CASE REPORTS

Favourable outcome of giant malignant melanoma of the conjunctiva despite poor prognostic features

Kishan Pal Singh Malik, MS, MNAMS, FICS; Subhash Dadeya, MD; Braham Prakash Gulliani, MS; Vishnu Swaroop Gupta, MS

M alignant melanoma of the conjunctiva is uncommon but among the most serious ocular

malignant tumours. 1 Conjunctival melanomas more than 2 mm in diameter are usually at high risk of lethal metastasis. Features indicating a poor prognosis include greater age, location at the caruncle with involvement of the palpebral conjunctiva, tumour thickness greater than 1.5 mm, eyelid pigmentation, vertical growth and epitheloid cell type.2- 5 Giant malignant melanoma of the conjunctiva without metastases and with normal visual acuity has been reported only once. 6 We describe the presentation and management of a case of giant conjunctival malignant melanoma with a favourable outcome despite poor prognostic features.

CASE REPORT

A 70-year-old man from a rural area presented to us with a painless mass protruding through the lids of the left eye that had been progressively enlarging for 2 years. For the past 6 to 8 months the mass had involved about 80% of the palpebral aperture, occlud­ing the view of other structures. There was no history of trauma or of ocular surgery. The patient had con­tacted many ophthalmologists, who had expressed

From the Department of Ophthalmology. Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India

Originally received July 23, 2002 Accepted for publication Apr. 2, 2003

Reprint requests to: Dr. Subhash Dadeya, Assistant Professor, Guru Nanak Eye Center, Delhi-2, India; fax 91-11-23230033; dadeya86@hot­mail.com

This article has been peer-reviewed.

Can j Ophthalmol 2003;38:397-400

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their inability to treat the lesion because of its size and because the patient refused exenteration.

We admitted the patient to our hospital for investi­gation and management. We found a brownish-black, nonvascularized conical mass 30 X 20 mm in vertical and horizontal diameter that extended nasally to the caruncle and involved the bulbar and palpebral conjunctiva. There was no crust or induration of the margins. The mass was firm and nontender. The sur­rounding conjunctiva was chemosed (Fig. 1). We could not view the eye structures because of the mas­sive size of the mass. However, we confirmed that the tumour was arising from the limbus. Ultrasonography and computed tomography showed no intracranial extension. Physical examination of other systems, including the lymph nodes, and systemic investiga­tions such as liver function tests and chest radiogra­phy revealed no abnormalities. The right eye was essentially normal.

The tumour was excised in toto from its attach­ments and the conjunctiva repaired. Histopathological examination showed multiple round to spindle-shaped

Fig. 1-Giant malignant melanoma of the conjunctiva, occlud­ing more than 80% of the palpebral aperture.

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cells laden with brownish-black pigment (melanin); the ratio of nucleus to cytoplasm was high, and the nucleoli were prominent (Fig. 2). Malignant melanoma of the conjunctiva was diagnosed on the basis of the histopathological findings. After the histopathology report was received, cryotherapy was applied by the triple freeze-thaw technique to the areas of origin of the tumour.

After excision and cryotherapy, the patient's visual acuity was 6/9 and the fundus appeared normal. The only abnormality we could find was pterygium and the presence of nevi on the caruncle, conjunctiva and lower lid (Fig. 3). The patient was advised to have a follow-up evaluation every 3 months for evidence of recurrence. Eighteen months later the patient was happy. There was no evidence of recurrent tumour or metastasis.

Fig. 2-Excised tumour, showing melanoma cells, found underneath squamous epithelium (hematoxylin-eosin; original magnification X I 00).

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Fig. 3-Excellent cosmetic appearance postoperatively.

