Sir,

A case of spontaneous regression of the melanoma is presented.

Case report

A 56-year-old female was referred to Ocular Oncology service, complaining of photopsiae in the left eye for 4 months. She had no significant past ocular or systemic problems. On examination, her visual acuity was 6/6 in both eyes. Anterior segment examination and intraocular pressure were normal in both eyes. Fundus examination was normal in the right eye. In the left eye, there was an amelanotic lesion 9 × 9 × 3.7 mm3 superonasal to disc. There was overlying serous detachment and some superficial haemorrhages (Figure 1a). She was previously seen in the referring hospital 8 years ago, and the fundus was normal in her left eye at that time.

Figure 1
figure 1figure 1

(a) Coloured fundus photograph on presentation, showing the raised lesion with hemorrhage and serous retinal detachment. (b) Coloured fundus photograph 12 months after initial presentation, showing resolution of the melanoma with residual chorioretinal degeneration. (c) B-scan ultrasound at presentation, showing a choroidal lesion with acoustic hollowness. (d) A scan at presentation, showing low internal reflectivity. (e) FFA at presentation, showing masking and intrinsic vascularity in the lesion. (f) FFA at 12 months, showing chorioretinal atrophy (window defect).

Full size image

Fundus flourescein angiography (FFA) showed intrinsic vascularity in the lesion (Figure 1e). The B-scan was showing dome-shaped lesion with acoustic hollowness and absence of choroidal excavation (Figure 1c), with low-medium internal reflectivity on A-scan (Figure 1d) and intrinsic vascularity. A provisional diagnosis of choroidal melanoma or choroidal metastasis was made and she was extensively investigated for primary lesion. FBC, LFT including gamma GT, mammography, and X-ray of the chest were normal. CT thorax was showing a small nodule in the left lobe of the thyroid, but there was absence of lymphadenopathy. A fine-needle aspiration biopsy of the lesion confirmed that it was benign. CT abdomen was showing gall stones and a small cyst in the right ovary. The diagnosis at this stage was changed to a choroidal melanoma. Plaque radiotherapy was considered as a treatment option at this stage, but as it would compromise the vision the patient decided to wait till there was definite evidence of growth.

It was decided to observe the lesion and the patient was reviewed closely in the eye clinic; 8 months after her initial visit the exudation started resolving, with decrease in the size of the lesion confirmed on B scan ultrasound. This was followed by regression of the melanoma other than a small central nodule. Over the next 4 months, the lesion regressed slowly. At 1 year after the initial presentation, it had regressed to a small melanoma (1 × 1 × 1 mm3) with chorioretinal scarring around (Figure 1b). FFA at this stage showed chorioretinal atrophy (window defect) with underlying choroidal vessels, with the absence of intrinsic vascularity (Figure 1f).

The patient has been followed up in the eye clinic for the last 3 years, with no recurrence of the choroidal melanoma.

Discussion

Spontaneous regression of choroidal melanomas is quite rare.1 It has been well documented with several other tumours, including cutaneous melanomas.2 Most tumours that undergo either partial or complete3 spontaneous regression eventually recur.2 Complete resolution of one melanoma with a new tumour in the same eye has also been reported.6 In cases of cutaneous melanomas, regression is associated with depigmentation clinically and degenerative tumour cells with inflammatory cells histologically.4

Shields et al5 have reported three cases of incomplete spontaneous regression of choroidal melanomas in more than 8000 patients, with choroidal melanoma with all of them needing further management.

The possible mechanism of regression of tumours is not certain. The possibilities include hormonal influences, immunological factors, tumour cell necrosis, and inhibition of angiogenesis.2

In our case, at initial presentation choroidal metastasis was considered as a differential diagnosis, but the diagnosis was changed to melanoma based on the A and B scan appearance, fundus fluorescein angiography, and the absence of a systemic primary. Inflammatory aetiology was less likely as there was no vitreous activity, with the absence of any signs of inflammation in the contralateral eye. Choroidal excavation was absent, though this may be difficult to demonstrate in small melanomas.

This case illustrates an uncommon presentation of a small choroidal melanoma where the tumour regressed on observation over a 12-month period, with no recurrence of the tumour.