Hurthle cells

Hurthle cells, also known as oxyphil cells, are a type of cell found in the thyroid gland. They are characterized by their distinct large size, abundant granular cytoplasm, and prominent nucleoli. These cells are named after the German pathologist Karl Hurthle, who first described them in 1894. Hurthle cells are of particular interest in medical diagnostics as their presence in thyroid tissue can be indicative of certain types of thyroid disease, including Hurthle cell adenoma and Hurthle cell carcinoma.

Characteristics

Hurthle cells are derived from follicular cells in the thyroid gland. They undergo a transformation that leads to their unique appearance, which includes a deeply eosinophilic, granular cytoplasm due to the high number of mitochondria. This transformation can occur in response to various stimuli, including chronic thyroiditis, particularly Hashimoto's thyroiditis, and in response to aging. Despite their alarming appearance under the microscope, the presence of Hurthle cells is not always indicative of malignancy.

Clinical Significance

The clinical significance of Hurthle cells lies in their association with certain thyroid conditions. Hurthle cell adenomas are benign tumors that consist predominantly of Hurthle cells, whereas Hurthle cell carcinomas are malignant tumors with similar histology but with evidence of invasion or metastasis. The distinction between benign and malignant Hurthle cell tumors can be challenging and often requires a surgical biopsy for definitive diagnosis.

Hurthle Cell Adenoma

Hurthle cell adenoma is a benign tumor that can cause local symptoms due to its size, such as difficulty swallowing or breathing and a noticeable lump in the neck. These tumors are usually solitary and encapsulated, with a low risk of progression to malignancy.

Hurthle Cell Carcinoma

Hurthle cell carcinoma, on the other hand, is a rare form of thyroid cancer that tends to occur in older patients. It can be more aggressive than other thyroid cancers, with a higher risk of metastasis, particularly to the lungs and bones. Treatment typically involves surgical removal of the thyroid gland, possibly followed by radioactive iodine therapy.

Diagnosis

The diagnosis of Hurthle cell-related conditions often involves a combination of thyroid function tests, imaging studies such as ultrasound, and fine-needle aspiration (FNA) biopsy. The presence of Hurthle cells in a biopsy sample can raise suspicion for a Hurthle cell tumor, but further testing is usually required to determine the nature of the lesion.

Treatment

Treatment for Hurthle cell tumors depends on whether the tumor is benign or malignant. Surgery is the mainstay of treatment for both conditions, with the extent of surgery depending on the size of the tumor, its characteristics, and whether there is evidence of spread. Radioactive iodine therapy may be considered for malignant cases to target residual thyroid tissue or metastatic disease.

Prognosis

The prognosis for individuals with Hurthle cell adenoma is generally excellent, with surgical removal often being curative. The prognosis for Hurthle cell carcinoma, while generally good, depends on factors such as the stage of the disease at diagnosis, the patient's age, and the presence of metastasis.