--- title: "Malignant Salivary Gland Tumors" description: "Comprehensive ENT notes on Malignant Salivary Gland Tumors - Causes, WHO Classification, Symptoms, Investigations and Treatment - ideal for MBBS and ENT students." source: "The ENT Resident" canonical_url: "https://www.theentresident.com/ent-notes-lectures/malignant-salivary-gland-tumors" categories: ["Oral Cavity and Salivary Glands"] video: "https://www.youtube.com/watch?v=raJAxBdBC8c" image: "https://media.theentresident.com/og-images/malignant-salivary-gland-tumors.png" --- # Malignant Salivary Gland Tumors Comprehensive ENT notes on Malignant Salivary Gland Tumors - Causes, WHO Classification, Symptoms, Investigations and Treatment - ideal for MBBS and ENT students. Watch the full video lecture on YouTube: https://www.youtube.com/watch?v=raJAxBdBC8c ## 🧬 Malignant Salivary Gland Tumors Malignant salivary gland tumors are **uncommon head and neck malignancies** with diverse histology, variable clinical behavior, and complex management strategies. Understanding their **risk factors, histogenesis, clinical presentation, staging, classification, investigations, and treatment** is essential for ENT examinations and clinical practice. --- ### 📌 Incidence & Epidemiology of Malignant Salivary Gland Tumors - Incidence: **~0.5 per 1 lakh population per year** - Account for **< 5% of all head and neck cancers** - Less common than **benign salivary gland tumors** - Incidence increases **after the 5th decade of life** --- ### ⚠️ Risk Factors for Malignant Salivary Gland Tumors **1️⃣ Radiation Exposure (Most Important)** - **Atomic bomb survivors** - Increased risk of **mucoepidermoid carcinoma** - **Therapeutic head & neck radiation** - Especially childhood cancers > What is the usual latent period between radiation exposure and development of Malignant Salivary Gland Tumors? **2️⃣ Occupational Exposure** Increased risk with exposure to: - Rubber - Nickel - Asbestos - Silica dust - Plumbing, woodworking, mining industries 📌 **Livestock feed processing** - Exposure to **mycotoxins** (produced by *Aspergillus*) - Highly carcinogenic **3️⃣ Viral Associations** (Not conclusively proven) - **Epstein–Barr virus (EBV)** → Undifferentiated parotid carcinoma - **Cytomegalovirus (CMV)** → Mucoepidermoid carcinoma **4️⃣ Nutritional Factors** - **Inverse relationship** with diet rich in **polyunsaturated fatty acids** - Higher PUFA intake → lower salivary gland cancer risk **5️⃣ Genetic & Molecular Alterations** - **Mucoepidermoid carcinoma** → *CRTC1–MAML2* gene fusion - **Adenoid cystic carcinoma** → *MYB–NFIB* gene fusion --- ### 🧠 Histogenesis of Malignant Salivary Gland Tumors 🔹 **1. Multicellular Theory** (Older) Each tumor arises from a **specific mature cell type** of the salivary gland. | Cell of Origin | Tumor Type | | --- | --- | | Acinar cells | Acinic cell carcinoma | | Intercalated duct cells | Adenoid cystic carcinoma, Polymorphous adenocarcinoma | | Excretory duct cells | Mucoepidermoid carcinoma, Salivary duct carcinoma, SCC | | Myoepithelial cells | Myoepithelial carcinoma, Basal cell adenocarcinoma | > ➡️ Multiple cells of origin → **multicellular theory** 🔹 **2. Reserve Cell (Stem Cell) Theory** (Most Accepted) - All tumors arise from a **single undifferentiated pluripotent reserve cell** - Normal salivary gland & tumors arise via **differentiation** - **Earlier differentiation error → higher grade malignancy** >➡️ Reserve Cell Theory explains wide histological diversity > What is the risk (%) of malignancy in Parotid, submandibular, sublingual and Minor salivary glands? 