Salivary Gland Neoplasms

Salivary Glands 101 - Anatomy & Adversaries

• Major Glands & Secretion Types: Parotid (Serous), Submandibular (Mixed), Sublingual (Mucous) - 📌 PSM SM M
  • Parotid: Largest. Duct: Stensen's.
    • Facial nerve (CN VII) traverses (no innervation).
  • Submandibular: Duct: Wharton's.
  • Sublingual: Smallest. Ducts: Bartholin's, Rivinus.
• Minor Glands: Numerous, in oral mucosa (e.g., von Ebner's).
• WHO Classification (Epithelial Neoplasms):
  • Benign:
    • Pleomorphic Adenoma (most common overall).
    • Warthin's Tumor (papillary cystadenoma lymphomatosum).
  • Malignant:
    • Mucoepidermoid Carcinoma (most common malignant).
    • Adenoid Cystic Carcinoma (ACC) (perineural invasion).
    • Acinic Cell Carcinoma.
    • Carcinoma ex Pleomorphic Adenoma (Ca ex PA).

⭐ Frey's syndrome (gustatory sweating): post-parotidectomy complication due to auriculotemporal nerve misdirection.

Benign Beauties - Mostly Harmless Masses

• Pleomorphic Adenoma (Benign Mixed Tumor)

  • Most common salivary gland tumor overall.
  • Can present as 'Dumbbell tumor' (parapharyngeal space).
  • Histology: epithelial & myoepithelial cells in varied stroma (e.g., chondromyxoid).
  • Slow-growing, painless mass.
  • Malignant transformation risk (Carcinoma ex PA): ~1.5% up to 5 yrs, ~9.5% after 15 yrs.

  ⭐ Pleomorphic adenoma is the most common salivary gland tumor, accounting for about 80% of benign parotid tumors.

• Warthin's Tumor (Papillary Cystadenoma Lymphomatosum)

  • Almost exclusively in parotid gland; common in elderly males, smokers.
  • Often bilateral (10%).
  • Histology: papillary cystic structures lined by oncocytic epithelium with a lymphoid stroma.
  • 📌 Warthin's = Warriors (lymphoid) in old Smoking Men.

Malignant Mayhem - When Glands Go Rogue

• Mucoepidermoid Carcinoma (MEC)
  • Most common malignant tumor overall & in children.
  • Parotid: most common site.
  • Histology: mucous, epidermoid, intermediate cells.
  • Graded: Low, Intermediate, High (prognostic).
• Adenoid Cystic Carcinoma (ACC)
  • Notorious for perineural invasion (PNI), late distant metastases (lungs).
  • Histology: cribriform ('Swiss cheese'), tubular, solid patterns.
  • 📌 ACC = Always Creeps around Cranial nerves.
  • 5-year survival ~75%, 15-year ~40% due to late mets.

  ⭐ Perineural invasion is a characteristic feature of Adenoid Cystic Carcinoma, often leading to pain and poor prognosis.

• Acinic Cell Carcinoma
  • Low-grade malignancy.
  • Good prognosis.
  • Histology: serous acinar differentiation.
• Carcinoma ex Pleomorphic Adenoma
  • Malignancy arising in a pre-existing Pleomorphic Adenoma (PA).
  • Often aggressive; prognosis depends on extent of invasion and grade of carcinoma component.

Clinical Clues & Cures - Spotting & Stopping

• Clinical Presentation:
  • Painless swelling (most common).
  • Malignancy signs: Pain, facial nerve palsy (VII), rapid growth, skin ulceration, cervical lymphadenopathy.
  • 📌 Red Flags: Pain, Palsy, Puckering, Progression (Rapid).
• Investigations:
  • FNAC - initial diagnostic test (Accuracy >90% malignancy).
  • Imaging: USG (solid/cystic), CT/MRI (extent, PNI, bone invasion, deep lobe).
• Staging:
  • TNM (AJCC) - Tumor size/extent (T), Nodal involvement (N), Metastasis (M).
• General Management Principles:
  • Surgery (cornerstone).
  • Radiotherapy (adjuvant for high-grade, +margins, PNI, recurrent; primary for inoperable).
  • Chemotherapy (palliative/advanced).

⭐ FNAC is the investigation of choice for a palpable salivary gland mass, guiding further management.

High‑Yield Points - ⚡ Biggest Takeaways

• Pleomorphic adenoma is the most common salivary gland tumor, overwhelmingly benign.
• Mucoepidermoid carcinoma stands as the most common malignant salivary tumor.
• Parotid gland is the most frequent site; tumors here are predominantly benign (80% rule).
• Submandibular and minor salivary glands exhibit a significantly higher risk of malignancy.
• Adenoid cystic carcinoma is notorious for perineural invasion and late distant metastases.
• Facial nerve palsy accompanying a parotid mass strongly suggests malignancy.
• Warthin's tumor: Almost exclusive to parotid, strongly linked to smoking, often bilateral.