Hürthle cell adenoma is a rare form of thyroid cancer that disproportionately affects women. Like all adenomas, Hürthle cell adenomas are benign, but they have the potential to become carcinomas, which are malignant.
Hürthle cell adenoma was first identified by Dr. James Ewing in 1928 (the cells themselves were discovered by Karl Hürthle in 1894), and most cases occur in patients between seventy and eighty years old. Even large clusters of Hürthle cells may not be life threatening, but Hürthle cell adenomas have the potential to become malignant and metastasize to other bodily organs.
Symptoms and Risk Factors
Hürthle cell adenomas and carcinomas have a higher incidence in people who have other, non-malignant thyroid problems like Graves disease, colloid nodular disease, lymphocytic thyroiditis, thyroid hyperplasia, parathyroid adenoma, and follicular adenomas. Patients who have experienced excessive irradiation of the head and neck are also at increased risk, especially for malignancy.
The most common clinical sign of a Hürthle cell adenoma is a palpable mass in the thyroid, although this may only be noted by a doctor. Patients may feel pain or pressure in the affected area, and those with malignant conditions (Hürthle cell carcinoma) may experience difficulty swallowing, shortness of breath, coughing, choking spells, or hoarseness. Some patients with Hürthle cell adenomas also suffer from hypothyroidism (under active thyroid gland).
The first step in diagnosing a Hürthle cell adenoma is to establish the existence of a thyroid tumor. Second, a physician must determine whether the tumor is malignant or benign. Preliminary data about the location and size of the tumor is usually gleaned through imaging technology such as CT scans, MRI scans, or ultrasounds. Tests of thyroid function are also helpful.
After a tumor is detected, the next step in attaining a proper diagnosis requires the extraction of tissues from the tumor to be examined in a laboratory under a microscope. This tissue extraction may involve the minimally invasive fine needle aspiration biopsy technique, whereby a needle is inserted into the tumor to collect cancer cells for study.
Regardless of whether or not the tumor is malignant, Hürthle cell adenomas and carcinomas are both removed promptly to prevent the disease from progressing further. However, if the tumor is malignant, doctors tend to remove all thyroid tissue, whereas they only remove the affected lobe (half of the thyroid) when a Hürthle cell adenoma is present.
Hürthle cells are resistant to radiation treatment, so it is difficult to treat recurrences, although doctors have found some success with using radioactive iodine treatment to slow the progress of the disease.