---
title: "Anaplastic Thyroid Carcinoma"
description: "ENT notes on Anaplastic Thyroid Carcinoma - Risk factors, Clinical Features, Histology, Investigations and Treatment."
source: "The ENT Resident"
author: "Dr. Mausumi Das"
canonical_url: "https://www.theentresident.com/ent-notes-lectures/anaplastic-thyroid-carcinoma"
categories: ["Thyroid"]
video: "https://www.youtube.com/watch?v=0v7WrJOfYg8"
image: "https://media.theentresident.com/og-images/anaplastic-thyroid-carcinoma.png"
---

# Anaplastic Thyroid Carcinoma

ENT notes on Anaplastic Thyroid Carcinoma - Risk factors, Clinical Features, Histology, Investigations and Treatment. Watch the full video lecture on YouTube: https://www.youtube.com/watch?v=0v7WrJOfYg8

### 📊 Epidemiology of Anaplastic Thyroid Carcinoma

| Feature | Details |
| --- | --- |
| **Incidence** | ~5% of all thyroid malignancies |
| **Age group** | 60–80 years (very rare before 50 years) |
| **Sex** | Female : Male = **3 : 2** |
| **Origin** | Undifferentiated carcinoma arising from **follicular epithelium** |
| **Mortality** | Very high; **median survival 3–5 months** |

---

### ⚠️ Etiology & Risk Factors of Anaplastic Thyroid Carcinoma

- Previous neck radiation exposure
- Pre-existing multinodular goiter
- Pre-existing differentiated thyroid carcinoma
- Iodine deficiency
- Genetic mutations

>What are the genetic mutations seen in Anaplastic Thyroid Carcinoma?

---

## 🩺 Clinical Features of Anaplastic Thyroid Carcinoma

| Feature | Description |
| --- | --- |
| **Onset** | Often arises in a long-standing multinodular goiter or papillary carcinoma |
| **Nature** | **Rapidly enlarging, painful**, hard, ill-defined anterior neck mass |
| **Fixity** | Fixed to underlying structures |
| **Pain** | Common |
| **Surface** | Irregular, nodular |
| **Consistency** | Hard, woody |
| **Local invasion (70%)** | Muscles, trachea, esophagus, larynx, recurrent laryngeal nerve |
| **Symptoms of invasion** | Dyspnea, stridor, dysphagia, hoarseness, referred otalgia |
| **Cervical nodes** | Involved in **~80%** at presentation |
| **Distant metastasis** | Seen in **30–50%** |

>What is the most common site of distant metastasis in Anaplastic thyroid carcinoma?

> 🚩 Painful thyroid swelling in an elderly patient → think **Anaplastic carcinoma**.  

---

### 🧬 Staging (AJCC/UICC) of Anaplastic Thyroid Carcinoma

> 🚩 All anaplastic carcinomas are **Stage IV** at presentation.

| Stage | Description |
| --- | --- |
| **Stage IVA** | Tumor confined to thyroid |
| **Stage IVB** | Extrathyroidal extension (local invasion) |
| **Stage IVC** | Distant metastasis |

---

### 🔬 Histopathology of Anaplastic Thyroid Carcinoma

**Origin:** Undifferentiated tumor of follicular epithelium.

**Common Histological Variants**

| Type | Features |
| --- | --- |
| **Epithelioid (Pleomorphic)** | Giant cells, bizarre nuclei |
| **Sarcomatoid** | Spindle-shaped cells, most common |
| **Others (rare)** | Angiomatoid, osteoclastic, rhabdoid, lymphoepithelioma-like, carcinosarcomatoid, adenosquamous, fibrosing types |

#### Key Microscopic Findings

- Giant and spindle cells  
- Atypical mitosis  
- Extensive necrosis  
- Inflammatory infiltrate  
- Angio-lymphatic invasion

>What is the most common histological subtype in Anaplastic Thyroid Carcinoma?

---

### 🧪 Investigations of Anaplastic Thyroid Carcinoma

| Investigation | Findings / Purpose |
| --- | --- |
| **FNAC** | Confirms undifferentiated malignant cells |
| **Ultrasound Neck** | Large, ill-defined, hypoechoic solid mass with extrathyroidal spread |
| **Contrast enhanced CT (Neck + Mediastinum)** | Heterogeneously enhancing mass, infiltrating thyroid and adjacent structures; necrosis/hemorrhage → central hypodensity |
| **MRI (Neck)** | For staging & local invasion |
| **Chest X-ray / CT Chest** | To detect lung metastasis (MC site) |
| **Bone Scan** | Detects osseous metastasis |

>What is the Investigation of choice in Anaplastic Thyroid Carcinoma?

---

### 🏥 Treatment of Anaplastic Thyroid Carcinoma

Treatment is largely **palliative**, as the tumor is highly aggressive with poor prognosis.

1️⃣ **Resectable Locoregional Disease**

- **Total thyroidectomy** + **central and lateral neck dissection**
- Avoid extensive ablative procedures (e.g. total laryngectomy)
- **Tracheostomy** if airway compromised (dyspnea/stridor)
- **Adjuvant therapy:** External beam radiotherapy

2️⃣ **Unresectable Disease**

- Surgery not possible due to extensive invasion.

**Treatment Options:**
- **Chemoradiation:**  
  - Radiation: **60–70 Gy** (hyperfractionated, 40–45 fractions / 5–6 weeks)  
  - Palliative doses: 20 Gy × 5 fractions (repeat in 4–6 weeks) or 30 Gy × 10 fractions  

>What drugs are used for chemotherapy in Anaplastic thyroid carcinoma?  

> 💡 Anaplastic Thyroid Carcinoma is generally **chemoresistant**, so drugs are used mainly to enhance radiosensitivity.

3️⃣ **Metastatic Disease**

- **Palliative therapy** aimed at symptom relief and maintaining quality of life.
- Short 1–2 week course of palliative radiotherapy.

---

### 📉 Prognosis of Anaplastic Thyroid Carcinoma

| Feature | Prognostic Significance |
| --- | --- |
| **Overall outlook** | Extremely poor |
| **Median survival** | ~4 months |
| **5-year survival** | < 10% |
| **Death** | Usually within 1–2 years of diagnosis |

> ⚠️ Even with aggressive therapy, median survival remains < 6 months.

>What are the poor prognostic factors in Anaplastic Thyroid Carcinoma?

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## About This Note

This free ENT note on Anaplastic Thyroid Carcinoma was written by Dr. Mausumi Das and is paired with a corresponding video lecture.

Canonical page of this note: https://www.theentresident.com/ent-notes-lectures/anaplastic-thyroid-carcinoma

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- Thyroid: https://www.theentresident.com/ent-notes-lectures/category/thyroid.md

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