📌 **Smaller the gland → higher the malignancy risk** --- ### 🩺 Clinical Features of Malignant Salivary Gland Tumors #### 🔹 Parotid Gland - Painless pre-/infra-auricular swelling - **Deep lobe tumors** → soft palate / oropharyngeal bulge - **Accessory parotid tumors**: ~1% > What is the most common site of origin of malignant salivary gland tumor in Parotid? > What are the Features Suggestive of Malignancy in a parotid malignancy? #### 🔹 Submandibular Gland - Slow-growing painless swelling in submandibular triangle - May distort floor of mouth - Pain (30%), cervical nodes (25%) > What are the common nerves involved in malignant salivary gland tumor in Submandibular Gland? #### 🔹 Minor Salivary Glands - Can arise anywhere - Painless submucosal swelling - Central ulceration - Ill-fitting dentures (important clue) - Pain / paresthesia (~25%) > What is the most common site of origin of malignant salivary gland tumor in Minor Salivary Glands? --- ### 🧪 TNM Staging (Salivary Gland Tumors) **T Staging** - **T1:** ≤ 2 cm, no extraparenchymal extension - **T2:** > 2–4 cm, no extraparenchymal extension - **T3:** > 4–6 cm and/or extraparenchymal extension - **T4a:** Tumor invades Skin, mandible, ear canal, and/or facial nerve - **T4b:** Tumor invades Skull base, and/or pterygoid plates, and/or encases carotid artery **N Staging** - **N1:** Single ipsilateral node ≤ 3 cm, no extranodal extension - **N2a:** Single ipsilateral node > 3–6 cm, no extranodal extension - **N2b:** Multiple ipsilateral < 6 cm - **N2c:** Bilateral/contralateral < 6 cm - **N3a:** > 6 cm, no extranodal extension - **N3b:** Any node with extranodal extension **M Staging** - **M0:** No distant metastasis - **M1:** Distant metastasis --- ### 🧬 Classification of Malignant Salivary Gland Tumors **22 malignant salivary gland tumor types**, common ones include: - Mucoepidermoid carcinoma - Adenoid cystic carcinoma - Acinic cell carcinoma - Polymorphous adenocarcinoma (formerly PLGA) - Salivary duct carcinoma - Myoepithelial carcinoma - Carcinoma ex-pleomorphic adenoma - Squamous cell carcinoma - Neuroendocrine carcinomas - Lymphoepithelial carcinoma - Sialoblastoma --- ### 🔸 Acinic Cell Carcinoma - Low-grade tumor (~3%) - 90% parotid - Female predominance - Encapsulated, solid/microcystic patterns - Rare facial nerve or nodal involvement --- ### 🔸 Polymorphous Adenocarcinoma - Minor salivary glands (palate) - Low-grade, indolent - Late recurrence (10–15 years) - Mimics pleomorphic adenoma & adenoid cystic carcinoma --- ### 🔸 Adenocarcinoma (NOS) - Aggressive - Perineural invasion - Facial nerve involvement (~20%) - Poor prognosis --- ### 🔸 Carcinoma ex-Pleomorphic Adenoma - Malignancy in pre-existing pleomorphic adenoma - Risk increases with duration - Poor prognosis --- ### 🔍 Investigations of Malignant Salivary Gland Tumors **A. Imaging** - **Ultrasound**: First line + FNAC guidance - **CECT**: Large tumors, nerve involvement, nodes - **MRI**: Best soft-tissue delineation, perineural spread - **PET-CT**: Staging (false positives in Warthin’s & pleomorphic adenoma) **B. Cytology** - **FNAC** – initial test - **Core biopsy** – if FNAC inconclusive --- ### 🛠️ Treatment of Malignant Salivary Gland Tumors #### 🔹 Surgery (Mainstay) **A. Parotid** - Superficial parotidectomy - Total / Radical parotidectomy > What are the indications of Superficial parotidectomy & Total / Radical parotidectomy in Malignant Parotid Tumors? > What are the indications of Facial nerve resection in Malignant Parotid Tumors? --- **B. Submandibular Gland** - Early, N0 → Gland excision + Level I - Advanced → Levels I–III or comprehensive neck dissection --- **C. Sublingual & Minor Salivary Glands** - Wide local excision - N-block resection for large tumors - Elective neck dissection often indicated --- **🔹 Neck Management** - **Clinically N+** → Modified radical neck dissection - **Pathologically N+** → Adjuvant radiotherapy - **Clinically N0** → Elective neck treatment if high-risk --- #### ☢️ Adjuvant Radiotherapy in Malignant Salivary Gland Tumors **Indications:** - T3–T4 tumors - High-grade histology - Perineural / vascular invasion - Positive margins - Multiple nodes --- #### 💊 Chemotherapy in Malignant Salivary Gland Tumors - Limited role - Palliative - Best response in adenocarcinoma NOS - Drugs: Cisplatin, Doxorubicin, Cyclophosphamide --- ### 📌 Exam Pearls - **Smaller gland → higher malignancy risk** - Facial nerve palsy = malignancy until proven otherwise - MRI best for perineural spread - Surgery is the cornerstone of treatment - Radiotherapy is adjuvant, chemotherapy mostly palliative --- ## About This Note This note on Malignant Salivary Gland Tumors is one of the free ENT study notes published by The ENT Resident. It is free to read on the website, and it is paired with a full video lecture on YouTube. This note is categorized under [Oral Cavity and Salivary Glands](https://www.theentresident.com/ent-notes-lectures/category/oral-cavity-and-salivary-glands.md). The category page lists all the free ENT notes on that topic. Canonical page of this note: https://www.theentresident.com/ent-notes-lectures/malignant-salivary-gland-tumors When citing or referencing this content, please credit The ENT Resident and link to the canonical page above. ## About The ENT Resident The ENT Resident is a free library of ENT notes and video lectures created by Dr. Mausumi Das (MS ENT), the ENT doctor and educator behind The ENT Resident YouTube channel (https://www.youtube.com/c/TheENTResident). These notes are written for ENT residents, ENT postgraduates preparing for exams, and MBBS students, to help them learn ENT clearly and score well. 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Other contact options are on the contact page: https://www.theentresident.com/contact.md ## Related ENT Notes & Lectures #### Oral Cavity and Salivary Glands - [Adenoid Cystic Carcinoma](https://www.theentresident.com/ent-notes-lectures/adenoid-cystic-carcinoma-histology-treatment.md) - [Anatomy of Parotid Gland](https://www.theentresident.com/ent-notes-lectures/parotid-gland-anatomy.md) - [Anatomy of Submandibular and Sublingual Glands](https://www.theentresident.com/ent-notes-lectures/submandibular-sublingual-gland-anatomy.md) - [Anatomy of the Tongue](https://www.theentresident.com/ent-notes-lectures/tongue-anatomy.md) - [Benign Salivary Gland Tumors](https://www.theentresident.com/ent-notes-lectures/benign-salivary-gland-tumors.md) - [Development of the Tongue](https://www.theentresident.com/ent-notes-lectures/development-of-tongue.md) - [Developmental Anomalies of the Tongue](https://www.theentresident.com/ent-notes-lectures/developmental-anomalies-of-tongue.md) - [Lymphatic Drainage of Tongue](https://www.theentresident.com/ent-notes-lectures/lymphatic-drainage-tongue.md) - [Mucoepidermoid Carcinoma](https://www.theentresident.com/ent-notes-lectures/mucoepidermoid-carcinoma-histology-treatment.md) - [Muscles of Tongue](https://www.theentresident.com/ent-notes-lectures/muscles-of-tongue.md) - [Nerve Supply of Tongue](https://www.theentresident.com/ent-notes-lectures/nerve-supply-tongue.md) - [Pleomorphic Adenoma](https://www.theentresident.com/ent-notes-lectures/pleomorphic-adenoma-histology-treatment.md) - [Relations of Hyoglossus Muscle](https://www.theentresident.com/ent-notes-lectures/hyoglossus-muscle-relations.md) - [Warthin Tumor](https://www.theentresident.com/ent-notes-lectures/warthin-tumor-histology-treatment.md) --- Complete index of all pages on this site, with descriptions and markdown links: https://www.theentresident.com/llms.txt