{"id":4422366,"date":"2025-01-11T15:18:20","date_gmt":"2025-01-11T21:18:20","guid":{"rendered":"https:\/\/myendoconsult.com\/learn\/topics\/thyroid-carcinomas\/"},"modified":"2025-01-13T05:56:57","modified_gmt":"2025-01-13T11:56:57","slug":"thyroid-carcinomas","status":"publish","type":"oen_topic","link":"https:\/\/myendoconsult.com\/learn\/topics\/thyroid-carcinomas\/","title":{"rendered":"Thyroid Carcinomas"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">PAPILLARY THYROID CARCINOMA (PTC)<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Definition and Prevalence<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Papillary Thyroid Carcinoma (PTC)<\/strong>: One of three thyroid epithelial\u2013derived carcinomas (the others are follicular and anaplastic).<\/li>\n\n\n\n<li><strong>Most common malignant thyroid tumor<\/strong>: ~75% of thyroid cancer cases.<\/li>\n\n\n\n<li><strong>Peak Incidence<\/strong>: 4th and 5th decades of life (i.e., ages 30s to 50s).<\/li>\n\n\n\n<li><strong>Gender Predominance<\/strong>: ~2.5:1 ratio in women vs. men.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Clinical Presentation<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong><a href=\"https:\/\/myendoconsult.com\/learn\/evaluation-of-a-thyroid-nodule-an-algorithm-based-approach\/\" data-wpil-monitor-id=\"135\">Thyroid Nodule<\/a><\/strong>\n<ul class=\"wp-block-list\">\n<li>Often presents as a <strong>solitary <a href=\"https:\/\/myendoconsult.com\/learn\/topics\/toxic-thyroid-nodules\/\" data-wpil-monitor-id=\"136\">thyroid nodule<\/a><\/strong>.<\/li>\n\n\n\n<li>Increasingly detected incidentally on imaging (CT, ultrasound) done for other reasons.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Multifocality<\/strong>\n<ul class=\"wp-block-list\">\n<li>PTC frequently has multiple foci within the thyroid.<\/li>\n\n\n\n<li>When presenting via cervical lymph node biopsy showing \u201cpapillary lesion,\u201d at least half of the intrathyroidal foci may be <strong>genetically distinct<\/strong> (independent clones).<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Histopathology<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Gross and Microscopic Features<\/strong>\n<ul class=\"wp-block-list\">\n<li>Typically <strong>unencapsulated<\/strong>.<\/li>\n\n\n\n<li>Characterized by <strong>papillary cords<\/strong> with delicate vascularized stroma lined by cuboidal\/columnar cells.<\/li>\n\n\n\n<li><strong>Pure PTC<\/strong> usually lacks colloid\/follicles.<\/li>\n\n\n\n<li><strong>Nuclear Features<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Large, oval nuclei with <strong>hypodense (Orphan Annie\u2013eye) chromatin<\/strong>.<\/li>\n\n\n\n<li>Cytoplasmic \u201cpseudoinclusions\u201d (redundant nuclear membrane).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Psammoma Bodies<\/strong>: Found in ~50% of PTC (calcified, scarred remains of tumor papillae).<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1072\" height=\"670\" src=\"https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/PTC-showing-classic-features.jpg\" alt=\"\" class=\"wp-image-4416321\" srcset=\"https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/PTC-showing-classic-features.jpg 1072w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/PTC-showing-classic-features-300x188.jpg 300w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/PTC-showing-classic-features-768x480.jpg 768w\" sizes=\"auto, (max-width: 1072px) 100vw, 1072px\" \/><figcaption class=\"wp-element-caption\">Papillary thyroid carcinoma, classic nuclear features\nMarked nuclear enlargement (compare to normal thyroid follicular epithelium)\nNuclear crowding\nGrooves (short arrow)\nNuclear condensation to the periphery of the nucleus (Orphan Annie Eye)\nPapillary architecture characterized by fibrovascular core (long arrow)\n<\/figcaption><\/figure>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Variants<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Follicular Variant<\/strong> (~10%): Follicles plus classic PTC nuclear changes; overall prognosis similar to classic PTC.<\/li>\n\n\n\n<li><strong>Tall-Cell Variant<\/strong> (~1%): More aggressive; larger, more invasive.