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