Papillary thyroid carcinoma
Papillary thyroid carcinoma is the most common thyroid malignancy, arising from thyroid follicular cells and typically spreading to cervical lymph nodes with a low risk of distant metastasis. Diagnosis rests on ultrasound risk stratification and fine-needle aspiration biopsy, and treatment is thyroid lobectomy or total thyroidectomy, with postoperative radioactive iodine and thyroid-stimulating-hormone-suppressive levothyroxine reserved for intermediate to high risk disease.
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What this article covers
- Overview
The most common thyroid malignancy: papillary thyroid carcinoma (PTC) accounts for roughly 80% to 90% of thyroid cancers and arises from thyroid hormone-producing follicular cells.
- Epidemiology
Thyroid cancer incidence has risen over recent decades: much of this increase reflects incidental detection of small, noninvasive cancers on imaging obtained for other reasons (carotid Doppler…
- Risk factors
Prior ionizing radiation exposure: the principal identified environmental risk factor, with the highest risk in patients exposed during childhood, such as from treatment of childhood cancer or nuclear accidents.
- Pathophysiology
Malignant transformation of thyroid follicular cells: both papillary and follicular thyroid carcinoma arise from the thyroid hormone-producing follicular cells, distinguishing them from medullary…
- Clinical features
A thyroid nodule, palpable or incidentally discovered: the most common presentation, often found on physical examination or incidentally on imaging performed for another reason.
- Differential diagnosis
Follicular thyroid carcinoma: also arises from follicular cells and can present as a thyroid nodule, but spreads hematogenously to lung, bone, and other distant sites rather than to cervical lymph…
- Diagnosis
The diagnosis is established, first, by measuring serum thyroid-stimulating hormone (TSH) as the initial laboratory step in evaluating any thyroid nodule, then confirmed by fine-needle aspiration…
- Management
First, perform surgery, the mainstay of treatment: thyroid lobectomy or total thyroidectomy for unilateral differentiated thyroid cancers with nodules 1 to 4 cm without suspected locoregional spread…
- Complications
Hypocalcemia from parathyroid injury or removal: a recognized risk of thyroid surgery requiring calcium and vitamin D monitoring and replacement.
- Prognosis
Excellent overall survival: the overall 5-year survival for thyroid cancer is 98.1%, and mortality rates have remained stable despite rising incidence, reflecting increased detection of small, indolent tumors.
- Prevention
No specific primary prevention exists for sporadic papillary thyroid carcinoma, since it arises from acquired molecular alterations (RET/PTC rearrangements, BRAF mutations) rather than a modifiable exposure in most patients.
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Related articles
- Follicular thyroid carcinoma
Follicular thyroid carcinoma is the second most common differentiated thyroid cancer, accounting for 10% to 15% of thyroid cancer cases, and characteristically spreads hematogenously to lung, bone, and brain rather than to cervical lymph nodes. Because fine-needle aspiration cytology cannot reliably distinguish it from a benign follicular adenoma, diagnosis often requires diagnostic lobectomy, and treatment is surgery followed by postoperative radioactive iodine and thyroid-stimulating-hormone-suppressive levothyroxine for higher-risk disease.
- Medullary thyroid carcinoma
Medullary thyroid carcinoma is a neuroendocrine tumor of the parafollicular C cells that secretes calcitonin and is familial (RET-mutant, part of MEN2A or MEN2B) in about 25% of cases. First-line treatment is total thyroidectomy with central neck lymph node dissection, with any coexisting pheochromocytoma resected first, followed by lifelong levothyroxine replacement and calcitonin/CEA surveillance; selpercatinib, a RET kinase inhibitor, is used for unresectable or metastatic RET-mutant disease.
- Anaplastic thyroid carcinoma
Anaplastic thyroid carcinoma is a rare, highly aggressive, undifferentiated thyroid malignancy that presents as a rapidly enlarging neck mass, arising de novo or from a preexisting differentiated thyroid cancer, and is often unresectable at diagnosis with a median survival of about 5 months. Treatment is largely palliative multimodality therapy with surgery when feasible, external beam radiation therapy, and chemotherapy, since the disease has typically outpaced the possibility of cure by the time it is recognized.
- Thyroid nodules
A thyroid nodule is a discrete structural lesion within an otherwise normal thyroid gland, found on ultrasound in about 40% of the United States population though palpable in far fewer, and malignant in roughly 5%. Evaluation begins with a thyroid-stimulating hormone (TSH) level and thyroid ultrasonography, and management is surveillance for benign or low-risk nodules, with lobectomy or total thyroidectomy reserved for cytology suspicious for or diagnostic of malignancy.