Papillary and follicular thyroid cancerK. A. Ikram HussainFinal year M.B.B.S.

Papillary thyroid cancer

It is a relatively common well differentiated thyroid cancer

Accounts for 85% of all thyroid cancers It is more common in females than males In more than 50% cases in spreads to lymphnodes of

the neck

Aetiology Most thyroid cancers are sporadic It can be a complication of Hashimoto’s thyroiditis Familial and genetic syndromes are associated with thyroid

malignancies Cowden’s syndrome Gardner’s syndrome Carney’s syndrome Associated mutations: chromosomal translocations involving

RET proto-oncogene

Pathology

It is made of colloid filled follicles with papillary projections. In some cases calcific lesions are found called psammoma bodies Characteristic pale empty nuclei called Orphan Annie eye nuclei

are seen in some cases Can present as cystic lesions Can be multifocal involving both lobes Lymph nodes and Lungs are the usual sites of metastases

Psammoma bodies

Orphan Annie eye appearance

Clinical presentation

Young females of age group 20-40 years are commonly affected

Principal sign is a firm non tender nodule in thyroid area with a hard consistency and ill defined borders

Signs of hoarseness, tracheal and esophagal compression is present

Very often lymph nodes in lower deep cervical region are involved and thyroid may or may not be palpable.

Prognostic criteria

Investigations

Thyroid profile Ultrasound of thyroid and central neck Fine needle aspiration cytology of the nodule Serum thyroglobulin TSH suppression test

Immunohistochemisty findings

Carcinoembryonic antigen (CEA) negative Calcitonin negative Thyroglobulin positive Keratin positive

Treatment Total thyroidectomy After thyroidectomy, patients are given thyroid replacement therapy for approximately

4-6 weeks. Thyroid replacement is then discontinued, to induce a hypothyroid state and promote high serum thyroid-stimulating hormone (TSH) levels.

Approximately 4-6 weeks after surgical thyroid removal, patients may have radioiodine therapy to detect and destroy any metastasis and residual tissue in the thyroid

A diagnostic dose of radioiodine (131 I or123 I) is then given, and a whole-body scintiscan is performed to detect any tissue taking up radioiodine. If any normal thyroid remnant or metastatic disease is detected, a therapeutic dose of131 I is administered to ablate the tissue. The patient is then placed back on thyroid hormone replacement (levothyroxine) therapy.

Therapy is administered until radioiodine uptake is completely absent Long term surveillance: Thyroglobulin Prognosis:95% adults survive over 10 years

Complications due to surgery and radio iodine therapy Hypothyroidism Dysphagia Vocal cord paralysis Hypoparathyroidism Sialoadenitis because radioiodine is taken up by the salivary glands Pulmonary fibrosis in patients with large lung metastases Brain edema in patients with brain metastases (may be prevented by

glucocorticoid therapy) Permanent sterility and transient oligospermia or menstrual irregularities A small increase in the risk for leukemias or breast and bladder carcinomas

Factors affecting poor outcome

Large primary tumor Age > 45 years Male sex Lymph nodal metastases Distant metastases Multifocal disease Extra-thyroidal extension

Follicular carcinoma of thyroid

It is a well differentiated tumor and 2nd most common after papillary thyroid cancer

Incidence is 17% of cases Follicular adenomas are 20% malignant and 80%

benign

Aetiology

Follicular carcinoma usually arises in a multinodular goitre especially in a cases of endemic goitre.

It should be suspected when multinodular goitre starts growing rapidly

Pathology

Depending on invasion it is classified as Noninvasive Invasive refers to angio-invasion and capsular

invasion

Angioinvasion

Clinical presentation It can present as multinodular or solitary nodular goitre. The diagnosis is confirmed after an ultrasound scan reveals features of

malignancy like microcalcifications Metastasis in flat bones: when a patient with a thyroid swelling presents

with metastasis in the bone in the form of bony swelling or pathological fractures, a diagnosis of follicular carcinoma can be considered.

Common secondaries are flat bones like skull,ribs,sternum and vertebral column because flat bones retain red marrow for a longer time.

Clinical features of a secondary are: they are rapidly growing,warm, vascular and pulsatile.

Metastasis to bone

Treatment Treatment of primary: Total thyroidectomy is always preferred

Treatment of the metastasis: After total thyroidectomy a whole body scan is done to look for metastasis

in the bone. A single secondary can be treated with oral radioiodine therapy followed by radiotherapy depending on the response to treatment

Multiple secondaries are also treated with oral radio iodine.

Postoperative thyroxine: Postoperative period patient should receive thyroxine 0.3mg/day to

suppress TSH and to supplement thyroxine. Prognosis: 15% mortality in 10 years.

Summary

Characteristics Papillary carcinoma Follicular carcinomaAetiology Sporadic/irradiation Endemic goitreIncidence 60% 17%Age (years) 20-40 30-50Diagnosis Thyroid swelling with

lymphnode metastasisThyroid swelling with bony metastasis

Microscopy Orphan Annie eye nuclei,Psammoma bodies

Angioinvasion,Capsular invasion

Spread Lymphatic BloodInvestigation FNAC Frozen sectionTreatment of primary Subtotal/total

thyroidectomySubtotal/total thyroidectomy

Treatment of metastasis Functional neck dissection Radioiodine 131 iodine

Hurthle cell carcinoma

It is a variant of follicular cell carcinoma and more aggressive than follicular cell carcinoma

These tumors are defined by presence of more than 75% of follicular cells with oncocytic features.

Tumor contains sheets of eosinophilic cells packed with mitochondria They secrete thyroglobulin Even if hurthle cell adenoma is well encapsulated it is potentially

malignant. It does not take up iodine 131. hence less likely to respond to

radioablation. Mortality is high 20% in 10 years

Criteria to diagnose

Capsular or vascular invasion and distant metastasis Higher chance of spread to lymph nodes compared to follicular thyroid

carcinoma Higher chances of spread to distant sites tooTREATMENT:Total thyroidectomy is the treatment of choice.TSH suppression and follow-up is required regularly.

Follow up

Serum thyroglobulin- thyroid is the only organ which produces thyroglobulin. Levels greater than 1-2mg/ml in patients receiving replacement thyroxine therapy indicates presence of metastasis.

So serum thyroglobulin response to injected recombinant TSH is assessed every year.

Ultrasound or MRI scans of neck for localisation of residual or recurrent tumor