<\/li>\n\n\n\n<li><strong>Other Rare Variants<\/strong> (e.g., clear-cell, insular, columnar, trabecular, oxyphilic, diffuse sclerosing) \u2192 often more aggressive behavior.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Metastatic Patterns<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Regional Lymph Nodes<\/strong> (cervical, upper mediastinal) frequently involved.<\/li>\n\n\n\n<li><strong>Distant Metastases<\/strong> are uncommon at initial diagnosis (~2%):\n<ul class=\"wp-block-list\">\n<li><strong>Lung<\/strong> is the most frequent distant site (often showing miliary pattern on imaging).<\/li>\n\n\n\n<li><strong>Bone<\/strong> less common (more likely in older patients).<\/li>\n\n\n\n<li>Rare sites: Brain, liver, kidney, adrenal glands.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"3000\" height=\"2100\" src=\"https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/Thyroid-Cancer-Staging-Infographic.png\" alt=\"\" class=\"wp-image-4422834\" srcset=\"https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/Thyroid-Cancer-Staging-Infographic.png 3000w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/Thyroid-Cancer-Staging-Infographic-300x210.png 300w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/Thyroid-Cancer-Staging-Infographic-768x538.png 768w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/Thyroid-Cancer-Staging-Infographic-1536x1075.png 1536w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/Thyroid-Cancer-Staging-Infographic-2048x1434.png 2048w\" sizes=\"auto, (max-width: 3000px) 100vw, 3000px\" \/><figcaption class=\"wp-element-caption\">Staging of Thyroid Carcinoma<\/figcaption><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Prognosis and Risk Factors<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Overall Behavior<\/strong>\n<ul class=\"wp-block-list\">\n<li>One of the <strong>least aggressive<\/strong> human cancers; many patients do not die of PTC.<\/li>\n\n\n\n<li>Still can be fatal in some cases, especially if high-risk features present.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>High-Risk Features for Recurrence\/Mortality<\/strong>\n<ul class=\"wp-block-list\">\n<li>Age &gt;45 years at diagnosis.<\/li>\n\n\n\n<li>Tumor size &gt;7 cm.<\/li>\n\n\n\n<li>Soft-tissue invasion (e.g., trachea, esophagus).<\/li>\n\n\n\n<li>Additional risk factors: Male gender, multicentric PTC, &gt;10 lymph node metastases, age &lt;7 years.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Treatment<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Surgical Management<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Total Thyroidectomy + Central Compartment Lymphadenectomy<\/strong> for PTC &gt;1 cm or with known nodal metastases.<\/li>\n\n\n\n<li>More extensive surgery if there is extrathyroidal invasion (trachea, esophagus).<\/li>\n\n\n\n<li><strong>Less Extensive Resection<\/strong> (lobectomy + isthmusectomy) may suffice for solitary PTC &lt;1 cm.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><a href=\"https:\/\/myendoconsult.com\/learn\/radioactive-iodine-uptake-and-scan\/\" data-wpil-monitor-id=\"142\">Radioactive Iodine<\/a> (131I)<\/strong>\n<ul class=\"wp-block-list\">\n<li>Adjuvant therapy to ablate residual microscopic disease.<\/li>\n\n\n\n<li>Not universally used; patient selection is individualized.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>External-Beam Radiotherapy<\/strong>\n<ul class=\"wp-block-list\">\n<li>Considered in unresectable disease not responsive to 131I.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Chemotherapy \/ Targeted Therapy<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Systemic chemotherapy<\/strong> for aggressive, symptomatic, refractory disease.<\/li>\n\n\n\n<li><strong>Tyrosine Kinase Inhibitors<\/strong> and other molecular pathway\u2013blocking drugs under investigation for refractory cases.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><a href=\"https:\/\/myendoconsult.com\/learn\/thyroid-hormone-synthesis\/\" data-wpil-monitor-id=\"143\">Thyroid Hormone<\/a> Suppression<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Levothyroxine<\/strong> therapy postoperatively to suppress TSH and reduce tumor stimulation.