Sinonasal Disease

Question 1

Describe the ostiomeatal unit.

Answer 1

1. Maxillary cilia waft mucus superomedially to the maxillary ostium
2. Through the infundibulum
3. Then past the hiatus semilunaris (between the ethmoid bulla and uncinate process)
4. Draining in to the middle meatus

Question 2

What is the ostiomeatal pattern of compression?

Answer 2

Obstruction at the level of the hiatus semilunaris resulting in opacification of the ipsilateral maxillary sinus, anterior and middle ethmoid air cells, and frontal sinus.

Question 3

What is an antrochoanal polyp?

Answer 3

Solitary sinonasal polyp which arises within the maxillary sinus and passes through and enlarges the sinus ostium (widening of the maxillary ostium) and extends in to the nasopharynx.
Typically, there is no associated bony destruction.
Important to identify because if it is snared like a nasal polyp, it will recur because its antral stalk will still be there.

Question 4

What is an inverting papilloma?

Answer 4

A polypoid lesion that occurs on the lateral nasal wall, centred on the hiatus semilunaris with occasional extension into the antrum. Focal hyperostosis tends to occur at the tumour origin.
On CT, 40% of cases demonstrate intra-lesional calcification (“entrapped bone”).
On T2 and T1+gad sequences, it can demonstrate a convoluted cerebriform pattern.
There is a risk of malignant transformation (10%) to squamous cell carcinoma.

Question 5

What are juvenile nasopharyngeal angiofibromas?

Answer 5

A tumour arising from the fibrovascular stroma of the nasal wall adjacent to the sphenopalatine foramen. It can cause expansion of the pterygopalatine fossa.
Primary vascular supply is from the ascending pharyngeal artery and/or internal maxillary artery.
Enhances avidly and contains dark flow voids on T1.
Typically seen in male adolescents presenting with a nasal mass and epistaxis.

Question 6

What are some important features of sinonasal squamous cell carcinoma?

Answer 6

1. Maxillary antrum is involved in 80%
2. Associated with destruction of sinus walls
3. Low signal on T2 (highly cellular)
4. Enhances less than other sinus malignancies

Question 7

What are some of the features of sinonasal lymphoma?

Answer 7

1. Nasal cavity is affected more commonly than sinuses
2. Highly variable appearance
3. Homogenous mass with bony destruction
4. Low T2 signal (highly cellular)

Question 8

What is esthesioneuroblastoma?

Answer 8

A neuroblastoma of olfactory cells which is classically dumbbell shaped with its waist at the cribriform plate. Demonstrates avid and homogenous enhancement.

Question 9

Causes of epistaxis.

Answer 9

Most common location is the anterior septal area (Kiesselbach plexus) which is usually compressible.
Posteriorly (5%) is mainly supplied by the sphenopalatine artery (terminal internal maxillary artery) and is a target of embolisation.