Malignant melanoma of the conjunctiva

Conjunctival melanoma: New insights in tumour genetics and immunology, leading to new therapeutic options

Recent developments in oncology have led to a better molecular and cellular understanding of cancer, and the introduction of novel therapies. Conjunctival melanoma (CoM) is a rare but potentially devastating disease. A better understanding of CoM, leading to the development of novel therapies, is urgently needed. CoM is characterized by mutations that have also been identified in cutaneous melanoma, e.g. in BRAF, NRAS and TERT. These mutations are distinct from the mutations found in uveal melanoma (UM), affecting genes such as GNAQ, GNA11, and BAP1. Targeted therapies that are successful in cutaneous melanoma may therefore be useful in CoM. A recent breakthrough in the treatment of patients with metastatic cutaneous melanoma was the development of immunotherapy. While immunotherapy is currently sparsely effective in intraocular tumours such as UM, the similarities between CoM and cutaneous melanoma (including in their immunological tumour micro environment) provide hope for the application of immunotherapy in CoM, and preliminary clinical data are indeed emerging to support this use. This review aims to provide a comprehensive overview of the current knowledge regarding CoM, with a focus on the genetic and immunologic understanding. We elaborate on the distinct position of CoM in contrast to other types of melanoma, and explain how new insights in the pathophysiology of this disease guide the development of new, personalized, treatments.

Update on conjunctival pathology

Conjunctival biopsies constitute a fairly large number of cases in a typical busy ophthalmic pathology practice. They range from a single biopsy through multiple mapping biopsies to assess the extent of a particular pathological process. Like most anatomical sites, the conjunctiva is subject to a very wide range of pathological processes. This article will cover key, commonly encountered nonneoplastic and neoplastic entities. Where relevant, sections will include recommendations on how best to submit specimens to the ophthalmic pathology laboratory and the relevance of up-to-date molecular techniques.

Parotidectomy and neck dissection in the management of conjunctival melanoma: are they necessary?

OBJECTIVES/HYPOTHESIS

The objectives of this study were to review traditional techniques for the management of conjunctival melanoma and assess the need for parotidectomy and neck dissection in the management of conjunctival melanoma.

STUDY DESIGN

Retrospective review.

METHODS

This study was a retrospective review conducted in a tertiary academic medical center of patients diagnosed with conjunctival melanoma over a 20-year period

RESULTS

There were 39 patients diagnosed with conjunctival melanoma identified from January 1990 to December 2010. Follow-up varied from 2 to 201 months (median, 25 months). Of the patients, 16 (41%) had local recurrences at the primary site, two (13%) of whom later presented with parotid disease. One patient with parotid recurrence had a subsequent neck dissection for confirmed metastatic spread. No patient in this series had metastatic cervical disease without initial spread to the parotid. The probability of disease-free survival at 1, 2, and 5 years was 77%, 68%, and 50%, respectively. The probability of parotid free progression at 1, 2, and 5 years was 100%, 96%, and 90%, respectively.

CONCLUSIONS

Conjunctival melanoma is a rare malignancy traditionally managed with aggressive treatment to optimize local control. The role for staging parotidectomy with or without neck dissection has been heavily debated. Based on our review, parotidectomy only needs to be undertaken when high suspicion for metastatic spread is present, such as a palpable or radiographically evident mass. In addition, without documented parotid disease, neck dissection is not required.

Malignant melanoma of the eyelid and palpebral conjunctiva treated with iodine-125 brachytherapy

OBJECTIVE

To evaluate the results on malignant melanomas of the eyelid and palpebral conjunctiva treated with iodine-125 (125I) brachytherapy with shielding of the eye.

DESIGN

Noncomparative case series.

PARTICIPANTS

Fourteen patients treated with 125I brachytherapy at an ocular oncology referral center from 1974 through 1996, all of whom had had previous debulking, incomplete resection, or recurrence after surgery.

INTERVENTION

A stainless steel pericorneal ring eyeshield was attached to the extraocular muscles, over which a lid was fitted to protect the cornea without touching it. Iodine-125 seeds in polythene tubes were inserted into the eyelid and attached to the lid margin for a single plane implant. In five cases additional seeds were glued on to the shield as well for a volume implant. A median dose of 37 Gy (range, 17.3-67.6 Gy) was given over the course of 113 hours (range, 47-190 hours) to the outer surface of target volume.

MAIN OUTCOME MEASURES

Local control is regarded as freedom from recurrence in those without measurable disease and complete clinical regression in those with measurable disease. Morbidity is assessed in terms of function and cosmesis. Survival is given from the time of the implant.

