Benign Salivary Gland Tumors

🦷 Benign Salivary Gland Tumors

📊 Incidence of Benign Salivary Gland Tumors

• Parotid - most common site: ~80% of all salivary neoplasms.

• Submandibular — ~ 15% of salivary tumours.

• Minor & Sublingual glands — together ~ 5%.

Which salivary gland has the highest chances of malignancy?

What is the most common benign salivary gland tumor?

What is the most common site of pleomorphic adenoma?

Common age: 4th–6th decades (peak around the 6th decade).

Gender: overall female predominance for salivary gland tumours

Which benign salivary gland tumor is predominantly in men?

🧬 Etiology / Risk Factors of Benign Salivary Gland Tumors

• Prior head & neck irradiation

• Smoking

• Viral infections — e.g., HPV-16 associations reported.

• Hormonal influences

• Occupational/environmental exposures — rubber, asbestos, woodworking, plumbing (associations reported)

• Chronic irritation/trauma

Which benign salivary gland tumor is associated with smoking?

🩺 Clinical Features of Benign Salivary Gland Tumors

• Most benign tumours are slow-growing, painless, smooth, mobile swellings.

• Lack of pain and preserved mobility are suggestive of benignity.

• Symptoms from mass effect possible (e.g., deep lobe parotid masses → oropharyngeal/parapharyngeal swelling, stertor, voice change, Eustachian tube dysfunction).

Parotid

• Firm swelling around angle of mandible / pre- and retromandibular region; may extend anterior to tragus or into cheek.

• Superficial lobe lesions present as external swelling.

• Deep lobe lesions may present as intra-oral / parapharyngeal swelling.

Submandibular gland

• Swelling in submandibular triangle

How can you differentiate a swelling involving submandibular gland from submandibular lymph node?

Minor Salivary Glands

• Palate, lips, buccal mucosa, floor of mouth — present as firm submucosal swelling; ulceration is uncommon unless traumatized.

What is the most common site of Minor Salivary Gland tumor?

🚩 Red Flags Suggesting Malignant Transformation

• Pain

• Rapid growth or sudden increase in growth rate

• Paresthesia / numbness

• Facial nerve palsy (parotid) or other cranial nerve deficits

• Fixity to skin / deep structures, skin ulceration or irregular surface

• Firm, irregular, non-mobile lesion

🧾 WHO Classification of Benign Salivary Gland Tumors

• Epithelial tumours (common)

  • Pleomorphic adenoma

  • Warthin tumor

  • Oncocytoma (oxyphilic adenoma)

  • Myoepithelioma

  • Basal cell adenoma (monomorphic adenoma subgroup)

  • Canalicular adenoma

  • Other ductal/sebaceous adenomas

What is the other name of Warthin tumor?

• Mesenchymal tumours (less common)

  • Hemangioma, lymphangioma, lipoma, neurofibroma, schwannoma, chondroma, osteoma

Oncocytoma (Oxyphilic adenoma)

• Frequency: < 1% of salivary tumours.

• Cell of origin: oncocytes

• Age: older adults (7th–8th decade).

• Site: superficial parotid common.

• Gross/histo: well-circumscribed, encapsulated; oncocytes; tyrosine crystals may be seen.

• Special: Increased uptake on Tc-99m scintigraphy.

• Treatment: Superficial parotidectomy; low recurrence (recurrence usually due to multifocal nodules).

What are Oncocytes?

Myoepithelioma

• Arises from myoepithelial cells; rare; may affect any salivary gland; age range variable.

• Treated similar to pleomorphic adenoma (surgical excision).

Basal Cell Adenoma / Canalicular Adenoma

• Basal cell adenoma: monomorphic basaloid cells in solid/trabecular/tubular/membranous patterns.

• Canalicular adenoma: variant with bilayered ribbon-like columnar cells separated by vascular stroma (common in minor glands).

Hemangioma

• Present at birth or early infancy; rapid growth phase then spontaneous involution in many cases.

• Management: often conservative; excision if persistent/problematic.

Lymphangioma

• Cystic, soft, congenital; does not involute reliably → usually surgical excision.

What is the Most common benign parotid tumour in children?

🧪 Investigations of Benign Salivary Gland Tumors

1- Ultrasound (first-line)

• Distinguishes solid vs cystic, intra- vs extra-glandular, vascularity.

• Useful for USG-guided FNAC to improve sampling accuracy.

2- CT / MRI

What are the indications of CT and MRI in Benign Salivary Gland Tumors?

What is the gold standard investigation for Benign Salivary Gland Tumors?

3- Fine Needle Aspiration Cytology (FNAC)

• Diagnostic accuracy around ~90% for distinguishing benign vs malignant when combined with imaging.

• USG-guided FNAC increases yield.

4- Core Needle Biopsy

• Generally avoided for salivary tumours due to risk of tumour seeding and potential facial nerve injury; reserved for selected cases when FNAC is inconclusive and results would change management.

5- Sialography

• Historical; rarely used now. May show ductal filling defects.

6- Scintigraphy (Tc-99m pertechnetate)

• Warthin tumour often shows a hotspot.

Why does Warthin tumor show hotspots on scintigraphy?

🛠 Treatment Principles of Benign Salivary Gland Tumors

• Surgery is the definitive treatment for benign salivary tumours.

• No role for radiotherapy/chemotherapy in benign disease.

What are the factors influencing surgical approach to Benign Salivary Gland Tumors?

1️⃣ Parotid tumours

• Superficial parotidectomy - indicated when tumour confined to superficial lobe; preserve facial nerve.

• Total conservative parotidectomy (both lobes removed but facial nerve preserved) - indicated for deep lobe involvement, large dumbbell tumours, or if tumour spillage occurs during surgery.

2️⃣ Submandibular gland

• Total excision of the gland with tumour
• Sample adjacent nodes if suspicious.

3️⃣ Sublingual gland

• Excision of gland via intraoral approach

4️⃣ Minor salivary glands

• Wide local excision with margin of normal tissue (e.g., palatal tumours down to periosteum).

• Reconstruction (local flap / obturator / mucosal repair) as required.

🩺 Follow-up & Recurrence of Benign Salivary Gland Tumors

• Regular follow-up is important (clinical exam ± imaging when indicated).

• Pleomorphic adenoma has notable recurrence risk if tumour capsule violated or incomplete excision; recurrence may occur years later - long-term follow-up recommended.