Spontaneous Necrosis of a Large Choroidal Melanoma: Unusual Presentation in a 49-Year-Old Male

Abstract

Purpose: To demonstrate a case of massive vitreous haemorrhage obscuring the underlying diagnosis of a large mixed-cell choroidal melanoma which had undergone spontaneous necrosis.

Case report: A 49-year-old man in good general health suddenly lost vision in his right eye due to an extensive vitreous haemorrhage 1 day after a workout at the gym. He reported good vision prior to that without any symptoms of flashes, floaters, or shadows. He was referred to the vitreoretinal department of a tertiary eye hospital, where he presented with a drop in vision to light perception only in the right phakic eye. Pars plana vitrectomy was performed in the right eye, which revealed intraoperatively massive retinal ischemia and choroidal haemorrhage, but no obvious tumour mass that could have been biopsied. The vitrectomy cassette specimen was sent for histopathology, where "ghost-like" melanoma cells were identified. The eye was subsequently enucleated, revealing an extensively necrotic and haemorrhagic choroidal melanoma of mixed cell type with only small viable tumour foci at the base and almost complete lysis of the detached retina.

Conclusion: Some uveal melanomas (UMs) undergo spontaneous necrosis due to rapid growth, with the centre of the tumour outstripping its established blood supply in the "watershed area" of the eye, and becoming hypoxic with associated necrosis of intraocular structures. Such UMs are often associated with haemorrhage and/or inflammation and usually cause significant destruction of ocular tissues, resulting in enucleation as the only treatment option.

Keywords: Hyphaema; Necrotic melanoma; Spontaneous necrosis; Vitreous haemorrhage.

Fig. 1

a The dense haemorrhagic hyphaema of the right eye of the 49-year-old patient seen on presentation to the tertiary referral clinic. b Congested and dilated “sentinel” vessels in the conjunctiva of the same right eye at higher power. c, d Orga­nised vitreous haemorrhage viewed on ultrasound, with potential connection with the focally thickened choroid.

Fig. 2

a High-power histological section of the endoresection specimen, demonstrating numerous pigmented melanoma cells on a background of lytic tumour cells (H&E stain). b Immuno­staining of the endoresection sample showing clear positivity of the tumour cells for MelanA (magnification ×60). c Low-power magnification of the enucleated globe demonstrating a near-total necrotic partially pigmented mass in the posterior segment of the eye, with extensive retinal detachment and fibrinous synechiae between the retina and the distorted posterior iris. d Higher magnification of the inset box in c showing an area of viable tumour (H&E), which is seen better again at higher magnification of the area within the inset box of d in e.

Fig. 3

a BAP1 immunohistochemical staining showing clear nuclear positivity of the residual tumour cells for this marker. In the necrotic area (N), the melanoma cells lose their reactivity for both MelanA and BAP1 (magnification ×20; DAB chromogen). b A large capillary within the necrotic choroidal melanoma showing fibrinoid necrosis-like changes of its walls (H&E staining). c The necrotic choroidal melanoma at the optic disc showing extensive pigmentation and scattering of melanophages, which extend up to the lamina cribrosa of the optic nerve (ON) (H&E staining). d Scleral (Scl) thickening at the base of the tumour caused by oedema as well as chronic inflammatory infiltrates (arrow). e Proteinaceous fluid is seen between the necrotic choroidal melanoma with the overlying dissolved retina (R) and the posterior surface of the iris leaf and the detached ciliary body (CB) (H&E staining). f An extensive neovascular membrane is present overlying the ­anterior iris surface and obstructing the chamber angle (arrow). Schlemm's canal (SC) is filled with blood.