aCase 11

by Dr.Chua

A 43-year-old secretary presented with swelling of her right face and nasal discharge two weeks after a dental extraction. She was referred to the otolaryngologist for a suspected maxillary sinus abscess. Examination revealed swelling of the face over the cheek with deviation of the left nostril. The left eye was proptosed with superior displacement of the globe. Her right vision was 6/9 and there was no afferent pupillary defect. An urgent scan showed a mass lesion arising from the maxillary sinus. The lesion eroded through the hard palate, orbital floor and the medial wall into the orbit and extended as far as the extradural space in the anterior cranial fossa. Biopsy showed squamous cell carcinoma. The patient was informed of the diagnosis and given the choice of radical surgery followed by radiotherapy or just radiotherapy. Radical surgery was decided upon. Before the surgery, the patient's vision was noted to have declined to 6/60 with an afferent pupillary defect.

The patient underwent total right maxillectomy, right exenteration and exploration and excision of tumour from the anterior cranial fossa. Cervical lymph nodes were also biopsied for any presence of metastasis. A free flap from her thigh was taken by the plastic surgeon to cover the facial defect. The right upper palate was covered with a dental obturator.

Figure 1. CT scans showing a destructive lesion extending from the maxillary sinus into

the orbit, ethmoid sinus and the extradural space of the anterior cranial fossa.

a. How common is maxillary sinus carcinoma?

Malignant tumors of the sinuses make up < 1% of all malignancies in the body and about 3% of head and neck cancers. The incidence is about 1:100,000 people per year. The maxillary sinus is the most common site (55%) for sinus tumour followed by the ethmoid sinus (9%). Sphenoid sinus is rarely involved.

Sinus malignancy is associated with certain occupation. Nickel workers is 100 X more likely than normal population to suffer from sinus squamous cell carcinoma. Leather workers and furniture makers are at risk of adenocarcinoma.

b. How does maxillary sinus tumour spread to the anterior fossa?

Maxillary sinus tumour spreads to the anterior fossa via the ethmoids or orbit or both. The usual area of penetration is either through the narrow common wall it shares with ethmoid at the medial roof of the maxillary sinus or through the superior aspect of the medial wall of the maxillary ascent into the bulla ethmoidalis. Medial extension brings them into the the nasal cavity and growth in the rostral direction results in encroachment on the cribriform plate.

Figure 2. Exenterated right eye on the left (M= medial aspect) and

total right maxillectomy (arrow points to the tumours in white)

Figure 3. Exenterated eye showing tumours (arrowed) on the medial and

inferior aspects ( S = superior; M = Medial and ON = optic nerve).

c. What is the ohngren's line?

Ohngren's line is the theoretical plane joining medial canthus of the eye with the angle of the mandible. This line divides the maxilla into the infrastructure and superstructure. It was originally described by Dr. Ohngren in 1930 to delineate the limits of resectability of a tumor in the maxillary sinus. Tumors superoposterior to Ohngren's line were more likely to involve the orbit, ethmoids, and pterygopalatine fossa.

Figure 4. Ohngren's line (red)

Malignancy behind Ohngren's line is regarded to carry a much poorer prognosis because of the rapid spread to the orbit and middle cranial fossae. The access to the middle fossa is by virture of the proximity of the lateral wall of the optic canal, as well as the posterolateral orbital wall to the anteriormost extension of the temporal lobe.

d. What is the main disadvantage of covering the cheek and exenterated orbit with a free flap?

Using a free flap to cover the resulting defect offer protection against infection and psychological trauma for the patient and family. It has the potential disadvantage of prevent easy observation of the primary tumour site and early recurrence may not be detected. However, this is thought to be of little clinical significance as tumour recurrence following such radical surgery and radiotherapy is usually untreatable. 

Reference:

1. Donald PJ, Gluckman JL, Rice DH. The sinuses. 1995 Raven Press.

2. Jafek BW, Stark AK. ENT secrets. 1997 BPS Publications.