Terminology
Abbreviations
Thyroid Papillary carcinoma (TPC)
Papillary thyroid carcinoma (PTC)
Follicular variant, Thyroid Papillary carcinoma (FV-TPC)
Definition
Malignant epithelial tumors of follicular cell origin that present as differentiated and characteristic nuclear changes.
Etiology/Pathogenesis
Environmental exposure
Radioactive iodine exposure
History of childhood exposure is specifically associated with thyroid cancer
especially in “solid” TPC
Iodine-rich diet
High tumor incidence in areas with high iodine intake diets
Pre-existing benign thyroid disease
6-fold increased risk for those with nodules
28-fold increased risk of solid nodules
Genetic characteristics
5-10 times higher risk with papillary cancer in first-degree relatives such as parents
Greater than 5% of papillary cancers are familial
Familial adenomatous polyposis (FAP): germ cell mutations in the APC gene
Carney complex (mucinous tumor syndrome)
Pathogenesis
Monoclonal origin, often multicentric disease
Clinical features
Epidemiology
Morbidity monoclonal origin, often multicentric disease
Majority (85%) of all malignant thyroid tumors
Population incidence 7.9 per 100,000
Age
Common in young to middle-aged adults
Female: 20-40 years
Males: 40-60 years
Although thyroid malignancies in children are uncommon, papillary carcinoma is the most common type of pathology among them
Gender.
Female>>male (4:1)
Ethnicity.
White>>Black
Description
Solid painless thyroid mass
About 30% have coexisting cervical lymph node disease (metastatic disease)
Dysphagia, wheezing, cough: most often seen in patients with large tumors (compression symptoms)
”Episodic” tumors are often discovered unintentionally during the course of other unrelated diseases
Laboratory tests
Generally normal thyroid function
Rarely, high or low thyroid function may be present
Serum thyroglobulin is often used as an indicator of disease status (if it is elevated)
Natural course of disease
20% of TPC diagnosed by biopsy present as inert and non-invasive tumors
Treatment
Treatment strategies, risks and complications
Recurrent laryngeal nerve injury and parathyroid hypofunction are the most common complications
Surgical approach
Although the extent of surgery (lobectomy, subtotal resection or total thyroidectomy) remains controversial, surgery is the treatment of choice
Cervical lymph node dissection is recommended if lymph node enlargement is clinically or radiologically supported
Radiotherapy
Radioactive iodine therapy can be given after total thyroidectomy
The ability of the tumor to take up radioactive iodine is a prerequisite for treatment sensitivity.
Prognosis
Long-term clinical prognosis is good
20-year survival rate >98%
Mortality rate less than 0.2%
Spread through the lymphatic tract
Intraglandular spread or metastasis to regional lymph nodes
Age (<45 years), size, and sex (female) are the most important prognostic factors
Significantly more patients older than 45 years present with extrathyroidal spread and metastasis
RET/PTC3 positive papillary carcinomas (typical solid tumors) have a slightly worse prognosis