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">FOLLICULAR THYROID CARCINOMA (FTC)<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Definition and Incidence<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>One of three<\/strong> thyroid epithelial\u2013derived cancers (others: papillary carcinoma, anaplastic carcinoma).<\/li>\n\n\n\n<li><strong>Second most common<\/strong> thyroid cancer after papillary thyroid carcinoma (PTC), accounting for <strong>\u223c10%<\/strong> of all thyroid malignancies.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Demographics and Risk Factors<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Peak Incidence<\/strong>: 40\u201360 years of age.<\/li>\n\n\n\n<li><strong>Female : Male ratio<\/strong> ~3:1.<\/li>\n\n\n\n<li><strong>Geographic <a href=\"https:\/\/myendoconsult.com\/learn\/cretinism-an-iodine-deficiency-disorder\/\" data-wpil-monitor-id=\"144\">Iodine Deficiency<\/a><\/strong>: More common in iodine-deficient regions.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Clinical Presentation<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Thyroid Nodule or Mass<\/strong>\n<ul class=\"wp-block-list\">\n<li>May be small or large.<\/li>\n\n\n\n<li>Typically <strong>solitary<\/strong> intrathyroidal focus (unlike PTC, which can be multifocal).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Fine-Needle Aspiration (FNA) Limitations<\/strong>\n<ul class=\"wp-block-list\">\n<li>Cytology cannot distinguish FTC from a <strong>benign follicular adenoma<\/strong>.<\/li>\n\n\n\n<li>Definitive diagnosis requires <strong>histologic<\/strong> evidence of <strong>tumor capsule or vascular invasion<\/strong> from en bloc surgical specimen.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Histopathology<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Follicular Pattern<\/strong>\n<ul class=\"wp-block-list\">\n<li>Organized follicles lined by high cuboidal epithelium, often containing colloid.<\/li>\n\n\n\n<li><strong>No papillary features<\/strong> (e.g., no psammoma bodies).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Capsular or Vascular Invasion<\/strong>\n<ul class=\"wp-block-list\">\n<li>Hallmark for malignancy (distinguishes from benign adenoma).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Subtypes<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Minimally Invasive FTC<\/strong>: Encapsulated, better prognosis.<\/li>\n\n\n\n<li><strong>Widely Invasive FTC<\/strong>: Invades blood vessels and adjacent thyroid tissue; worse prognosis.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Molecular Genetics<\/strong>\n<ul class=\"wp-block-list\">\n<li>Often <strong>monoclonal<\/strong>; ~40% have <strong>RAS<\/strong> point mutations, associated with more aggressive behavior.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Metastasis and Spread<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Hematogenous Dissemination<\/strong>: Common; distant metastases in ~15% of patients at diagnosis.<\/li>\n\n\n\n<li><strong>Most Frequent Sites<\/strong>: Bone, lung (less commonly liver, brain, urinary bladder, skin).<\/li>\n\n\n\n<li><strong>Lymph Node Metastases<\/strong>: Much less common than in PTC.<\/li>\n\n\n\n<li><strong>Skeletal Metastases<\/strong>: May histologically resemble <a href=\"https:\/\/myendoconsult.com\/learn\/normal-thyroid-ultrasound-images\/\" data-wpil-monitor-id=\"137\">normal thyroid<\/a> tissue.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Prognosis<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Generally More Aggressive<\/strong> than papillary carcinoma.<\/li>\n\n\n\n<li>Poor prognosis factors:\n<ol class=\"wp-block-list\">\n<li><strong>Larger Tumors<\/strong><\/li>\n\n\n\n<li><strong>Distant Metastasis<\/strong><\/li>\n\n\n\n<li><strong>Vascular Invasion<\/strong><\/li>\n<\/ol>\n<\/li>\n\n\n\n<li><strong>Insular Carcinoma<\/strong>: A poorly differentiated FTC variant with a poor prognosis.<\/li>\n\n\n\n<li><strong><a data-wpil-monitor-id=\"138\" href=\"https:\/\/myendoconsult.com\/learn\/histology-of-hurthle-cell-adenoma-and-carcinoma\/\">H\u00fcrthle Cell Carcinoma<\/a><\/strong>: Oncocytic variant of FTC.