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PubMed This is a summary of 91 peer-reviewed journal articles Updated
Oncology

Rare Thyroid Carcinomas: A Patient's Guide

At a Glance

Rare thyroid carcinoma is an umbrella term for uncommon thyroid cancers like anaplastic (ATC), medullary (MTC), and poorly differentiated (PDTC) carcinomas. Because each type behaves differently, it is crucial to identify your exact diagnosis to determine the right targeted treatment.

If you have been told you have a “rare” thyroid cancer, it is natural to feel a sense of isolation or increased anxiety. While common thyroid cancers (like Papillary Thyroid Cancer) are highly prevalent and often very treatable, rare types make up only a small fraction of all thyroid cancer cases [1][2].

It is important to understand that “rare thyroid cancer” is not just one disease. Instead, it is an umbrella term for several distinct conditions that behave very differently from one another [1]. In 2022, the World Health Organization (WHO) updated the way these cancers are classified to help doctors provide more precise diagnoses and targeted treatments [3][4].

How to Use This Guide

Because the four main types of rare thyroid cancer are so different, you do not need to read this entire guide from start to finish. We strongly recommend that you first identify your specific diagnosis from your pathology report, and then skip directly to the section that applies to you. Reading about highly aggressive types that you do not have may cause unnecessary panic.

01

The Biology and Types of Rare Thyroid Carcinomas

Learn about the 4 types of rare thyroid carcinoma: Medullary, Oncocytic, Poorly Differentiated (PDTC), and Anaplastic (ATC). Understand your tumor's genetics.

02

Decoding Your Pathology and Molecular Testing

Learn how to read your rare thyroid cancer pathology and molecular testing reports. Understand NGS gene mutations like BRAF, and what your results mean.

03

Medullary Thyroid Carcinoma (MTC) Treatment and Management

Learn about Medullary Thyroid Carcinoma (MTC) treatment options. Understand total thyroidectomy, RET genetic testing, and selective RET inhibitors.

04

Anaplastic Thyroid Carcinoma (ATC) Urgent Action Plan

Anaplastic Thyroid Carcinoma (ATC) is a medical emergency. Learn about rapid BRAF testing, FAST protocols, targeted therapies, and protecting your airway.

05

PDTC, High-Grade, and Oncocytic (Hürthle Cell) Guide

Learn about intermediate thyroid cancers like PDTC, High-Grade, and Hürthle Cell. Understand RAI-refractory treatments, targeted therapies, and redifferentiation.

06

Building Your Specialized Care Team

Learn how to build a specialized care team for rare thyroid cancers like ATC, MTC, and PDTC. Discover why high-volume centers and tumor boards are essential.

The Alphabet Soup: A Quick Glossary

Medical reports are full of acronyms. Here is a quick reference guide to help you navigate the jargon as you read your reports and this guide:

  • ATC: Anaplastic Thyroid Carcinoma (the fastest-growing and most aggressive form).
  • MTC: Medullary Thyroid Carcinoma (arises from C-cells, monitored by Calcitonin levels, often driven by RET mutations).
  • PDTC: Poorly Differentiated Thyroid Carcinoma (an “intermediate” aggressive cancer).
  • DHGTC: Differentiated High-Grade Thyroid Carcinoma (a new 2022 category for cancers with high mitotic rates).
  • HCC: Hürthle Cell Carcinoma (now officially renamed Oncocytic Carcinoma).
  • NGS: Next-Generation Sequencing (a genetic test to find the DNA mutations driving your cancer).
  • RAI: Radioactive Iodine (a standard treatment for common thyroid cancers, but often ineffective for rare types).
  • TKI: Tyrosine Kinase Inhibitor (a type of daily targeted therapy pill).

Common questions in this guide

What is a rare thyroid carcinoma?
Rare thyroid carcinoma is an umbrella term for several distinct and uncommon types of thyroid cancer. These include anaplastic, medullary, poorly differentiated, and oncocytic carcinomas, which each behave very differently from one another.
What is the difference between ATC and MTC thyroid cancer?
ATC stands for Anaplastic Thyroid Carcinoma, which is the fastest-growing and most aggressive form of thyroid cancer, considered a medical emergency. MTC stands for Medullary Thyroid Carcinoma, which arises from C-cells and is often driven by RET gene mutations.
Does radioactive iodine (RAI) work for rare thyroid cancers?
Radioactive iodine is a standard treatment for common thyroid cancers, but it is often ineffective for rare types. Your care team will likely use other approaches, such as targeted therapy pills called Tyrosine Kinase Inhibitors (TKIs), based on your specific diagnosis.
How do I find out what genetic mutations are driving my thyroid cancer?
Your doctor can order a test called Next-Generation Sequencing (NGS). This genetic test examines your tumor's DNA to identify the specific mutations driving your cancer, which helps your care team choose the most precise and effective treatments.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Based on my pathology report, exactly which of the rare thyroid carcinoma subtypes do I have?
  2. 2.Can you explain the specific genetic mutations driving my cancer in plain language?
  3. 3.Are there any immediate lifestyle or dietary changes I need to make while we await further test results?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (4)
  1. 1

    Updates on the Management of Thyroid Cancer.

    Araque KA, Gubbi S, Klubo-Gwiezdzinska J

    Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme 2020; (52(8)):562-577 doi:10.1055/a-1089-7870.

    PMID: 32040962
  2. 2

    Promising Therapeutic Targets for Recurrent/Metastatic Anaplastic Thyroid Cancer.

    Abdalla AS, Rahman M, Khan SA

    Current treatment options in oncology 2024; (25(7)):869-884 doi:10.1007/s11864-024-01219-y.

    PMID: 38862695
  3. 3

    Overview of the 2022 WHO Classification of Thyroid Neoplasms.

    Baloch ZW, Asa SL, Barletta JA, et al.

    Endocrine pathology 2022; (33(1)):27-63 doi:10.1007/s12022-022-09707-3.

    PMID: 35288841
  4. 4

    Endocrine and Neuroendocrine Tumors: Updates From the 5th Edition of the World Health Organization "Blue Book".

    Hernandez-Prera JC, Riddle N, Gonzalez RS, Asa SL

    Archives of pathology & laboratory medicine 2025; (149(12)):1114-1135 doi:10.5858/arpa.2024-0315-RA.

    PMID: 40335070

This guide is for informational purposes only and does not replace professional medical advice. Rare thyroid carcinomas are complex diseases; always consult your specialized oncology team regarding your specific diagnosis and treatment plan.

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