COMMENTS

Conjunctival melanoma is a potentially life-threat­ening tumour involving the mucosa of the eye and eyelids. Several attempts have been made to identify prognostic factors. Such identification is important for tumour classification in individual cases and for the choice of treatment.7•8 Jakobiec and colleagues3

claimed that tumour thickness is the "sovereign prog­nostic factor," but other authors have suggested that location, extension, multifocality and mitotic rate may influence the outcome.2•5 Melanomas involving the palpebral conjunctiva, the fornix and the caruncle are associated with a higher rate of metastasis, especially if they are multifocal.2•9•10 Multifocal melanomas have a worse outcome than unifocal tumours. 11

Conjunctival melanomas that grow vertically rather than horizontally fare worse.5 A melanoma of epithe­lioid or mixed-cell type has a greater risk of metasta­sis than a spindle-cell melanoma. Conjunctival malig­nant melanoma has a good prognosis in spite of its high rate of recurrence, because it is easy to find and it grows locally. 12 However, even superficially locat­ed malignant melanoma of the conjunctiva is believed to have a high potential for lymphatic metastasis.9•13, l4

Moreover, metastases in the liver, lung and brain have been reported. 14 Most of the metastases are initially detected in facial lymph nodes. Preoperative lym­phoscintigraphy and sentinel node biopsy can be per­formed safely in cases of conjunctival melanoma, thereby avoiding lymph node dissection and adjunc­tive radiotherapy.

Although experience with management of conjunc­tival melanoma is limited, 15 surgical excision, fol­lowed by cryotherapy to control microscopic fronds

of residual tumour cells or premalignant cells, is the first choice for a malignant tumour. !0,1 3 Cryotherapy widens the margins of excision and must be delivered to the base from which the nodule was excised if there is a fear of residual tumour along the deep surgical margins. Melanomas are sensitive to cryotherapy, and complications are minimal if only the quadrant of conjunctiva is treated; complications are more trou­blesome when large areas, especially of the bulbar and palpebral conjunctiva, are treated. Since in our case the flat melanoma that would be left behind after surgical excision of the nodule could become the pre­cursor for later invasive melanoma, our strategy was to treat the flat melanoma by cryotherapy.

Recently Finger, Czechonska and Liarikos 16 inves­tigated the role of 0.04% mitomycin C in 10 patients with conjunctival melanoma and concluded that topi­cal use of mitomycin C is very promising as adjunc­tive therapy and may be effective as primary treat­ment of superficial primary acquired melanosis with atypia but without nodules.

Our patient's melanoma had multiple features indi­cating a poor prognosis: diameter greater than 1.5 mm, involvement of the palpebral conjunctiva, fornix and caruncle, multifocal origin, vertical growth and pigmentation of the lower lid. However, despite these features, his visual acuity after excision of the tumour was 6/9, and after 18 months there was no evidence of recurrence, which is rare with a giant malignant melanoma of the conjunctiva. The reason may be that the tumour had exophytic growth.

The goal of treatment of conjunctival melanoma should be to eradicate the tumour, prevent local recur­rence and, above all, prevent metastasis and death. Our patient was treated by judicious excision of the lesion combined with cryotherapy. We believe that deliver­ing cryotherapy to the flat areas of obvious clinical involvement as well as to a generous surrounding area could forestall invasion and simplify management. It appears that in high-risk patients metastasis occurs before surgery can be performed. Exenteration is therefore not logical, because conjunctival drainage is not posterior, into the orbit, which lacks lymphatics. Removing the orbit and ocular tissue is merely a mat­ter of surgical convenience rather than a biologic necessity. Why disfigure these patients, especially the older ones, such as ours? Moreover, mutilating treat­ment (exenteration or enucleation) has not shown a statistically significant difference in outcome as com­pared with conservative treatment. 17 Cryotherapy as a

Conjunctival malignant melanoma-Malik et al

supplement to excisional biopsy has been effective in preventing tumour recurrence. 18•19

We conclude that giant conjunctival malignant melanoma can safely be treated by wide excision combined with judicious application of cryotherapy, provided the patient undertakes regular follow-up assessment for evidence of recurrence.

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18. Shields JA, Shields CL, Depotter P. Surgical approach to conjunctival tumors: Lynn B. Macmahan Lecture. Arch Ophthalmoll994;ll5:808-l5.

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Key words: malignant melanoma, conjunctival neoplasm, prognosis, cryotherapy, treatment outcome