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1583\" height=\"985\" src=\"https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/Hurthle-cell-carcinoma.jpg\" alt=\"Hurthle cell carcinoma with a focus of vascular invasion into a thick capsule\" class=\"wp-image-4416310\" srcset=\"https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/Hurthle-cell-carcinoma.jpg 1583w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/Hurthle-cell-carcinoma-300x187.jpg 300w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/Hurthle-cell-carcinoma-768x478.jpg 768w, https:\/\/myendoconsult.com\/learn\/wp-content\/uploads\/Hurthle-cell-carcinoma-1536x956.jpg 1536w\" sizes=\"auto, (max-width: 1583px) 100vw, 1583px\" \/><figcaption class=\"wp-element-caption\">Hurthle cell carcinoma with a focus of vascular invasion into a thick capsule\n<\/figcaption><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Treatment<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Surgical Management<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Total Thyroidectomy<\/strong> + <strong>Central Neck Lymph Node Dissection<\/strong> = standard of care.<\/li>\n\n\n\n<li>Preoperative <strong>neck ultrasonography<\/strong> for lymph node mapping is essential.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><a href=\"https:\/\/myendoconsult.com\/learn\/radioactive-iodine-uptake-and-scan\/\" data-wpil-monitor-id=\"145\">Radioactive Iodine<\/a> (131I)<\/strong>\n<ul class=\"wp-block-list\">\n<li>FTC cells can take up 131I but less efficiently than <a href=\"https:\/\/myendoconsult.com\/learn\/normal-thyroid-follicular-cells\/\" data-wpil-monitor-id=\"139\">normal<\/a> follicular cells.<\/li>\n\n\n\n<li>131I used post-thyroidectomy to ablate remnant thyroid and microscopic metastatic disease.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><a href=\"https:\/\/myendoconsult.com\/learn\/thyroid-hormone-synthesis\/\" data-wpil-monitor-id=\"146\">Thyroid Hormone<\/a> Suppression<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Levothyroxine<\/strong> replacement post-surgery to suppress TSH, aiming to prevent TSH-driven tumor growth.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>External-Beam Radiation Therapy<\/strong>\n<ul class=\"wp-block-list\">\n<li>Used if residual primary or metastatic disease is unresectable.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Chemotherapy and Targeted Therapy<\/strong>\n<ul class=\"wp-block-list\">\n<li>Systemic chemotherapy for disease <strong>refractory<\/strong> to other treatments.<\/li>\n\n\n\n<li><strong>Molecular pathway inhibitors<\/strong> (e.g., tyrosine kinase inhibitors) under investigation for refractory cases.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">MEDULLARY THYROID CARCINOMA (MTC)<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Definition and Incidence<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Neoplasm of Thyroid \u201cC Cells\u201d<\/strong>: Parafollicular cells derived from the embryonic neural crest.<\/li>\n\n\n\n<li><strong>Accounts for ~3%<\/strong> of all thyroid malignancies.<\/li>\n\n\n\n<li>More accurately considered a <strong>neuroendocrine tumor<\/strong> rather than a conventional thyroid carcinoma.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Sporadic vs. Familial<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Sporadic MTC<\/strong>\n<ul class=\"wp-block-list\">\n<li>~80% of cases.<\/li>\n\n\n\n<li>Typically presents as a <strong>solitary thyroid nodule<\/strong> in patients aged <strong>40\u201360 years<\/strong>; slight female preponderance.<\/li>\n\n\n\n<li>At diagnosis, &gt;50% have <strong>regional lymph node metastases<\/strong>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Familial MTC<\/strong>\n<ul class=\"wp-block-list\">\n<li>Associated with <strong>MEN 2A<\/strong>, <strong>MEN 2B<\/strong>, or <strong>Familial MTC (FMTC)<\/strong>.<\/li>\n\n\n\n<li>Inherited in an <strong>autosomal dominant<\/strong> fashion with <strong>RET proto-oncogene mutations<\/strong>.<\/li>\n\n\n\n<li><strong>Penetrance ~100%<\/strong> in <a href=\"https:\/\/myendoconsult.com\/learn\/topics\/men-2\/\"  data-wpil-monitor-id=\"341\">MEN 2<\/a> syndromes.