[1] Ocular Surface Squamous Neoplasia (OSSN) refers to a spectrum of dysplastic and malignant squamous lesions of the conjunctiva and cornea. [2] Diagnosis is usually clinical but can be confirmed with biopsy. For suspected OSSN less than 3 clock hours, excision biopsy with cryotherapy and alcohol epitheliectomy is performed. Larger lesions may require chemoreduction with topical chemotherapy prior to surgery and cryotherapy. [3] Risk factors include ultraviolet light, HIV, and human papillomavirus. While rare, metastasis can occur to local lymph nodes or distant sites like lungs. Recurrence after treatment ranges from 15-52% depending

1. OCULAR SURFACE
SQUAMOUS NEOPLASIA(OSSN)
Dr. (Maj.) A.K.M Rashed-Ul-Hasan
FCPS-ll student
National institute of ophthalmology & Hospital
Dhaka

3.  OCULAR SURFACE denotes involvement
of the conjunctiva or cornea
 SQUAMOUS excludes other epithelial
cells such as basal cells and melanocytes
 NEOPLASIA includes both dysplastic and
carcinomatous lesions.

4. Definition
The term Ocular Surface Squamous
Neoplasia [OSSN] presently refers to the
entire spectrum of dysplastic, pre-invasive
and malignant squamous lesions of the
conjunctiva and cornea

5. Lee and Hirst classified OSSN as:-
I. BENIGN DYSPLASIA
• Pseudoepitheliomatous hyperplasia
• Benign hereditary intraepithelial dyskeratosis
II. PREINVASIVE OSSN
• Conjunctival/corneal carcinoma in situ
III. INVASIVE OSSN
• Squamous carcinoma
• Mucoepidermoid carcinoma – aggressive

6. Epidemiology
 Third most common ocular tumour after melanoma
and lymphoma
 Caucasians
 older age group(6-7 decade)
 Males >females
 Patiens with HIV and Xeroderma pigmentosum
present earlier
All young patients with OSSN should be screened for
HIV.

7. Risk factors
 Ultraviolet light
 Immunosuppression/ HIV
 Human papillomavirus (HPV)- Type 16 & 18
 Mutation or deletions of tumor suppressor
gene p53

8. Clinical Features
 Patients may be asymptomatic or present with
chronic redness and irritation of the eye.
 Visual acuity is not affected unless there is
extensive corneal involvement
 In most cases, patient has the history of
several months.

9. Location
 OSSN normally occurs in
Interpalpebral region arising from the
limbal stem cells, involving the bulbar
conjunctiva, the cornea or both of these
structures

10. Clinically :
 The lesions are described as being
slightly elevated, variably shaped,
relatively sharply demarcated from the
surrounding normal tissues.
 Accompanied by feeder blood vessels
 Color vary from pearly gray to reddish
gray depending on the vascularity of the
tumor .

11. Gelatinous lesion Leukoplakic lesion
Papillomatous lesion
Corneal intra-epithelial
neoplasia
Appearance

12. In clinical practice, gelatinous type
is the commonest. These lesion can be
Circumscribed, which are most common
Nodular variety, which has a propensity
for rapid growth
Diffuse variety, the least common,
which can masquerade as chronic
conjunctivitis

13. Diagnostic Tests
Diagnosis is most often made clinically.
Fluorescein or Rose Bengal are often used to
highlight & delineating the extent the lesion.
Rose bengal stain of corneal epithelial dysplasia

14. a. Anterior Segment Optical Coherence
Tomography (ASOCT)
b. Impression cytology
c. Confocal microscopy
d. High frequency ultrasound
e. Histopathology
Diagnostic Tests

15. a. Anterior Segment Optical Coherence Tomography
(ASOCT) :
Distinctive features of OSSN
 hyper reflectivity
 thickened epithelium
 abrupt transition from normal to abnormal tissue

16. b.Cytology

17. c.Confocal microscopy
- helpful in guiding treatment since it is able
to reveal cellular details.
- difficulte of use and limited field of view

18. d. Histopathology
DYSPLASIA:
 Mild - less than a third thickness occupied by
atypical cells
 Moderate - three quarters thickness occupied
by atypical cells
 Severe - nearly full thickness occupied by
atypical cells

19. d. Histopathology
CARCINOMA IN SITU: as above with loss of the
normal surface layer
INVASIVE SQUAMOUS CELL CARCINOMA: as above
with basal epithelial layer has been breached and
invasion of the substantia propria has occurred.

