Spark ImageWise 45

Muco-epidermoid variant of Ocular surface squamous neoplasia

Dr. Samyak Gupta, Dr. Prabhat Nangia, Dr. Sarang Lambat, Dr. Vinay Nangia 
559, Suraj Eye Institute, Nagpur.

Case Description
A male, 72 years of age, came with a complaint of redness and irritation in left eye since 3 years. He was a known case of Diabetes mellitus and Ulcerative colitis. His best corrected visual acuity(BCVA) was 6/9 P, N6 in right eye (OD) and 6/9, N6 in left eye (OS). Anterior segment examination showed immature cataract in the both eyes and left side showed a mass temporally adjacent to the limbus. Mass was fixed to the limbus from 4 to 5 ‘o’ clock and measured approximately 3 x 3 cm. Mass was mobile over conjunctiva and its surface was seen to stain with rose bengal. Feeder vessels were seen to supply the mass. Intraocular pressure recorded by Goldmann applanation tonometer was 24 mmHg in OD and 20 mmHg in OS. Fundus examination in both eyes was within normal limits.

Figure 1 A: Slit lamp photograph under diffuse illumination of the left eye showing a well defined, slightly elevated mass attached to the limbus (yellow arrow) with feeder vessels (white arrow).

Figure 1 B: Slit lamp photograph of the left eye under diffuse illumination and higher magnification  showing positive Rose bengal staining(yellow arrow) and feeder vessels (white arrows).
Figure 2: The anterior segment optical coherence tomography scan of left eye passing through the lesion showed hyperreflective region (green arrow), thickened epithelium (yellow arrow) and abrupt transition from normal to abnormal epithelial tissue (blue arrow) suggestive of Ocular surface squamous neoplasia.

Patient was diagnosed as a case of Ocular surface squamous neoplasia(OSSN). He was advised to undergo excision of the mass with cryotherapy. He underwent the procedure which was done with a no-touch technique and a 4 mm clear margin was removed. Amniotic membrane transplantation was done to cover the area of tissue defect created. Excised tissue was sent for histopathological analysis. Histopathological examination confirmed the lesion to be a OSSN of the mucoepidermoid variant.

Figure 3 A: Slit lamp examination at 3 days post-operatively of left eye under diffuse illumination showed amniotic membrane graft at the site of excised OSSN mass (yellow arrow).

Figure 3 B:
Slit lamp examination at 3 days post-operatively of left eye with cobalt-blue filter for illumination and Wratten No.12 Filter for examination showed positive staining with fluorescein of the Amniotic membrane graft with healing edges (red arrows).  
Figure 4 A: Histopathology photograph of H & E stained section of the lesion showing atypical squamous cells (yellow arrow) and presence of mucin (black arrow).

Figure 4 B:
Histopathology photograph of H & E stained section of the lesion under high magnification showing atypical squamous cells (yellow arrow) and mucin (black arrow).
Figure 5 A: Histopathology photograph of lesion showing postive tumour margins inferiorly (black arrow).

Figure 5 B:
Histopathology photograph of lesion showing postive tumour margins temporally (black arrow).

Due to presence of positive margins on histopathology and aggressive nature of the lesion, patient was referred to an oncologist. Subsequently patient underwent cycles of brachytherapy and was started on topical interferon α-2b (1 million IU/ml), 5 times/day. Further follow up visits throughout a year did not show any recurrence of the lesion.
Figure 6 A: Slit lamp examination at 1 month post-operatively of left eye under diffuse illumination showed amniotic membrane graft epithelisation (white arrow).

Figure 6 B:
Slit lamp examination at 1 month of left eye with cobalt-blue filter for illumination and Wratten No.12 Filter for examination showed healed defect (white arrow)
Figure 7: AS-OCT of left eye at 6 months postoperatively does not show any hyperreflective area, thickened epithelium or abrupt transition zones indicating the absence of  any recurrence of OSSN (yellow arrow).

Discussion

Ocular surface squamous neoplasia(OSSN) is a term coined to denote the  wide spectrum of dysplastic changes involving epithelium of conjunctiva,  cornea  and  limbus. 

OSSN has 3 grades viz. Benign dysplasia, pre-invasive OSSN and invasive OSSN. Risk factors include exposure to UV-B light and Human papilloma virus. Xeroderma pigmentosa and human immune-deficiency virus(HIV)  patients  develop OSSN  at  an  earlier  age. Muco-epidermoid OSSN is a very rare variant but is known to be significantly more aggressive than other variants.

Typical presentation of OSSN is of a slightly elevated lesion and has tufts of vessels known as sentinel vessels. Appearance of OSSN on anterior segment OCT is very typical characterized by hyperreflectivity, abrupt transition from normal to abnormal tissue and epithelial thickening. AS-OCT aids in differentiating OSSN from other benign lesions like pterygium and other epibulbar lesions. It also gives an exact extent of margins of the lesion and is also helpful in identifying recurrence post-operatively. 

Treatment options include topical chemotherapy with Mitomycin C or Interferon α-2b, tumour excision with cryotherapy and amniotic membrane transplantation. No touch technique during OSSN avoids direct manipulation of the tissue and prevents tumor seeding. Cryotherapy during surgery causes ischemic necrosis and destroys any residual tumor beyond the  surgical margin of excision, thereby reducing recurrence. Topical chemotherapy decreases the risk of limbal stem cell deficiency, and removes the need for clear tumor margins as it treats the entire ocular  surface, including the potentially dysplastic cells. Agents include Mitomycin C, 5-Fluorouracil, Interferon alpha2b and Pegylated interferon alpha2b.

In our case, patient had 1-2 clock hours of lesion with typical features of OSSN. Therefore we decided to do a local excision with no-touch technique and 4 mm clear margins. Intraoperative cryotherapy was done to the residual conjunctiva beyond excised margins. On histopathology, the lesion was confirmed to be OSSN of the muco-epidermoid variant and margins were noted to be positive for tumor cells. Prompt referral to an oncologist and initiation of topical interferon alpha2b post-operatively may have been instrumental in preventing any recurrence even after 6 months to 1 year of surgery. Amniotic membrane transplantation simultaneously during surgery was effective for reconstruction of tissue defect.

ReadWise 

  1. Mittal R, Rath S, Vemuganti GK. Ocular surface squamous neoplasia–Review of etio-pathogenesis and an update on clinico-pathological diagnosis. Saudi Journal of Ophthalmology. 2013 Jul 1;27(3):177-86.
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  2. Li AS, Shih CY, Rosen L, Steiner A, Milman T, Udell IJ. Recurrence of ocular surface squamous neoplasia treated with excisional biopsy and cryotherapy. American Journal of Ophthalmology. 2015 Aug 1;160(2):213-9.
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  3. Goktas SE, Katircioglu Y, Celik T, Ornek F. Surgical amniotic membrane transplantation after conjunctival and limbal tumor excision. Arquivos brasileiros de oftalmologia. 2017 Jul;80:242-6.
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Correspondence 

Dr Prabhat Nangia
DNB, FICO, FMRF, FAICO
Consultant  
Department of Cornea and Ocular Surface
Suraj eye Institute
Email – education@surajeye.org

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