Dr. Anamika Patel, Dr. Swathi Kaliki, Dr. Dilip Kumar Mishra
Lesions simulating ocular surface squamous neoplasia (OSSN) clinically: A histopathological analysis
Anamika Patel, M.D1
Swathi Kaliki, M.D.1
Dilip K Mishra, M.D.1
From 1The Operation Eyesight Universal Institute for Eye Cancer (AP, SK, DM), L V Prasad Eye Institute, Hyderabad, India.
Support provided by The Operation Eyesight Universal Institute for Eye Cancer (SK) and Hyderabad Eye Research Foundation (SK), Hyderabad, India.
No conflicting relationship exists for any author.
Inquires to:
Swathi Kaliki, M.D., The Operation Eyesight Universal Institute for Eye Cancer, L V Prasad Eye Institute, Hyderabad-500034
Email: kalikiswathi@yahoo.com
Tel: 91 40 30612502 Fax: 91 40 23548339
Acknowledgement:
We acknowledge the help of George Ramappa, B.Com. for assistance in data collection.
Keywords:
Eye
Ocular surface Squamous Neoplasia
Pterygium
Actinic Keratosis
Pseudoepitheliomatous Hyperplasia
Abstract
AIM:
To describe lesions simulating OSSN clinically and discuss their histopathological diagnosis.
METHODS:
Retrospective study
RESULTS:
One hundred and ninety five patients with clinical diagnosis of OSSN were included in the study. The average age at diagnosis was 42 years. There was male preponderance (n=133, 68%). Most common presenting complaint was presence of mass lesion (n=56, 29%). Average duration of symptoms was 10 months. The most common location of tumor was in the nasal bulbar conjunctiva (n=74, 38%). The final diagnosis was established by excision biopsy (n=175,90%) or incision biopsy (n=20,10%). On histopathology, the most common diagnosis included actinic keratosis (n=53, 27%), chronic inflammation (n=41, 21%) pseudoepitheliomatous hyperplasia (n=18, 9%), pterygium (n= 10, 5%), and pyogenic granuloma (n=8, 4%).
CONCLUSIONS:
In our study, the most common misdiagnosis for OSSN included actinic keratosis, chronic inflammation, and pseudoepitheliomatous hyperplasia.
Ocular surface squamous Neoplasia (OSSN) term coined by Lee and Hirst, shelters dysplastic and carcinomatous lesions of the ocular surface. (1) Common risk factors known are UV rays, smoking, immunosuppression, Vitamin A deficiency, Human Papillomatous Virus 16 and XerodermaPigmentosa. Incidence rate being 0.13 to 1.9 cases per 100,000 people per year. It is a third most common ocular tumor after melanoma and Lymphoma. Clinically it manifests as elevated conjunctival or corneal lesion with associated keratin, feeder vessels, and intrinsic vascularity. Lesions similar to OSSN have been reported in the past namely Pterygium ,pingueculae, chronic conjunctivitis, pyogenic granuloma and squamous papilloma.(2) OSSN is the most common finding in ocular tumor surface biopsies (53%)(3)and hence can be easily confused with various simulating lesions.
Our study aims to describe various lesions that mimic lesions of OSSN on clinical presentation and how the histopathology determined the final diagnosis.
Methods
We conducted a retrospective study of all the pathology records of the Ocular Pathology services of LV Prasad Eye Institute and searched for cases where clinical diagnosis of ocular surface squamous neoplasia was made. We found a total number of one ninety-five patients with clinical diagnosis of OSSN.Upon reviewing the histopathology diagnosis various entities like Actinic Keratosis, Chronic inflammation, Pseudoepitheliomatous hyperplasia and Pterygium were encountered as final histopathological diagnosis against the clinical diagnosis of OSSN.
Different surgeons did surgical approach by excision and incision biopsy. Few cases underwent Map biopsy.
A single experienced ocular pathologist of our institute examined all the lesions. Demographic information recorded from the pathology report included sex and age; involved eye, location and extent of lesion. Treatment information, including modes of surgical technique were recorded.Only cases with clinical diagnosis of Ocular Surface Squamous Neoplasia were included for the study.
