Pathology of SG Tumours Flashcards
Why changes in gland size?
- secretion retention
- mucocele
- duct obstruction - chronic sialadenitis
- gland hyperplasia; sometime people with eating disorder
- Sialosis
- Sjogren syndrome - Salivary neoplasms
**Mumps will cause SG enlargement
What is Sialosis?
- refer BISOM
- can be known as sialadenosis
- painless swelling of parotid glands on both sides of face
- equally affecting both male and female
- 30-70 yrs of age
- may be due to abnormal nerve function that stimulates salivary glands
Changes in SG that leads to neoplasm?
- salivary tumours
- major gland: localised swelling
- may involve facial nerve in parotid gland
- usually painless
- slow growing
- well defined
Epidemiology of SGT
- uncommon
- mostly in adults
- 10 per 100 000
- 3% of H&N neoplasm
- 75% benign
- increasing malignant SGT
Aetiology of SGT
- unclear
- might be radiation from phones?
- racial?
- viruses?
Distribution of tumours
- differs in different journal/ papers
- Most tumour/ malignancy arise from sublingual gland (80%)
Histological typing
WHO classification 2017
- Epithelial neoplasm
- 11 types of benign (adenoma)
- 20 types of malignant (adenocarcinoma) - Non-epithelial neoplasm
- lymphoma
- sarcoma
Pathology is complex
Clinical features of SG Tumours
Major Gland
- lump in affected gland
- asymmetry
- duct obstruction
- pain
- Facial palsy if affect parotid gland
Minor/ IO
- junction of hard/soft palate
- upper lip/ cheek
- ulcerate late (malignant)
Diagnosis Techniques
Biopsy is essential
- Ultrasonic guided fine needles (FNA): may only give little tissue extracted which is not enough to diagnose
- core biopsy: gives more tissue, usually used for breast tissue
- incisional biopsy
Problems in diagnosis
- number of tumour types
- variation due to tissues originate from different stem cell lines
- not all tumours fit the classification
- Immunohistochemistry using dyes to differentiate tumours
- molecular markers used - key genomic alterations
What does NOS stands for in classification
NOS- not otherwise specified (not know what type of tumour it is)
Pleomorphic adenoma
- 75% of all salivary tumours
- most common in parotid
- slow growth
- Histological slides do not look the same between all pts
- varied histology - mixed tumour
*duct epithelium
*myoepithelial cells
*Myxoid and chondroid areas - capsule variable
Histology of Pleomorphic adenoma
Incomplete capsule on the surrounding
- Easy to remove on surgical
- But may have tissue left beyond the boundary and may have recurrence
- Need at least 5 years of follow up to make sure there is no reoccurrence
- May get more than one occurring in the area
Treatment of Pleomorphic adenoma
- wide local excision
Problem after excision of Pleomorphic adenoma
- recurrence due to being multifocal
- progression to carcinoma
- May be painless as its slow growing
- The longer it stays in the patient, the bigger then chances to be malignant
Warthin’s Tumour (adenolymphoma)
- 15% of SGT
- most in parotid
- majority are smokers
- occasionally multiple/ bilateral (10%)
- histology: cystic, distinctive epithelium, lymphoid tissue
- treated by excision
- Good connective tissue capsule
- Recurrence is low
Histology of Warthin’s Tumour
Salivary Gland Carcinomas
- < 1% of all malignancy
- 15% of ST
- higher in minor glands
- 2 main types
Adenoid Cystic Carcinoma
- 5%, more in minor glands
- varied patterns: cribriform (swiss cheese like), tubular, solid
- Difficult malignancy to irradiate
- Dull continuous type of pain
- Growing along the nerves and may reoccur; difficult to treat
- Pt often come back to control spread of malignancy
- local spread to nerves and bone
- late spread by metastasis, by blood to lung
Histology of Adenoid Cystic Carcinoma
Mucoepidermoid carcinoma
- 3-5%
- histology (2 cell types): squamous (epidermoid), glandular (mucous)
- grading/ differentation: cystic/ solid
- unpredictable
- lymphatic spread is rare
- Mucous component from jaw- odontogenic epithelium can see mucous cells, has the ability to change to mucous glands
Histology of Mucoepidermoid carcinoma
Alcian blue - to see mucous secreting cells clearly in slides
Grading of MEC
Acinic cell carcinoma
- rare
- most in parotid
- histology varied
Polymorphous adenocarcinoma
- minor glands in palate
- locally infiltrate (nerves)
- immunohistochemistry
