Thyroid cancer

Thyroid Cancer Main Page
Patient Information
Overview
Classification Papillary Thyroid Cancer Follicular Thyroid Cancer Medullary Thyroid Cancer Anaplastic Thyroid Cancer Thyroid Lymphoma
Causes
Differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Michael Maddaleni, B.S.; Ammu Susheela, M.D. [2],Seyedmahdi Pahlavani, M.D. [3], Sahar Memar Montazerin, M.D.[4]

Overview

Thyroid cancer refers to any of four kinds of tumors of the thyroid gland which include papillary, follicular, medullary and anaplastic tumors. Papillary and follicular tumors are the most common and are usually benign. Papillary and follicular tumors have a slow growth and may recur, but are generally not fatal in patients under 45 years of age. Medullary and anaplastic tumors are malignant. Medullary tumors have a good prognosis if the are restricted to the thyroid gland and a poorer prognosis if metastasis occurs. Anaplastic tumors are fast-growing and respond poorly to therapy. Thyroid nodules are diagnosed by ultrasound guided fine needle aspiration or frequently by thyroidectomy (surgical removal and subsequent histological examination). As the thyroid cancer can uptake iodine, radioactive iodine is commonly used for the treatment of thyroid carcinomas. However, radioactive iodine therapy is accompanied by thyroxine therapy to ensure TSH suppression.

Classification

Thyroid cancers can be classified according to their pathological characteristics. The following variants can be distinguished (distribution over various subtypes may show regional variation):

• Papillary thyroid cancer (75%, including mixed papillary/follicular)
• Follicular thyroid cancer (16%)
• Medullary thyroid cancer (5-7%)
• Anaplastic thyroid cancer (3%)
• Lymphoma (1%)

Thyroid carcinoma                                                                                                                                                                                         Papillary thyroid cancer   Follicular thyroid cancer   Medullary thyroid cancer           Anaplastic thyroid cancer   Lymphoma   Miscellaneous                                                                                                                       •Follicular variant •Tall cell •Diffuse sclerosing •Encapsulated •Columnar   •Minimally invasive •Overtly invasive                   •Small cell •Giant cell           •Sarcoma •Lymphoma •Squamous cell carcinoma •Mucoepidermoid carcinoma •Plasma cell tumors •Direct extension •Kidney •Melanoma •Colon

Differential diagnosis

Thyroid cancers should be differentiated from one another and from various other diseases:

Disease name	Age of onset	Gender preponderance	Signs/Symptoms	Imaging Feature(s)	Macroscopic feature(s)	Microscopic feature(s)	Laboratory Feature(s)	Other Feature(s)	Microscopic appearance
Papillary Thyroid Cancer	More common in the middle aged (30 - 50 years of age)	More commonly affects women	Asymptomatic thyroid mass or nodule Compressive symptoms, such as: Difficulty swallowing/breathing Persistent cough Stridor Vocal chord paralysis Rapid enlarging mass	On ultrasound Solitary mass with an irregular outline Located in the sub-capsular region High vascularity Imaging features are not characteristic for this cancer	Solitary hypoechogenic nodule with lobulated margin which may extend into adjacent tissues Calcification may be present or not	Empty-appearing nuclei with central clearing (Orphan Annie eye) Psammoma bodies	Thyroid function tests can be normal Thyroglobulin can be used as a tumor marker	History of radiation to the head and neck BRAF and/or RET mutation may be present The most common type of thyroid cancer	Source:Wikimedia commons
Follicular Thyroid Cancer	Peak incidence is 40-60 years of age	More commonly affects women	Asymptomatic thyroid mass or nodule Compressive symptoms such as: Difficulty swallowing/breathing Persistent cough Stridor Vocal chord paralysis Rapid enlarging mass	Ultrasound: solid hypoechoic nodule with a peripheral halo indicating fibrous capsule Irregular margin Imaging features are not characteristic for this cancer	Single encapsulated nodule, Thick and irregular capsule May have cystic or hemorrhage	Invades thyroid capsule and vasculature Uniform follicles	Thyroid function test may be normal Serum thyroglobulin may be used as a tumor marker	RAS mutation may be present PAX8-PPAR-γ translocations	Source:Wikimedia common
Medullary Thyroid Cancer	Incidence increases with age More common in 3rd to 4th decades of life	Both genders affected equally	Solitary thyroid nodule Mostly affects upper lobe of thyroid gland Possible systemic symptoms due to hormonal secretion by the tumor Cervical lymphadenopathy	Ultrasound: solitary hypoechoic nodule with or without calcification Imaging features are not characteristic for this cancer	Single nonencapsulated mass Gray-tan color	Sheets of cells in an amyloid stroma	Secretes calcitonin Normal thyroid function test Carcinoembryonic antigen (CEA) may be used as a tumor marker Rarely negative for calcitonin	May be part of MEN 2A and 2B syndrome May be associated with RET mutation	Source:Wikimedia common
Anaplastic Thyroid Cancer	More common among older individuals Mean age at diagnosis is 65 years	More commonly affects women	Rapidly enlarging thyroid mass May manifest with compressive symptoms May present with signs/symptoms of metastasis Constitutional symptoms may be present Hard nodular goiter w/out tenderness	Ultrasound: solid hypoechoic nodule with a peripheral halo indicating fibrous capsule Irregular margin Imaging features are not characteristic for this cancer	Solid tumor with areas of necrosis and hemorrhage Infiltrative pattern	Undifferentiated, devastatingly aggressive variant of Papillary/Follicular thyroid cancer	Normal thyroid function test	Poor prognosis May be associated with TP53 mutation	Source:Wikimedia common
Follicular Adenoma	More commonly affects individuals older than 50 years of age	More commonly affects women	Asymptomatic or symptoms of hyperthyroidism	Solitary nodule which may show echogenicity or not	Solitary, spherical, and encapsulated lesion Well demarcated from the surrounding parenchyma	Uniform follicles Absence of capsular or vascular invasion	Functional adenoma: Elevated T3, T4 Decreased TSH	May be considered functional or hot May be considered non-functional or cold	Source:Wikimedia common
Multinodular Goiter	Commonly affects individuals older than 60 years of age	More commonly affects women	Thyroid enlargement Signs/symptoms of hypo/hyperthyroidism	Multiple nodules with different echogenicity Calcification may be present	Multiple thyroid nodules	Variable sized follicles Some may show papillary projections without nuclear characteristics of papillary thyroid cancer	Classified as toxic and non-toxic Toxic => hyperthyroidism Non-toxic => Normal thyroid function test	Benign condition	Source:pathology outline, case courtesy of Dr. Swati Satturwar
Thyroid Lymphoma	Affects adults or elderly	More common among women	Rapidly enlarging mass/ nodule of thyroid Compression symptoms may be present Constitiutional symptoms may be present in 10% P/E:Firm, hard thyroid Fixed to the nearby structure Immobile even during swallowing Cervical or supraclavicular lymphadenopathy may be present	Ultrasound: hypoechogenic appearance difficult to be distinguished from chronic thyroiditis	Thyroid nodule/mass fixing to adjacent tissue with a firm texture	It is of B cell lineage in the majority of cases Dffuse, large B-cell lymphomas is the most common subtype: diffuse infiltrate of B cells destroying thyroid follicles Marginal zone lymphoma is the second most common type	No specific test Some may have hypothyroidism Some may have antibody against thyroid peroxidase or thyroglobulin	Preexisting chronic autoimmune (Hashimoto's) thyroiditis is a known risk factor for this condition	Source:pathology outline, case courtesy of Dr. Mark R. Wick