RESULTS

There was local control in 13 patients maintained from 11 to 227 months (median, 39 months). There were two recurrences at 8 and 13 months in the first patient who received 17.3 Gy. Late complications consisted of mild eyelid telangiectasia, mild eyelid atrophy, and loss of eyelashes in most patients. Five patients, four of whom had upper eyelid tumors, experienced a dry eye, which was managed with tear supplements, and one of these patients developed a cataract. A corneal ulcer developed in one eye, which later perforated after treatment of a subsequent bulbar melanoma and was exenterated. Another eye was enucleated after treatment for a subsequent melanoma in the fornix. Cosmesis was acceptable to patient and doctor in the other 12 patients. Vision was maintained in seven patients, reduced in two, and not recorded in the remaining three patients. Three patients died of hematogenous metastases at 44, 62, and 79 months after implant, one of bronchial carcinoma at 46 months and one of an astrocytoma at 39 months. All patients were clear of local disease. The remainder survived for a median of 45 months (range, 18-227 months).

CONCLUSIONS

Iodine-125 brachytherapy can be used as an alternative to wide excision or exenteration of these tumors. There was good local control, reasonable maintenance of vision, and good cosmesis.

Conjunctival melanotic lesions in Chinese: comparison with Caucasian series

Conjunctival melanotic lesions in Chinese were studied and compared with those of Caucasians. These lesions were diagnosed in Chinese patients over a two-year period. They were excised under the clinical diagnoses of nevi, primary acquired melanosis (PAM) and malignant melanoma. For the cases included, the histology slides and clinical information were reviewed. Eighteen cases of nevi and nine non-nevoid lesions were identified. Among the non-nevoid lesions, there were eight cases of basal cell hyperpigmentation (one congenital, five acquired, two unknown) and one malignant melanoma. Benign or atypical melanocytic hyperplasias (MH) were not seen. This pattern is very different from that of Caucasian series. Acquired hyperpigmentation is almost only seen in Chinese and seldom in Caucasians. On the other hand, atypical MH is only seen in Caucasians, and not in Chinese. We conclude that conjunctival hyperpigmentation is associated with ethnicity and does not progress to MH, whether benign or atypical. It should be recognised as a distinct entity of no malignant potential that is part of the PAM clinical spectrum.

Conjunctival melanoma

Conjunctival melanoma is an uncommon tumor that is likely to recur and carries an overall mortality rate of approximately 30%. The seemingly unpredictable and enigmatic character of this entity has initiated much debate over the past decades regarding the etiology, histogenesis, prognosis, and preferred management. This review outlines the historical perspective; incidence and demographics; etiologic factors; histogenesis; cytogenetic findings; clinical characteristics; histopathologic and ultrastructural features; differential diagnoses; classifications; management of primary, recurrent, and systemic disease; survival after conjunctival melanoma; and diverse factors of potential prognostic significance. Finally, a brief outlook on present and future research objectives is provided.

Prognostic factors in primary malignant melanoma of the conjunctiva: a clinicopathological study of 256 cases

A series of 256 consecutive cases of invasive primary conjunctival malignant melanomas was examined to identify clinical and histopathological prognostic factors. The follow up period varied between 0.3 and 45.9 years (mean 9 years, median 6.3 years). The 5 year survival rate was estimated at 82.9%, the 10 year survival rate at 69.3%. Multiple regression analysis with the Cox proportional hazards model was used to assess sex, age, and a number of baseline features of conjunctival malignant melanoma as possible prognostic factors influencing melanoma related mortality. In assessing each potential prognostic factor, the effects of all other factors were taken into account in the modelling process. Tumours in unfavourable locations--that is, those involving the palpebral conjunctiva, fornices, plica, caruncle, and lid margins, were associated with 2.2 times higher mortality compared with (epi)bulbar melanomas. Patients with mixed cell type tumours had about three times higher mortality compared with those with pure spindle cell melanomas, and histological evidence of lymphatic invasion by tumour cells was also a prognostic feature, carrying a fourfold increase in the death rate. Multifocal tumours were associated with a fivefold increase in mortality among those with tumours in favourable (epi)bulbar locations, but were not prognostic in patients with melanomas in unfavourable sites. The death rate was significantly higher in those with initial tumour thickness of more than 4 mm, but only among patients with unfavourably located melanomas. Sex, age, and clinical origin of the tumour (primary acquired melanosis, pre-existing naevus, or de novo) were not useful prognostic indicators in this study.

