Mucoepidermoid carcinoma

Most common salivary gland malignancy

Origin: Interlobular and intralobular tissue of salivary duct system

Site: Parotid gland and palate

Clinical: Pain and ulceration

Histology:

• Large pale mucous secreting cells surrounded by epidermoid (squamous) cells

Low grade tumor:

• Well differentiated cells
• > 50% mucus cells
• Cystic
• Good prognosis

High grade tumor:

• Poorly differentiated cells
• < 10% mucus cells
• Solid
• Poor prognosis

Management:

• Wide excision
• Can recur

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Polymorphous low grade adenocarcinoma

Origin: Proximal salivary duct cells

Site: Minor glands in palate

Clinical: Asymptomatic submucosal mass

Histology:

• Homogenous appearance of cells + vesicular nuclei + scanty cytoplasm
• Arranged in solid, streaming or pseudo cribriform patterns

Management: Conservative excision

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Adenoid cystic carcinoma

High grade malignancy

Site: Minor salivary glands

Clinical:

• Pain and ulceration
• Perineural invasion – paralysis
• Distant metastasis to lungs

Histology:

• Neoplastic epithelium in ovoid/irregularly arranged islands
• Numerous microcytic spaces within islands – “Swiss cheese” or “cribriform” pattern
• Solid/tubular pattern – poor prognosis

Management:

• Complete excision
• Chemotherapy, radiotherapy
• Nerve grafting
• Can recur

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Clear cell carcinoma

Low grade tumor affecting minor glands

Site: Palate

Clinical: Submucosal mass

Histology: Clear cell change due to – cytoplasmic accumulation of glycogen and microfilaments

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Acinic cell carcinoma

Origin: Duct reserve cells + acinic cells

Site: Parotid gland

Clinical: Mimics adenoma

Histology:

• Blue dot tumor
• Sheets/acini of large polyhedral cells + basophilic granular cytoplasm

Management:

• Aggressive excision
• Poor prognosis for poorly differentiated

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Unspecific adenocarcinoma

Site: Salivary epithelium

• Non specific features, a diagnosis of elimination

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CA in PSA

Origin: Untreated long standing pleomorphic adenoma. Malignant mixed tumor

Site: 68% from parotid

Histology: Neoplastic change in mixed tissues

Management:

• Aggressive surgical resection
• Poor prognosis