Hürthle Cell Cancer: Causes, Symptoms and Treatment

Palpable enlargement of the thyroid, as well as the presence of a single nodule (or several), should raise suspicion of thyroid pathology. Among these, the different follicular thyroid carcinomas.

Written and verified by the doctor Mariel Mendoza.

Last update: 16 November, 2022

Hürthle cell cancer is a tumor of the thyroid gland. It can be benign in behavior or, to a lesser extent, malignant when it invades neighboring tissues or spreads to other organs.

This tumor originates from the oncocytes of the thyroid gland. Hürthle cell cancer is usually asymptomatic, but may cause visible growth of the thyroid. Its treatment is surgical removal, so a certain diagnosis is necessary.

Origin of Hürthle cell cancer

Hürthle cell cancer is named after Hürthle, who, in 1984, first described the disease with the theory that it comes from the C, or parafollicular, cells of the thyroid gland.

Later, in 1898, Askanazy described the oxyphilic cells and, in 1919, it was Ewing who determined that the tumor came from the follicular cells of the thyroid gland. Thus, Hürthle cell cancer is also called “oxyphilic tumor”, “oncocytoma”, “mitochondrioma” or “Askanazy cell tumor”.

Hurthle cells are large and polygonal, characterized by acidic-prone cytoplasm, fine granules containing numerous mitochondria, and a large, darkly colored nucleus.

A type of thyroid cancer

Hürthle cell cancer is a cytologic variant of follicular thyroid carcinoma, but more aggressive. It’s considered the most aggressive because there’s greater lymphatic involvement leading to lymph node spread or metastasis, in addition to hematic spread. On the other hand, they usually have a poor response to radioiodine therapy.

Askanazy cell tumor represents 3 to 4% of all thyroid cancers and 25% of follicular carcinomas. In the literature, it’s considered an intermediate grade tumor, because 20-33% of Hürthle cell cancer has malignant behavior evidenced by invasive growth and the ability to metastasize at a distance.

The incidence of Hürthle cell cancer is low

Experts point out that Hürthle cell cancer is rare and its peak incidence is between 50 and 70 years of age. It’s also more frequent around the age of 75 years, the ratio of women to men is 3:1.

The only treatment is surgical. Thus, a subtotal or total thyroidectomy is performed. The prognosis depends on the degree of invasion.

Initially asymptomatic

Hürthle cell cancer is usually asymptomatic. It usually produces no symptoms until it becomes large and compressive.

It’s usually an incidental finding during routine physical examination when a solid nodule or a dominant mass in the thyroid is evident. When the lump in the thyroid is large enough, it can cause compression in the neck leading to other clinical manifestations, such as the following:

• Dysphonia or other voice changes
• Difficulty breathing
• Difficulty swallowing
• Sore throat or neck pain

Difficulty swallowing and breathing occurs because the mass compresses the digestive tract (esophagus) and trachea. On the other hand, other possible complications of Hürthle cell cancer may include the spread of cancer cells to other tissues or organs, worsening the prognosis.

Associated risk factors

Risk factors associated with Hürthle cell cancer are:

• Old age
• Being female
• A family history of thyroid cancer
• Previous radiation treatments to the head or neck

Diagnosis of Hürthle cell cancer

Thyroid oncocytoma is usually an incidental finding in the presence of an enlarged thyroid gland or a single nodule during a physical examination carried out for any reason. In addition to identifying the presence of this anomaly, its size and shape should be analyzed, as well as the surrounding lymph nodes for inflammation and/or lymphatic spread.

On the other hand, when Hürthle cell cancer causes voice changes or any symptoms indicating vocal cord involvement, the vocal cords should be examined by laryngoscopy.

However, the definitive diagnosis is made by a histologic study by biopsy, in which a sample of thyroid tissue is extracted for analysis. This is taken with a fine needle that’s passed through the skin of the neck guided by ultrasound images.

Treatment

Initially, the treatment of Hürthle cell cancer is surgical. Surgery is performed to remove the thyroid, with total or near-total removal (total or subtotal thyroidectomy).

In the case of suspicion of dissemination to the surrounding lymph nodes, it will be necessary to remove them. After thyroidectomy, the physiological production of thyroid hormones is suppressed, so they must be supplemented daily for life. Levothyroxine is one of the key hormones for proper metabolic function.

In addition, there are risks associated with thyroidectomy:

• Incidental injury to the nerve that controls the larynx (recurrent laryngeal nerve) resulting in temporary or permanent dysphonia and even loss of voice.
• Excessive bleeding at the incision site.
• Involvement of the parathyroid gland which is located posterior to the thyroid gland and regulates calcium levels in the blood. If suspected, as with levothyroxine, it should be administered daily for life.

Following surgery, radioactive iodine therapy is usually recommended to destroy any remaining thyroid tissue that may contain traces of cancer cells. It not only helps destroy the remaining tissue, but also cells that spread to other parts of the body.

The treatment consists of a pill with radioactive iodine and has temporary adverse effects, such as a dry mouth, slight loss of taste, neck tenderness, nausea, and tiredness.

If the above treatment didn’t work, radiation therapy with high-powered energy beams such as X-rays or protons would be used to destroy the cancer cells. This is usually the ideal alternative in cases of metastasis.

Enlargement of the thyroid gland requires medical evaluation

Hürthle cell cancer, as well as other types of thyroid cancer, may be asymptomatic and show no symptoms. Therefore, when doctors find an enlarged thyroid gland or the presence of a single nodule, then this should require a histologic study of the tissue to determine if cancer cells are present.