AgNOR counts in conjunctival malignant melanoma lack prognostic value

Using a silver staining technique, argyrophilic nucleolar organiser region-associated proteins (AgNORs) have been studied in routinely processed paraffin sections of 46 invasive malignant melanomas (MM) of the conjunctiva. The aim of this retrospective study was to assess the value of the AgNOR method as a prognostic indicator for this neoplasm. The 46 cases were divided into two groups: (A) 14 cases of MM that metastasised and caused death of the patient within 5 years of (histological) diagnosis, and (B) 32 cases of MM that did not metastasise and in which patients survived beyond 5 years. The mean of the AgNOR counts per nucleus was 7.03 (95% CI: 5.81-8.24) in group A, and 7.15 (95% CI: 6.53-7.77) in group B. A comparison using a multifactor analysis of variance (ANOVA) model, which corrected for possible confounding effect of tumour thickness, site, and cell type showed no significant difference in AgNOR counts between groups A and B (p = 0.8). Analysis by the Cox proportional hazards regression model showed that survival was not influenced significantly by the mean AgNOR number (hazard ratio: 0.92). Whereas the AgNOR technique may be used to distinguish benign from malignant melanocytic lesions of the conjunctiva, we conclude it has no value in predicting the outcome for patients with conjunctival MM.

Conjunctival malignant melanoma in Sweden 1969-91

Clinical information, follow-up and histopathological parameters of the primary lesions were assessed for all (45) individuals with conjunctival malignant melanomas in Sweden presenting during a 22.5 year period (1969 to mid 1991). The annual incidence of conjunctival malignant melanoma in Sweden was 0.0240 per 100,000. On average, two new cases were diagnosed each year (population 8.6 million in 1991). Sixty-two per cent of the lesions recurred, but re-growth in itself was not correlated to reduced survival. The actuarial 10-year survival proportion using life-table analysis was 70%. A significantly reduced survival due to tumour-related death was noted in patients with tumours with high mitotic indices, many epithelioid cells and in lesions exceeding 10 mm in diameter. Other factors that may influence survival are presented in the context of previous reports. The present policy in Sweden for treating patients with malignant melanoma of the conjunctiva is outlined and discussed.

Rare variants of malignant melanoma

The personal experience with 5 rare types of malignant melanoma is reviewed to point out some of the practical problems in the diagnosis and management of these tumors. The rare forms discussed are conjunctival, nasal, oral, vulvar, and penile melanomas. All pigmented lesions in the oral cavity, but not the penis or vulva, should be prophylactically excised as lesions in the mouth have a higher malignant potential. Local excision of all 5 forms of primary melanomas, no matter how locally advanced they may be, is the sole treatment. Nevertheless, anatomic constraints often preclude surgery with generous margins and consequently local recurrence, particularly for conjunctival, nasal, and oral primary lesions, is usually the major first failure in treatment. Lymph node dissection is only performed if the regional nodes are palpable at the time of first presentation. Elective lymph node dissections are not performed since the patients are often elderly, the lymphatic drainage is usually ambiguous or multiple, and the disease tends to spread hematogenously rather than lymphatically. Surgery still remains the cornerstone of treatment for these rare forms of melanoma but prognosis is very poor since surgery is often a palliative rather than a curative measure. Improved survival may depend on identifying more effective chemotherapeutic and immunologic agents.

Conjunctival melanocytic lesions in children

Seventy-one conjunctival melanocytic proliferations in patients 20 years of age or younger were examined. Sixty-five (91.5%) were nevi; there were three cases (4.2%) of racial or acquired melanosis, and three patients were identified who had malignant melanoma of the conjunctiva. The melanoma patients are presented in detail, and additional cases of conjunctival melanoma in children and adolescents reported in the literature are reviewed to determine factors that might influence prognosis. The number of cases is so small, however, that factors cannot be identified with confidence. Follow-up data are presented. Conjunctival nevi are relatively common in children, and appear to carry no risk for the development of melanoma during childhood. However, -conjunctival melanomas do occur rarely in children and have a variable prognosis.

Prognosis of conjunctival melanomas in relation to histopathological features

Twenty-six patients (age 29-85 years) with primary malignant melanoma of the conjunctiva were analysed for usefulness of various histopathological and immunohistochemical features of the primary, recurrent and metastatic tumours in evaluating their prognosis. The mean follow-up time was 5.5 years, ranging from 8 months to 17 years. Eight patients developed metastases and seven have died. The mean time from diagnosis to death due to metastasis was 3.8 years (range 1-6 years). The site of the primary tumour seemed to be most closely correlated to high metastatic risk. Only two of the sixteen limbal melanomas metastasised, whereas two of the four bulbar, all three tarsal and the only diffuse primary tumour caused metastatic disease. Two of the metastasising primary tumours were less than 1.5 mm thick, but all exceeded 0.8 mm in thickness. The mitotic rate, the amount of inflammatory infiltrate, the cell type or the presence of adjacent intraepithelial involvement did not obviously correlate to treatment outcome. Furthermore, the expression of S-100 protein and neuron-specific enolase (NSE), both suggested to be prognostic indicators in cutaneous melanoma, did not correlate to the tendency of the conjunctival melanomas to recur or metastasise.