<\/li>\n\n\n\n<li><strong>MEN 2B<\/strong> form is more aggressive; prophylactic thyroidectomy is recommended in the <strong>first year of life<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Clinical Features and Metabolism<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Calcitonin Secretion<\/strong>: Elevated serum calcitonin can cause <strong>severe diarrhea<\/strong>.<\/li>\n\n\n\n<li>May secrete other hormones (e.g., ACTH \u2192 <a href=\"https:\/\/myendoconsult.com\/learn\/cushings-syndrome\/\" data-wpil-monitor-id=\"140\">Cushing syndrome<\/a>).<\/li>\n\n\n\n<li><strong>Fine-Needle Aspiration (FNA)<\/strong> typically diagnostic in solitary thyroid nodule.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Histopathology<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Solid Trabecular Pattern<\/strong>\n<ul class=\"wp-block-list\">\n<li>Closely packed cells with variable nuclear size\/hyperchromatism.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Immunostaining<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Calcitonin<\/strong>, <strong>Galectin-3<\/strong>, <strong>Carcinoembryonic Antigen (CEA)<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Genetic Testing<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>RET Proto-Oncogene<\/strong>\n<ul class=\"wp-block-list\">\n<li>All patients with MTC should have genetic testing because ~7% of apparently sporadic cases harbor a RET mutation.<\/li>\n\n\n\n<li>Identifies at-risk family members; allows early (prophylactic) thyroidectomy to prevent metastases.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Coexisting Endocrine Disorders<\/strong>\n<ul class=\"wp-block-list\">\n<li>Rule out <strong><a href=\"https:\/\/myendoconsult.com\/learn\/topics\/primary-hyperparathyroidism\/\"  data-wpil-monitor-id=\"342\">primary hyperparathyroidism<\/a><\/strong> and <strong>pheochromocytoma<\/strong> in MEN 2 patients.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Management<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Surgical Treatment<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Total Thyroidectomy<\/strong> is the treatment of choice.<\/li>\n\n\n\n<li>Prognosis correlates with <strong>age at diagnosis<\/strong>; familial cases have better outcomes if operated on earlier.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Monitoring<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Serum Calcitonin<\/strong> postoperatively to assess for surgical cure.<\/li>\n\n\n\n<li>Persistent elevated calcitonin suggests residual or metastatic disease.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Advanced Disease<\/strong>\n<ul class=\"wp-block-list\">\n<li>Metastases may involve <strong>neck nodes<\/strong>, <strong>mediastinum<\/strong>, <strong>lungs<\/strong>, <strong>liver<\/strong>, <strong>bone<\/strong>, <strong>kidneys<\/strong>.<\/li>\n\n\n\n<li><strong>Molecular pathway\u2013blocking drugs<\/strong> (e.g., tyrosine kinase inhibitors) for unresectable or refractory disease.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">H\u00dcRTHLE CELL THYROID CARCINOMA (HCC)<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Definition and Incidence<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Variant of Follicular Thyroid Carcinoma<\/strong> (FTC), also called the <strong>oncocytic variant<\/strong> of FTC.<\/li>\n\n\n\n<li>Accounts for <strong>3%\u20134%<\/strong> of all thyroid malignancies.<\/li>\n\n\n\n<li><strong>Distinctive Oncocytes<\/strong> (H\u00fcrthle or oxyphilic cells) constitute \u226575% of the tumor.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Demographics<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Age Range<\/strong>: Peak incidence at <strong>40\u201370 years<\/strong>, median ~61 years.<\/li>\n\n\n\n<li><strong>Gender<\/strong>: Approximately <strong>2:1<\/strong> female to male ratio.<\/li>\n\n\n\n<li>Typically presents as a <strong>painless solitary thyroid nodule<\/strong>, which may vary in size.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Pathology and Histology<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Gross Appearance<\/strong>\n<ul class=\"wp-block-list\">\n<li>Often <strong>mahogany-brown<\/strong> tumor(s) on gross examination.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Microscopic Features<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Oncocytes<\/strong>: Eosinophilic, oxyphilic cells with abundant granular cytoplasm (packed with mitochondria).