20. d. Histopathology

21. d. Histopathology
Mild dysplasia Severe dysplasia
Carcinoma in situ Invasive SCC

22. e) High frequency ultrasound
 extent of invasion into the eye in cases of SCC.

23. Differential Diagnosis
 Pterygium
 Papilloma
 Pingueculum
 Nevus
 Malignant melanoma
 Pyogenic granuloma

24. Pterygium can be differentiated by
 younger age
 more triangular in shape
 flatter rather than gelatinous
 more linear blood vessels
 Cause more symptoms

25. Papilloma may occur
 younger patients
 anywhere on the conjunctiva
 may be sessile or pedunculated
 has a punctate vascular pattern
Pedunculated exophytic
conjunctival papilloma

26. Malignant melanoma has a
 regular smooth surface,
 lacks gelatinous or leukoplakic surface
 may be ulcerated

27. Benign nevi
younger patients
interpalpebral zone, from the limbus to the
caruncle
distinctive cysts on slit-lamp examination

28. Surgery
Chemotheraphy
Cryotheraphy
Radiotheraphy
Treatment

29. Surgical excision

32. Topical Chemotherapy

33. MITOMYCIN C
 Most commonly used
 A non cell cycle specific ALKYLATING AGENT
that acts by alkylating the cross-linked DNA
and inhibits DNA, RNA, and protein synthesis
 0.04% four times a day for 1 week with two to
three cycles in alternate weeks
 Success rates ranging from 87 to 100% have
been reported.

35. 5-FU
 Pyrimidine analogue that acts by
integrating with the DNA during S phase.
It also interferes with RNA synthesis.
 It is used as 1% topical solution four times
a day for 1 week , followed by 30 days or
1–2 weeks off
 Side effects are similar to MMC

36. Interferons
 For OSSN: Topical IFN- α2b.
 1 million IU/ml as 4 times a day until
resolution, and a month thereafter
 More expensive than MMC and 5 FU
 Requires prolonged treatment but has a
better safety profile

37. Radiotherapy
Plaque brachytherapy
Radiation sources like Strontium 90,
Rhuthenium 106 or I-125
Complications
Conjunctival scarring
Symblepharon
Dry eye
Cataract
Scleral & Corneal ulceration.

38. SUMMARY
[1] Suspected OSSN < 3 clock hours
Excision biopsy +
base/ edge cryotherapy +
alchohol epitheliectomy is done.

39. [2] Suspected OSSN 3 – 6 clock hours –
 A diagnostic biopsy is required
 Pre-invasive lesions
topical chemotherapy
 Invasive lesions
surgery + cryotherapy is done after
chemoreduction with 4 to 6 cycles of topical
chemotherapy.

40. [3] OSSN > 6 clock hours –
A diagnostic biopsy is
required.
 Pre-invasive lesions
Topical chemotherapy
 Invasive
Surgery + cryotherapy is done after
chemoreduction with 4 to 6 cycles of topical
chemotherapy.
 If there is no response to chemotherapy
Palliative radiotherapy or extensive surgery like
enucleation / exenteration may be required.

41. Metastasis
Regional and systemic metastases are also
uncommon.
Common sites of metastasis include pre-
auricular , submandibular and cervical lymph
nodes, parotid gland, lungs, and bone.

42. Recurrence
 Ranges from 15-52%, average 30%
 Higher in case of inadequate excision margins
 More aggressive behaviour

43. Conclusion
 Good clinical exam is sufficient for diagnosis.
 Excision with cryotheraphy is successful but
can be associated with recurrence rates
 Chemotherapeutic agents are usefull
alternative specially in recurrent, corneal &
annular lesion.