Warthin Tumor

🧬 Warthin’s Tumor (Papillary Cystadenoma Lymphomatosum)

📌 Definition of Warthin’s Tumor

Warthin’s tumor is a benign salivary gland tumor composed of two characteristic components:

1. Oncocytic epithelial cells lining papillary and cystic ductal structures
2. Lymphoid stroma, often with germinal centers

➡️ The presence of both oncocytic epithelium and lymphoid tissue is diagnostic.

What are the other two names for Warthin's Tumor? Why is it called so?

What are Oncocytes? What does it's typical appearance look like?

🧠 Epidemiology of Warthin’s Tumor

• Arises exclusively from the parotid gland

• Accounts for 5–10% of parotid tumors

• Common age group: 6th–7th decade

• 🚩 Only salivary gland tumor with male preponderance

• Usually unifocal

What % of Warthin tumors are multifocal & bilateral?

Which is the most common benign salivary gland tumor?

Which is the second most common benign salivary gland tumor?

📍 Site of Origin of Warthin’s Tumor

• Parotid gland only

➡️ This exclusive parotid involvement is an important MCQ.

Which is the most common site of origin of Warthin tumor in th eparotid gland?

🚬 Risk Factors of Warthin’s Tumor

1️⃣ Cigarette Smoking

• Strongest association

• ~8 times higher risk in smokers compared to non-smokers

• 🚩 Only salivary gland tumor strongly linked to smoking

2️⃣ Viral Association

Which virus is associated with warthin's tumor?

3️⃣ Radiation Exposure

• Seen in atomic bomb survivors
• Prior radiation exposure is a risk factor

🧠 Histogenesis (Pathogenesis) of Warthin’s Tumor

1️⃣ Heterotopia Theory (Most Accepted)

• During embryogenesis, salivary epithelial inclusions get trapped within Intra-parotid or peri-parotid lymph nodes

• These epithelial inclusions later proliferate → oncocytic epithelium

• The surrounding lymph node tissue forms the lymphoid stroma

How does the Heterotopia theory explain key features of Warthin Tumor?

2️⃣ Immunological Theory (Alternative)

• Lymphoid stroma represents a reactive immune response

• Against oncocytic epithelial proliferation

🔍 Gross (Macroscopic) Pathology of Warthin’s Tumor

• Well-circumscribed

• Encapsulated

• Smooth, soft mass

Cut Section shows :-

• multiple cystic spaces

• Filled with brown, viscous fluid

• Often described as having “machine oil” or “motor oil” appearance

🔬 Microscopic (Histological) Features of Warthin’s Tumor

1️⃣ Cystic Spaces

• Multiple cystic cavities

• Filled with:

  • Proteinaceous material
  • Cellular debris

2️⃣ Epithelial Lining

• Papillary projections into cystic spaces

• Lined by bilayered oncocytic epithelium:

Describe the morphology of the bilayered oncocytic epithelium.

3️⃣ Lymphoid Stroma

• Dense lymphoid tissue

• Often shows germinal centers

🩺 Clinical Features of Warthin’s Tumor

• Slow-growing

• Painless

• Well-defined mass

• Usually cystic and fluctuant

• Size rarely exceeds 3–4 cm

What are some rare symptoms seen in Warthin Tumor?

What is the rate of malignant transformation in Warthin Tumor?

🔎 Investigations of Warthin’s Tumor

1️⃣ Ultrasound (First-line)

• Differentiates:

  • Solid vs cystic
  • Intraglandular vs extraglandular lesions

• Useful for FNAC guidance

2️⃣ FNAC

• Most commonly used diagnostic test

• Helps differentiate benign vs malignant lesions

3️⃣ Scintigraphy (Characteristic Investigation)

What does the Technetium-99m pertechnetate scan show in Warthin's tumor? Explain why.

🩻 Treatment of Warthin’s Tumor

• Surgical excision

• Procedure of choice:- Partial superficial parotidectomy

• Tumor removed along with superficial lobe

• Facial nerve identified and preserved

Prognosis of Warthin’s Tumor

• Excellent
• Recurrence: rare

📌 Exam Pearls

• Second most common benign salivary gland tumor
• Only parotid tumor with:
  • Male predominance
  • Strong smoking association
• Only salivary tumor showing Tc-99m hot uptake
• Bilayered oncocytic epithelium + lymphoid stroma = Warthin’s tumor