<\/li>\n\n\n\n<li>Cells arranged in <strong>trabecular<\/strong> or <strong>plexiform<\/strong> patterns, separated by a dense capillary network.<\/li>\n\n\n\n<li><strong>Scant or No Colloid<\/strong> present.<\/li>\n\n\n\n<li><strong>Nuclei<\/strong>: Hyperchromatic, pleomorphic, prominent eosinophilic nucleoli.<\/li>\n\n\n\n<li><strong>Carcinoma Diagnosis<\/strong> depends on <strong>capsular invasion<\/strong>, <strong>vascular invasion<\/strong>, or <strong>metastasis<\/strong>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Radioiodine Uptake<\/strong>\n<ul class=\"wp-block-list\">\n<li>&lt;10% of HCC lesions show significant <strong>radioiodine uptake<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Clinical Behavior and Metastasis<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Comparative Aggression<\/strong>\n<ul class=\"wp-block-list\">\n<li>More aggressive than standard follicular or papillary thyroid carcinoma.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Metastases<\/strong>\n<ul class=\"wp-block-list\">\n<li>~5% have distant metastases (lung or bone) at diagnosis.<\/li>\n\n\n\n<li>~25% have <strong>regional lymph node<\/strong> metastases.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Prognostic Factors<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Distant Metastases<\/strong> at presentation \u2192 strong predictor of poor outcome.<\/li>\n\n\n\n<li><strong>Older Age<\/strong>, <strong>Larger Tumor Size<\/strong>, <strong>Male Gender<\/strong>, <strong>Extrathyroidal Invasion<\/strong> \u2192 worsen prognosis.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Recurrence Rate<\/strong>\n<ul class=\"wp-block-list\">\n<li>~35% overall recurrence post-surgery.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Treatment and Management<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Surgical Approach<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Total Thyroidectomy<\/strong> + <strong>Ipsilateral Central Neck Lymph Node Dissection<\/strong> (similar to FTC).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Adjuvant Therapy<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Radioiodine<\/strong> typically <strong>not<\/strong> beneficial (low uptake).<\/li>\n\n\n\n<li><strong>External-Beam Radiotherapy<\/strong> may be considered for <strong>unresectable<\/strong> disease.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Systemic or Targeted Therapy<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Molecular pathway\u2013blocking drugs<\/strong> (e.g., tyrosine kinase inhibitors) may help in <strong>refractory<\/strong> cases.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">ANAPLASTIC THYROID CARCINOMA (ATC)<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Definition and Incidence<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Undifferentiated Thyroid Cancer<\/strong>: One of three epithelial-derived thyroid cancers (alongside papillary and follicular).<\/li>\n\n\n\n<li><strong>Rare but Highly Malignant<\/strong>: ~2% of all thyroid malignancies.<\/li>\n\n\n\n<li><strong>Demographics<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Typically occurs <strong>after age 50<\/strong> (mean ~65 years).<\/li>\n\n\n\n<li>~Two-thirds of cases occur in <strong>women<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Clinical Presentation<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Rapid Neck Mass Growth<\/strong>\n<ul class=\"wp-block-list\">\n<li>Patients often recall a <strong>precise recent onset<\/strong> and describe rapid enlargement.<\/li>\n\n\n\n<li>Usually <strong>painful\/tender<\/strong> with local pressure symptoms (dyspnea, dysphagia, hoarseness, cough).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Systemic Symptoms<\/strong>\n<ul class=\"wp-block-list\">\n<li>Weight loss, anorexia, fatigue, fever.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Physical Examination<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Large<\/strong> tumor (often &gt;5 cm), hard, frequently fixed to surrounding tissues.<\/li>\n\n\n\n<li>Overlying skin may be warm or erythematous.