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Editor,—We report an unusual case of a cutaneous malignant melanoma which metastasised to the conjunctiva in one eye and the choroid in both eyes nearly 2 years after the initial presentation.
A 42 year old white man presented with a history of a small superficial black mark in the temporal aspect of the right eye, which had increased in size for the past 2 months. There was no significant ocular history. Two years earlier he had had a large malignant melanoma, 4.5 × 3.5 cm, removed from his lower back. On histopathology, this had been diagnosed as a superficial spreading type (Clarke's level IV with Breslow thickness of 3.5 mm). The mitotic count was 5 per 10 high power field (HPF) with a sparse lymphocytic infiltrate seen at the edges. It had been excised completely with no vascular or lymphatic invasion seen in the section. He had been thoroughly screened and a computed tomograph (CT) scan of the abdomen and head had not revealed any metastases. Subsequently, he had been followed up on a 4 monthly basis over the next 2 years and no recurrences had been found. During this period he developed a severe form of asthma which was controlled by oral prednisolone 25 mg per day. He otherwise felt well and on examination seemed to be in good general health. An enlarged lymph node was found in his left axilla. Visual acuity was 6/6 in the right eye and 6/5 in the left eye. Examination of the anterior segment in the right eye revealed a small superficial blackish brown mark about 3 mm in size on the lateral aspect of the bulbar conjunctiva. Left eye anterior segment examination was normal. The intraocular pressure was 17 mm Hg in both the eyes. Fundus examination of both the eyes revealed multiple, widespread, irregular subretinal pigmented deposits (Fig 1), some flat and some slightly elevated. There was no associated cataract or retinal detachment. His creatinine levels were found to be raised at 253 μmol/l, urea at 14.5 mmol/l, and lactate dehydrogenase at 443 IU/l. Urine examination showed both blood and protein present.
A diagnosis of cutaneous malignant melanoma with simultaneous metastases to the conjunctiva and choroid and possible widespread metastases was made. The patient was counselled and referred to the oncologist for possible chemotherapy. Surgery with a wide excision of the conjunctival lesion was performed the next day and the tissue was sent for histopathological examination. It was reported as consisting of a dense cellular infiltrate in the subepithelial tissue, with atypical melanocytes without any melanocytic activity in the overlying surface epithelium. The tissue showed a positive staining for S100 protein and HMB45 antibody, both of which are specific for malignant melanoma. There was no pre-existing naevus and this was compatible with a metastatic malignant melanoma (Fig 2).
CT scans of the abdomen and the head revealed no metastatic disease. Within a week he developed abdominal pain and headache with vomiting which was relieved by dexamethasone and was thought to be due to meningeal metastases. Chemotherapy was instituted with weekly intravenous vindesine 4 mg/m2 and tamoxifen 160 mg orally. Four days later he developed severe nose bleeds with clots. His platelet count at that point was normal and he was thought to have metastases in the postnasal space. His condition deteriorated rapidly with development of right sided pleuritic chest pain and haemoptysis and he died 3 weeks later.
Secondary metastatic disease in the eye is rare compared with other sites in the body and simultaneous secondaries in both anterior and posterior segment are highly unusual.1 The incidence of histopathologically demonstrable cutaneous malignant melanoma metastasising to these sites was seen in five of 15 cases (33%) with disseminated cutaneous malignant melanoma in an necropsy series and is thought to be more common in men.2 The presentation in the eye has been variously described as ranging from distinct tumours in the fundus or small diffuse infiltrates, anterior uveitis refractory to treatment, iris heterochromia, brownish coloured hypopyon due to tumour cells, diffuse pigmentation of the iris and the lens, aqueous and vitreous seedlings, and conjunctival pigmentation.3 4Patients can present with pain and redness due to secondary glaucoma caused by infiltration of the trabecular meshwork or angle closure due to an annular haemorrhagic choroidal detachment.5 Retinal deposits are very rare and may cause blurred vision.6Differentiation between secondary melanomas in the choroid and a primary melanoma is important in order to decide on the type of management. Bilateral diffuse uveal melanocytic proliferation is an important differential diagnosis in our patient but he had no associated cataract, retinal detachment, or severe visual impairment. The time interval between the initial presentation of the skin lesion and the occurrence of metastases may vary from months up to 10 years.3 7 The occurrence of ocular metastases usually indicates grave prognosis owing to widespread visceral disease, as was the case in our patient. He had undergone regular thorough screening for 2 years but no signs of metastases were found during this period. The first external sign of secondary disease was the presence of the conjunctival lesion, which led to the discovery of the intraocular lesions and the axillary node involvement. Metastases to the conjunctiva from a cutaneous malignant melanoma is again very rare (less than 1%) and is usually associated with secondaries elsewhere in the eye.8 These need to be differentiated from other conditions such as primary acquired melanosis, naevus, adrenochrome deposits, direct extensions from ciliary body melanomas, and foreign body granulomas. The mode of treatment of metastatic cutaneous malignant melanoma in the eye can range from local excision as in small localised iris tumours, and enucleation for a painful blind eye or palliative treatment comprising chemotherapy and radiotherapy if the disease is widespread, as is often the case.1 Patients with a single choroidal metastasis may be considered for radioactive plaque treatment.7 Previous studies have reported a median survival rate of 72 days with a maximum survival of 183 days and less than 10% survive up to 8 months after the onset of ocular symptoms.2 Although the survival rates are partly related to the depth of the dermal invasion9 ocular metastases with only superficial spreading type of melanomas have been reported and this was also true of our patient. Within days of being diagnosed as having ocular metastases, he developed signs of widespread secondaries, which led to his death within weeks.
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