genetic test for the
mutation of RET geneSince different mutations in the
RET gene are associated with variable disease aggressiveness
this leading to individualized treatment of pt. with inherited MTC
MEN2A AND FMTC RX. :
Prophylactic thyroidectomy at age 5 to 6 years
MEN2B RX.:
Thyroidectomy during infancy that is around 6 months.
Surveillance is usually by yearly calcitonin assessment.
ANAPLASTIC CANCER OF THE THYROID:
It is a very aggressive tumor with a worst prognosis
A female to male ratio 1.5:1 and a mean age is 67 years
It is commonest in areas of endemic goiter where there is chronic iodine deficiency.
ATC commonly related to prior diagnosis of well differentiated thyroid cancer
CLINICAL PRESENTATION:a long-standing goiter that suddenly
increases in size. Local invasion lead to obstructive
symptoms, hemoptysis, dysphagia and hoarseness
At the time of Diagnosis 25 to 50 % of Patient have synchronous pulmonary metastases
ANAPLASTIC CARCINOMAMost common mode of spread is- local infiltration.
Consistency- woody hardLife expectancy is 6 months.
A CT scan showing anaplastic cancer of the thyroid
A woman with anaplastic cancer of the thyroid
SURGICAL TREATMENT OF ATC:
In the majority of cases surgery is limited to an open biopsy to exclude lymphoma
Otherwise treatment usually involves total thyroidectomy with chemotherapy agents
Or we can go for palliative treatment like istemectomy or tracheostomy
RADIOTHERAPY AND CHEMOTHERAP:
External beam radiotherapy (EBRR) as been used with limited success to treat locally recurrent ATC
Doxorubicin is the single most effective chemotherapeutic for ATC
THYROID LYMPHOMA:Thyroid lymphoma is relatively rare
disease constituting <1% of all lymphoma and accounting for 2% of extranodal non- Hodgkin’s lymphoma
Female: Male ratio from 3:1 up to 8:1 Median age is seventh decade of life
CLINICAL PRESENTATION:
Local invasion : hoarseness, dyspnea with stridor, or dysphagia
Hypothyroidism in case of Autoimmune thyroiditis or Hashimoto’s thyroiditis
A 70 Y. old lady with diffuse large B cell lymphoma
TREATMENT :Primary treatment should be
EBRT combined with Chemotherapy regimen based on histopathological subtype of lymphoma
TREATMENT :Primary treatment should be
EBRT combined with Chemotherapy regimen based on histopathological subtype of lymphoma
Green LD et al, anaplastic thyroid cancer and 1ry thyroid lymphoma. J Surg Oncol 2006;94:725