Salivary gland

Question 1

Well circumscribed salivary tumour, composed of cysts and papillae lined by a double layer (inner columnar and outer cuboidal) of oncocytic cells, surrounded by a lymphoid stroma including germinal centres.

Answer 1

Warthin’s tumour

Plan:
Correlate with clinical history and radiology (?pre-operative FNA)
Examine further sections (e.g. for total size, relation to margins)
IPX: Not required for diagnosis

Question 2

Well circumscribed and often encapsulated salivary tumour. Composed of epithelial cells (forming ducts), surrounding myoepithelial cells, and stroma. Stroma is typically myxoid/chondroid. Myoepithelial cells tend to meld into the stroma. Individual cells are cytologically bland, with small, oval, pale nuclei.

Answer 2

Pleomorphic adenoma

Plan:
Correlate with clinical history and radiology (?pre-operative FNA ?suspicion of carcinoma ex pleomorphic adenoma)
Examine further blocks (e.g. for total size, relation to margins, evidence of carcinoma ex pleomorphic adenoma)
IPX: Not required for diagnosis. If available, PLAG1, HMGA2
Next steps: Synoptic report

Question 3

Well circumscribed salivary tumour. Partly cystic, and composed of three cell types: epidermoid (squamous) cells, mucocytes, and intermediate cells (smaller and less differentiated than fully developed mucous or epidermoid cells).

Answer 3

Mucoepidermoid carcinoma (low grade)

Differential diagnosis:
Necrotising sialometaplasia

Plan:
Correlate with clinical history and radiology (?pre-operative FNA)
Examine further blocks (e.g. for total size, relation to margins, areas of differing morphology)
Molecular: FISH for MAML2 rearrangement
Next steps: Synoptic report, discuss at MDT

Question 4

Highly infiltrative oral cavity tumour with perineural invasion. Predominant myoepithelial cells impart a basaloid appearance. Growth pattern can be tubular, cribriform, or solid. Tumour cells are surrounded by hyalnized reduplicated basement membrane material.

Answer 4

Adenoid cystic carcinoma

Plan:
Correlate with clinical history and radiology
Examine further blocks (e.g. for total size, relation to margins, perineural invasion, areas of solid growth etc)
IPX to support Dx: cKIT, MYB (expect positive)
Next steps: Synoptic report, discuss at MDT

Question 5

Circumscribed and encapsulated salivary gland tumour, composed of nests and sheets of oncocytes, with uniform centrally placed round nuclei with vesicular chromatin and a single prominent nucleolus.

Answer 5

Oncocytoma

Differential diagnosis:
Acinic cell carcinoma
Metastatic renal carcinoma

Plan:
Correlate with clinical history and radiology (?pre-operative FNA)
Examine further blocks (e.g. for total size, relation to margins)
IPX to support Dx: p63 (highlight basal cells)
IPX to discount DDx: DOG1, SOX10, PAX8
No further action required for this benign diagnosis

Question 6

Salivary gland with a simple unilocular cyst with a thin stratified squamous lining surrounded by normal lymphoid tissue

Answer 6

Lymphoepithelial cyst

Plan:
Correlate with clinical history and radiology (?HIV ?Sjogren syndrome ?pre-operative FNA)
No specific further action required for this benign diagnosis.