Results
The average age at diagnosis was 42 years. Male (n=133, 68%) and female (n= 62, 32%) were involved, male being affected more. Most common presenting complaint was presence of mass lesion (n=56, 29%) among other complaints like redness, pain, watering and diminution of vision. Average duration of symptoms was 10 months. The most common location of tumor was in the nasal bulbar conjunctiva (n=74, 38%) followed by inferior, temporal and superior bulbar conjunctiva. The final diagnosis was established by excision biopsy(n=175,90%) or incision biopsy( n=20,10%).
On histopathology, the most common diagnosis included actinic keratosis (n=53, 27%), chronic inflammation (n=41, 21%) pseudoepitheliomatous hyperplasia (n=18, 9%), pterygium (n= 10, 5%), and pyogenic granuloma (n=8, 4%).
Discussion
The conjunctiva is composed of epithelium and stroma. The epithelium consists of both stratified squamous and columnar epithelium. (4) The squamous pattern is found near the limbus and the columnar pattern is found near the fornix. The stroma is composed of fibrovascular connective tissue that thickens in the fornix and thins at the limbus. Neoplasms can arise in the conjunctiva from both its epithelial and stromal structures.(5)
Ocular surface squamous neoplasia has a varied range of presentation from mild dysplasia to invasive squamous cell carcinoma. Classically it is characterized by elevated conjunctival or corneal lesion with associated keratin, feeder vessels and intrinsic vascularity. Thus can easily be confused with various lesions simulating as OSSN.(6)
Conjunctivalpseudoepitheliomatous hyperplasia is a benign reactive inflammatory proliferation of the epithelial cells, which simulates carcinoma both clinically and histopathologically. Clinically it manifests as an elevated leukoplakic pinkish lesion in the limbal area and histopathologically as massive acanthosis, hyperkeratosis, and parakeratosis of the conjunctival epithelium. There by difficulty persists in clinical and histological differentiation of the lesion from low-grade SCC. (7)In our study 18 cases of Pseudoepitheliomatous Hyperplasia were misdiagnosed as Ocular surface squamous neoplsia where in only one case of LimbalPseudoepitheliomatousHyerplasia mimicking as OSSN has been reported so far by Malhotra C et al.(8)
There are several benign and malignant lesions that arise from squamous epithelium of conjunctiva. Actinic Keratosis is a type of lesion that generally develops in inter palpebral conjunctiva. It often has a frothy appearance and looks very similar to conjunctival intra epithelial neoplasia which has a higher chance of conversion to invasive squamous cell carcinoma. (7) In our study Actinic Keratosis was seen in 27% of all the cases.
Pyogenic granulomas are vasoproliferative inflammatory lesions composed of granulation tissue, and commonly occur on the cutaneous or mucosal surfaces. They usually follow trauma or infection and may mimic as OSSN.(9) In our study 4% pyogenic granuloma were misdiagnosed as ocular surface squamous neoplasia.
Pterygium has its own long association with ocular surface squamous neoplasia and has been studied widely in the past. Hirst et al in 2009 reported rate of ocular surface squamous neoplasia as 9.8% in their study of sequential pterygium specimens where clinical diagnosis of squamous neoplasia was not suspected. (10) In our study we found 5% cases of pterygium suspected as squamous neoplsia.
Chronic inflammation simulating as OSSN has not been reported so far, which accounted for 21% in our study.
Serial Photographic documentation and Anterior Segment Ocular Coherence Tomography are the best bait in situations like these where we come across lesions that mimics as ocular surface squamous neoplasia. Standard Ocular Coherence Tomography and Ultra high resolution Ocular Coherence Tomography helps in delineating the abrupt transitions from normal to abnormal epithelium as studied by Shoushaet al. (11)
Recently group of Hang et al. reviewed the applications of anterior segment ocular coherence tomography and concluded their major role in ocular surface disorders. (12)
Conclusion
Although Histopathology is the only infallible method for conclusive diagnosis for Ocular surface squamous neoplasia, close observation and anterior segment tomography may also help in lesions mimicking ocular surface squamous neoplasia.
To the best of our knowledge such large data of lesions mimicking Ocular surface squamous neoplasia has not been studied so far and thereby aids in the clinical judgment of lesions mimicking surface neoplasia and their appropriate management.
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