Ocular Surface Squamous Neoplasia

Call Now (03) 343-6033

On this page… What is ocular surface squamous neoplasia? | How is it diagnosed? | Medical Treatment | Surgical Treatment | FAQs and Links ↓

What is it?

Ocular surface squamous neoplasia

Ocular surface squamous neoplasia

Ocular surface squamous neoplasia (OSSN) is a common malignancy of the conjunctiva and cornea. It can be thought of as a “skin cancer” of the eye.

Clinical features

Typical features of OSSN include:

  • Arises near the limbus (junction of cornea and sclera)
  • Most commonly found at the 3 or 9 o’clock position
  • Fleshy, gelatinous appearance
  • Round or oval shape
  • Irregular blood vessel pattern
  • Minimal symptoms
  • Slow growing

Who gets OSSN?

OSSN is more common in patients who are:

  • Older
  • Have had significant sunlight exposure
  • Are taking immune system supressing drugs

Differences between OSSN and pterygia

OSSN can mimic a pterygium. In general pterygia:

  • Occur at a younger age
  • Are more triangular in shape
  • Appear flatter rather than gelatinous
  • Have more linear blood vessels
  • Cause more symptoms

Top ↑

How is it diagnosed?

Ocular surface squamous neoplasia

Ocular surface squamous neoplasia

Some OSSN are first noticed by patients and their friends. In most cases the diagnosis is made by an optometrist or ophthalmologist.

Unusual looking pterygia and definite cases of OSSN are referred to eye specialists for examination with the slit lamp microscope.

OSSN may look very like a pterygium and in some cases only surgical removal and examination of the abnormal tissue by a pathologist will confirm the diagnosis.

Top ↑

Medical treatment

Some OSSN can be treated by chemotherapy with Mitomycin C eyedrops.

OSSN prior to treatment with Mitomycin C - see below for results of treatment

OSSN prior to treatment with Mitomycin C – see below for results of treatment

Mitomycin C (MMC)

MMC is a drug used to treat some types of cancer and to reduce scarring after surgery. It is regularly used in a number of eye conditions including glaucoma surgery. MMC has been used to treat OSSN for the last decade.

MMC in OSSN

MMC is used to treat OSSN when:

  • Patients decline surgery
  • Tumours are small
  • Surgery was unsuccessful in removing all the tumour
  • The tumour is aggressive or invasive
  • Surgical removal of a large tumour would threaten the viability of the eye

Treatment with MMC

Same eye as above, following successful treatment of OSSN with Mitomycin C

Same eye as above, following successful treatment of OSSN with Mitomycin C

Same eye as above, following successful treatment of OSSN with Mitomycin C.

Patients with suspected or confirmed OSSN typically receive a course of treatment:

  • Four times a day
  • Week on, week off cycles
  • For two to four cycles

Risks of MMC

The risks of MMC therapy are very low but include:

  • Failure to achieve eradication of the tumour
  • Irritation of the surface of the eye

Top ↑

Surgical Treatment

OSSN spreading around the limbus

OSSN spreading around the limbus

The traditional treatment of OSSN is surgery.

Indications for surgery

Some patients are best treated by surgical excision. This includes those with:

  • Large tumours
  • An uncertain diagnosis

Surgery for OSSN

Removal of OSSN is usually performed under local anaesthesia. Traditionally at the time of surgery the surrounding area was frozen or painted with alcohol to eradicate any residual tumour cells. Now the tumour is simply excised and follow up treatment with Mitomycin C is arranged if the diagnosis is confirmed by a pathologist.

Top ↑

FAQs and Links

What causes OSSN?
The most common cause is ultraviolet light.

Can it cause blindness?
Yes, but only if left untreated.

Can it spread to other parts of the eye and body?
Spread is extremely rare.

Recommended links

Ocular surface squamous neoplasia →

Top ↑