<\/li>\n\n\n\n<li><strong>Cervical adenopathy<\/strong> often present.<\/li>\n\n\n\n<li>Tracheal deviation, vocal cord paralysis (recurrent laryngeal nerve involvement).<\/li>\n\n\n\n<li>Possible <strong>superior vena cava syndrome<\/strong> if tumor compresses thoracic inlet.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Pathogenesis and Precursor Lesions<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Association with Differentiated Thyroid Carcinoma<\/strong>:\n<ul class=\"wp-block-list\">\n<li>~20% have a history of PTC or FTC.<\/li>\n\n\n\n<li>~50% have a history of <a href=\"https:\/\/myendoconsult.com\/learn\/topics\/goiters\/\" data-wpil-monitor-id=\"141\">goiter<\/a>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Likely \u201cDedifferentiation\u201d<\/strong> from existing neoplasm (loss of tumor suppressor or new activating mutation).<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Diagnosis<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Biopsy<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Fine-Needle Aspiration<\/strong> or surgical biopsy.<\/li>\n\n\n\n<li>Histology: Solid, <strong>highly anaplastic<\/strong> growth with spindle cells and giant cells.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Imaging<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>CT<\/strong> of neck\/chest aids in evaluating tumor extent, tracheal compression, planning therapy.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Metastasis and Local Invasion<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Local Invasion<\/strong> is rapid and lethal, infiltrating muscle, lymph nodes, trachea, esophagus, larynx, and major blood vessels.<\/li>\n\n\n\n<li><strong>Cause of Death<\/strong>: Often tracheal compression\/asphyxia.<\/li>\n\n\n\n<li><strong>Distant Spread<\/strong>: Most commonly <strong>lungs<\/strong>, also bone, skin (chest wall), liver, heart, kidneys, adrenals.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Prognosis and Treatment<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Surgery<\/strong>\n<ul class=\"wp-block-list\">\n<li>Complete resection if tumor is apparently confined to the thyroid, but <strong>recurrence<\/strong> within months is common.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Adjuvant Therapy<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>External-beam radiotherapy<\/strong> may be considered after surgery.<\/li>\n\n\n\n<li><strong>Chemotherapy<\/strong> (e.g., paclitaxel) may provide brief partial responses.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Survival<\/strong>\n<ul class=\"wp-block-list\">\n<li>Rarely exceeds <strong>12 months<\/strong> from diagnosis.<\/li>\n\n\n\n<li><strong>Essentially 100% disease-specific mortality<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>PAPILLARY THYROID CARCINOMA (PTC) Definition and Prevalence Clinical Presentation Histopathology Metastatic Patterns Prognosis and Risk Factors Treatment FOLLICULAR THYROID CARCINOMA (FTC) Definition and Incidence Demographics and Risk Factors Clinical Presentation Histopathology Metastasis and Spread Prognosis Treatment MEDULLARY THYROID CARCINOMA (MTC) Definition and Incidence Sporadic vs. Familial Clinical Features and Metabolism Histopathology Genetic Testing Management H\u00dcRTHLE [&hellip;]<\/p>\n","protected":false},"featured_media":0,"template":"","oen_topic_chapter":[683],"class_list":["post-4422366","oen_topic","type-oen_topic","status-publish","hentry","oen_topic_chapter-thyroid-gland","post-wrapper","thrv_wrapper"],"_links":{"self":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422366","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic"}],"about":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/types\/oen_topic"}],"version-history":[{"count":14,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422366\/revisions"}],"predecessor-version":[{"id":4422837,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422366\/revisions\/4422837"}],"wp:attachment":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/media?parent=4422366"}],"wp:term":[{"taxonomy":"oen_topic_chapter","embeddable":true,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic_chapter?post=4422366"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}