Follicular thyroid carcinoma

Follicular Thyroid Carcinoma

Follicular thyroid carcinoma (FTC) is a type of thyroid cancer that arises from the follicular cells of the thyroid gland. It is the second most common type of thyroid cancer, following papillary thyroid carcinoma. FTC is known for its potential to metastasize through the bloodstream, often affecting the lungs and bones.

Pathophysiology

Follicular thyroid carcinoma originates from the follicular cells, which are responsible for the production and secretion of thyroid hormones. Unlike papillary thyroid carcinoma, FTC is characterized by the absence of papillary structures and the presence of capsular and vascular invasion. The diagnosis of FTC is often confirmed through histological examination, where the invasion of blood vessels or the capsule is observed.

Epidemiology

FTC accounts for approximately 10-15% of all thyroid cancers. It is more prevalent in regions with iodine deficiency, as iodine is essential for thyroid hormone synthesis. The incidence of FTC is higher in females compared to males, and it typically presents in individuals over the age of 40.

Clinical Presentation

Patients with follicular thyroid carcinoma may present with a solitary thyroid nodule, which is often painless. In some cases, the nodule may be associated with symptoms of compression, such as difficulty swallowing or breathing, if it grows large enough. Unlike papillary thyroid carcinoma, FTC is less likely to present with lymph node involvement.

Diagnosis

The diagnosis of FTC is challenging due to its similarity to benign follicular adenomas. Fine-needle aspiration (FNA) biopsy is commonly used, but it cannot reliably distinguish between benign and malignant follicular lesions. Therefore, a surgical excision and histopathological examination are often required to confirm the diagnosis.

Treatment

The primary treatment for follicular thyroid carcinoma is surgical removal of the thyroid gland, known as a thyroidectomy. Depending on the extent of the disease, a total or partial thyroidectomy may be performed. Radioactive iodine therapy is often used postoperatively to ablate any remaining thyroid tissue and to treat metastatic disease. Long-term follow-up with serum thyroglobulin levels and imaging studies is essential to monitor for recurrence.

Prognosis

The prognosis for patients with follicular thyroid carcinoma is generally favorable, especially when the disease is detected early and treated appropriately. The 10-year survival rate is high, but it decreases in cases with distant metastasis or poorly differentiated tumors.

Also see

• Thyroid cancer
• Papillary thyroid carcinoma
• Medullary thyroid carcinoma
• Anaplastic thyroid carcinoma
• Thyroidectomy