THYROID CANCER - PAPILLARY CARCINOMA

BY: DR.FARIS MOHSIN AL-ABEEDI

Papillary carcinoma is a relatively common well-differentiated thyroid cancer. Papillary/follicular carcinoma must be considered a variant of papillary thyroid carcinoma (mixed form). Despite its well-differentiated characteristics, papillary carcinoma may be overtly or minimally invasive. In fact, these tumors may spread easily to other organs. Papillary tumors have a propensity to invade lymphatics but are less likely to invade blood vessels. Papillary carcinoma appears as an irregular solid or cystic mass in a normal thyroid parenchyma

CHARACTERISTICS OF PAPILLARY THYROID CANCER

*Peak onset ages are 30 to 50 years old.

*Papillary thyroid cancer is more common in females than in males by a 3:1 ratio.

*The prognosis directly related to tumor size. (Less than 1.5 cm [1/2 inch] is a good prognosis.)

*This cancer accounts for 85% of thyroid cancers due to  radiation exposure.

*In more than 50% of cases, it spreads to lymph nodes of the neck.

*Distant spread (to lungs or bones) is uncommon.The overall cure rate is very high (near 100% for small lesions in young patients).

CAUSES

About 80% of all thyroid cancers diagnosed in the United States are papillary carcinoma type. It is more common in women than in men. It may occur in childhood, but is most often seen in adults around the age of 45.

The cause of this cancer is unknown. A genetic defect may be involved.

Radiation increases the risk of developing thyroid cancer. Exposure may occur from:

*High-dose external radiation treatments to the neck, especially during childhood, used to treat childhood cancer or some benign childhood conditions.

*Radiation due to atomic bomb testing in the Marshall Islands and the 1986 Chernobyl nuclear disaster in the Ukraine, mostly in children.

*Radiation given through a vein (through an IV) during medical tests and treatments does not increase the risk of developing thyroid cancer.

EXAMS AND TESTS

If you have a lump on your thyroid, your doctor will order blood tests and possibly an ultrasound of the thyroid gland,

CT scan

If the ultrasound shows that the lump is bigger than 1.0 centimeter, a special biopsy called a fine needle aspiration (FNA) will be performed. This test helps determines if the lump is cancerous.

Thyroid function tests are usually normal in patients with thyroid cancer.

This CT scan shows a thyroid cancer tumor in the throat, encircling, narrowing, and displacing the windpipe (trachea).

SYMPTOMS

Thyroid cancer usually begins as a small lump (nodule) in the thyroid gland, which is located at the center part of the front of the neck.While some small lumps may be cancer, most thyroid nodules are harmless and are not cancerous.Most of the time, there are no other symptoms.

Micrograph of papillary thyroid carcinoma demonstrating prominentpapillae with

fibrovascular cores . H&E stain.

Micrograph showing that the papillae in papillary thyroid carcinoma are composed of cuboidal cells. H&E stain.

Micrograph (high power view) showing nuclear changes in papillary thyroid carcinoma (PTC), which include groove formation, optical clearing, eosinophilic inclusions and overlapping of nuclei. H&E stain

There are three types of thyroid cancer treatment:*Surgery

*Radioactive iodine*Medication

Surgery is done to remove as much of the cancer as possible. The bigger the lump, the more of the thyroid gland must be removed. Frequently, the entire gland is taken out.After the surgery, most patients should receive radioactive iodine, which is usually taken by mouth. This substance kills any remaining thyroid tissue. It also helps make medical images more clear, so doctors can see if there is any additional cancer.

If surgery is not an option, external radiation therapy can be useful.After surgery or radioactive iodine, the patient will need to take medication called levothyroxine sodium for the rest of their life. This replaces the hormone that the thyroid would normally make

Treatment

Most patients who had thyroid cancer need to a blood test every 6 - 12 months to check thyroid levels. Other follow-up tests that may done after treatment for thyroid cancer include:Ultrasound of the thyroid done in the first yearAn imaging test called a 

radioactive iodine

Other follow-up

( PROGNOSIS)

The survival rate for papillary thyroid cancer is excellent. More than 95% of adults with such cancer survive at least 10 years.

The prognosis is better for patients younger than 40 and for those with smaller tumors.

The following factors may decrease the survival rate:*Age over 45

*Cancer has spread to distant parts of the body*Cancer has spread to soft tissue

*Large tumor

DIFFERENTIAL DIAGNOSIS

De Quervain Thyroiditis

Goiter

, Goiter Nontoxic

, Goiter Toxic Nodular

Graves Disease

Hurthle Cell Carcinoma

Thyroid Lymphoma

Thyroid Nodule

, Thyroid Anaplastic Carcinoma

, Thyroid Follicular Carcinoma

, Thyroid Medullary Carcinoma