Other head and neck

Question 1

Oral tumour with islands / cords set within fibrous stroma with hyperchromatic peripherally palisaded cells (with reverse polarity and subnuclear vacuoles) and central regions resembling stellate reticulum.

Answer 1

Ameloblastoma

Plan:
Correlate with clinical history and radiology (?mandible lesion)
Examine further blocks (e.g. for total size, relation to margins, areas of differing morphology)
IPX to support Dx: CK5, CK19, BRAF V600E
Next steps: Synoptic report, discuss at MDT

Question 2

Nasal polyp with fibrous stroma rich in bland spindle cells and vascular spaces of various sizes

Answer 2

Juvenile nasopharyngeal angiofibroma

Differential diagnosis:
Haemangioma
Normal nasal turbinate

Plan:
Correlate with clinical history and radiology (?pre-operative angiography)
IPX to support Dx: AR, beta catenin (positive in stromal cells, nuclear beta catenin positivity)
No specific further action required for this benign diagnosis

Question 3

Head/neck tumour with poorly differentiated malignant epithelial cells with syncytial growth, admixed with a prominent lymphocytic infiltrate. Cells have vesicular nuclei with macronucleoli.

Answer 3

Naropharyngeal carcinoma

Differential diagnosis:
DLBCL
Non-keratinsing (e.g HPV related) SCC
Melanoma
Rhabdomyosarcoma
Other poorly differentiated carcinomas (sinonasal undifferentiated carcinoma, NUT carcinoma, SWI/SNF deficient carcinoma)

Plan:
Correlate with clinical history (?patient from endemic area)
Examine further blocks
IPX to support Dx: AE1/AE3, p40, EBER ISH (expect positive)
IPX to discount DDx: CD45 and CD20, p16, S100 and SOX10 and Melan A, desmin and myogenin, NUT, SMARC proteins
Molecular: NGS for IDH mutation if suspect SNUC after IPX
Next steps: Synoptic report, discuss at MDT

Question 4

Oral cyst with fibrous cyst wall with flat non-keratinising squamous epithelium 2 - 4 layers thick

Answer 4

Dentigerous cyst

DDx
Periapical cyst (if inflamed)

Plan:
Correlate with clinical history and radiology (?assiociated with crown of unerupted tooth)
IPX: Not required for diagnosis
No specific further action required for this benign diagnosis

Question 5

Oral cyst with fibrous cyst wall with stratified squamous lining with flat palisaded basal layer (lacking rete ridges) and surface with corrugated parakeratosis

Answer 5

Odontogenic keratocyst

Plan:
Correlate with clinical history and radiology
No specific IPX or molecular available
Advice to clinician: Locally aggressive, may recur if incompletely excised

Question 6

Small blue round cell tumor of head/neck with lobulated growth pattern and abundant neuropil. Homer Wright pseudorosettes and Flexner-Wintersteiner (true) rosettes may be seen

Answer 6

Olfactory neuroblastoma

DDx
Sarcomas: Ewing’s, Rhabdomyosarcoma
Lymphoma
Melanoma
Poorly differentiated carcinoma: Small cell neuroendocrine, sinonasal undifferentiated carcinoma, NUT carcinoma, SWI/SNF deficient carcinoma

Plan:
Correlate with clinical history and radiology (?cribriform plate tumour)
Examine further blocks
IPX to support Dx: Synaptophysin, chromogranin, neurofilament (expect positive)
IPX to discount DDx: CD99 and FLI1, desmin and myogenin, CD45, SOX10 and Melan A, AE1/AE3 and CAM5.2
Next steps: Hyams grade, Kadish stage, synoptic report, discuss at MDT

Question 7

Oral cavity tumour made of large cells with abundant fibrillar eosinophilic cytoplasm with cross striations, without nuclear atypia

Answer 7

Adult type rhabdomyoma

Differential diagnosis:
Granular cell tumour
Oncocytoma

Plan:
Correlate with clinical history and radiology
Examine further blocks (e.g. for size, relation to margins, areas of differing morphology)
IPX to support Dx: Myogenin, MyoD1
IPX to discount DDx: CD68, S100, AE1/AE3
No specific action required for this benign diagnosis

Question 8

Cystic eyelid lesion lined by inner layer of columnar cells with apocrine snouts, and an outer layer of flattened myoepithelial cells. Papillary projections of the lining epithelium into the cyst lumen may also be observed. The cyst lumen contains amorphous eosinophilic material.

Answer 8

Apocrine hidrocystoma

Plan:
Benign diagnosis - no specific further action required.

Question 9

Neck cyst in young adule with stratified squamous epithelium lining and fibrotic wall with lymphoid follicles resembling lymph node or tonsil

Answer 9

Branchial cleft cyst

Plan:
Correlate with clinical history and radiology
No specific action required for this benign diagnosis

Question 10

Ear lesion with biphasic epithelial/myoepithelial population of cells forming glandular, papillary, and cystic structures within a hyalinised fibrous stroma. The inner luminal cells are cuboidal to columnar with eosinophilic cytoplasm and may contain yellow-brown pigment and show apical snouts.

Answer 10

Ceruminous adenoma

Differential diagnosis
Middle ear adenoma (neuroendocrine tumour)

Plan
Correlate with clinical history and radiology
IPX to discount Ddx: Synaptophysin, chromogranin
No specific action required for this benign diagnosis

Question 11

Nasal lesion with endophytic growth of interconnecting epithelial nests with smooth outer contours; epithelium may be squamous, respiratory, or transitional

Answer 11

Inverted (Schneiderian) sinonasal papilloma

Plan
Correlate with clinical history and intraoperative findings (?known HPV)
Examine further blocks (for any associated malignant transformation)
IPX to support Dx: ISH for high and low risk HPV