Salivary gland tumours
Epidemiology
[edit | edit source]- F>M
- Mostly 45-65yo
- 80% in parotid, 15% submandibular, others in minor salivary glands
Risk factors
[edit | edit source]- Pleomorphic adenoma - radiation
- Smoking - strong association with Warthin's
- Viral infections - HIV, EBV, HPV
- Environmental carcinogens
Aetiology
[edit | edit source]- Benign
- Pleomorphic adenoma (50% overall, and 80% of parotid)
- Slow-growing, painless mass, classically in tail of parotid
- Epithelial, myoepithelial (spindle cell) and stromal cell components
- Surrounded by fibrous capsule
- Can transform to malignancy, 10% risk in 15 years
- Warthin's tumour
- Papillary cystadenoma lymphomatosum
- Extremely low incidence of malignant transformation
- Soft cystic lump
- Can be either observed or resected
- Oncocytoma
- Similar to Warthin's
- Can excise
- Cystadenoma
- Basal cell adenoma
- Canalicular adenoma
- Pleomorphic adenoma (50% overall, and 80% of parotid)
- Malignant
- SCC
- Metastatic SCC is most common in Australia
- Mucoepidermoid carcinoma
- Common
- Invades locally and can recur
- Variable grade
- Adenoid cystic carcinoma
- Acinic cell carcinoma
- Polymorphous low-grade adenocarcinoma
- Carcinoma ex pleomorphic adenoma
- Metastases
- SCC
Presentation
[edit | edit source]- Usually painless mass
- Facial nerve paralysis suggests malignancy
- Cervical lymphadenopathy
- Parotid usually level II-IV
- Submandibular usually I-III
Examination
[edit | edit source]- Mass features
- Trismus
- Oral cavity
- Facial nerve examination
- Cervical LNs
- Skin or scalp lesions suggestive of primary malignancy
Investigation
[edit | edit source]- USS initially - should also do FNA
- Milan criteria 1-6 (same as Bethesda system)
- CNB is more accurate than FNA
- MRI if soft tissue invasion or nerve involvement suspected
- CT head/neck/chest
- PET often done
Staging
[edit | edit source]- TNM
| Primary tumor (T) | |||
| T category | T criteria | ||
| TX | Primary tumor cannot be assessed | ||
| T0 | No evidence of primary tumor | ||
| Tis | Carcinoma in situ | ||
| T1 | Tumor 2 cm or smaller in greatest dimension without extraparenchymal extension* | ||
| T2 | Tumor larger than 2 cm but not larger than 4 cm in greatest dimension without extraparenchymal extension* | ||
| T3 | Tumor larger than 4 cm and/or tumor having extraparenchymal extension* | ||
| T4 | Moderately advanced or very advanced disease | ||
| T4a | Moderately advanced disease.
Tumor invades skin, mandible, ear canal, and/or facial nerve. |
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| T4b | Very advanced disease.
Tumor invades skull base and/or pterygoid plates and/or encases carotid artery. |
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| * Extraparenchymal extension is clinical or macroscopic evidence of invasion of soft tissues. Microscopic evidence alone does not constitute extraparenchymal extension for classification purposes. | |||
| Regional lymph nodes (N) | |||
| Pathological N (pN) | |||
| N category | N criteria | ||
| NX | Regional lymph nodes cannot be assessed | ||
| N0 | No regional lymph node metastasis | ||
| N1 | Metastasis in a single ipsilateral lymph node, 3 cm or smaller in greatest dimension and ENE(–) | ||
| N2 | Metastasis in a single ipsilateral lymph node, 3 cm or smaller in greatest dimension and ENE(+); or
Larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(–); or Metastases in multiple ipsilateral lymph node(s), none larger than 6 cm in greatest dimension and ENE(–); or In bilateral or contralateral lymph nodes, none larger than 6 cm in greatest dimension and ENE(–) |
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| N2a | Metastasis in single ipsilateral node 3 cm or smaller in greatest dimension and ENE(+); or
A single ipsilateral node larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(–) |
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| N2b | Metastases in multiple ipsilateral nodes, none larger than 6 cm in greatest dimension and ENE(–) | ||
| N2c | Metastases in bilateral or contralateral lymph node(s), none larger than 6 cm in greatest dimension and ENE(–) | ||
| N3 | Metastasis in a lymph node larger than 6 cm in greatest dimension and ENE(–); or
In a single ipsilateral node larger than 3 cm in greatest dimension and ENE(+); or Multiple ipsilateral, contralateral, or bilateral nodes any with ENE(+); or A single contralateral node of any size and ENE(+) |
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| N3a | Metastasis in a lymph node larger than 6 cm in greatest dimension and ENE(–) | ||
| N3b | Metastasis in a single ipsilateral node larger than 3 cm in greatest dimension and ENE(+); or
Multiple ipsilateral, contralateral, or bilateral nodes any with ENE(+); or A single contralateral node of any size and ENE(+) |
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| NOTE: A designation of "U" or "L" may be used for any N category to indicate metastasis above the lower border of the cricoid (U) or below the lower border of the cricoid (L).
Similarly, clinical and pathological ENE should be recorded as ENE(–) or ENE(+). |
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| Distant metastasis (M) | |||
| M category | M criteria | ||
| M0 | No distant metastasis | ||
| M1 | Distant metastasis | ||
| Prognostic stage groups | |||
| When T is... | And N is... | And M is... | Then the stage group is... |
| Tis | N0 | M0 | 0 |
| T1 | N0 | M0 | I |
| T2 | N0 | M0 | II |
| T3 | N0 | M0 | III |
| T0, T1, T2, T3 | N1 | M0 | III |
| T4a | N0, N1 | M0 | IVA |
| T0, T1, T2, T3, T4a | N2 | M0 | IVA |
| Any T | N3 | M0 | IVB |
| T4b | Any N | M0 | IVB |
| Any T | Any N | M1 | IVC |
Management
[edit | edit source]- Benign
- Mostly superficial parotidectomy
- Conservative parotidectomy for small tumours, especially in inferior portion
- Malignant
- Resection, including nerve sacrifice if invasion
- High-grade:
- Total parotidectomy
- Adjuvant radiotherapy for high-risk cancers
- Neck dissection: prophylactic if high-risk factors, or therapeutic if confirmed nodal invasion
- Low-grade:
- Superficial parotidectomy
- Adjuvant chemotherapy role not defined
- Recurrence:
- Salvage resection vs radiotherapy vs palliation
- Palliative systemic therapy has a low response rate