Mechanisms of Optic Nerve Invasion in Primary Choroidal Melanoma

Cauda equina syndrome as the initial presentation of uveal melanoma metastasis

PURPOSE

Uveal melanoma extension to the central nervous system (CNS) is exceedingly rare, and can occur through optic nerve invasion. We report a rare clinical case that presented with cauda equina syndrome as the initial manifestation of metastasis of choroidal melanoma, and showed neurotropic extension by histopathology. Our patient did not demonstrate any evidence of systemic metastasis otherwise.

OBSERVATIONS

A 60-year-old male patient with treated choroidal melanoma in his right eye, with presumed clinical control, developed radiation-induced neovascular glaucoma refractory to medical therapy. The eye required enucleation for pain control. One month post-enucleation, he presented to the emergency department with severe abdominal pain, urine retention, constipation, and leg weakness. Magnetic resonance imaging (MRI) of the spine showed extensive leptomeningeal involvement along the entire spinal cord and the cauda equina. On further inquisition, the patient noted prior visual field defect in the contralateral eye. Brain MRI revealed intracranial metastasis with chiasmal involvement. The patient underwent radiotherapy for the brain and spine to improve his symptoms, and was ultimately transferred to palliative care.

CONCLUSION AND IMPORTANCE

Optic nerve invasion in uveal melanoma may lead to neurotropic spread of melanoma cells with risk of intracranial and spinal cord metastasis. Neurological symptoms should raise the suspicion of clinicians regarding this complication, which is associated with increased melanoma-related mortality.

Optic nerve invasion of non-juxtapapillary uveal melanoma: a rare occurrence

A 44-year-old man presented with complaints of pain and discomfort in his left eye (OS). On examination, he had bare perception of light in OS and had a diffuse pigmented mass lesion in the nasal quadrant of the bulbar conjunctiva, associated with neovascularisation of the iris and iridocyclitis, with no fundus view. Intraocular pressure OS was 40 mm Hg. B-scan ultrasonography OS revealed an intraocular mass with thickened sclerochoroidal complex. A clinical diagnosis of OS ciliochoroidal melanoma with extraocular extension was made. He underwent OS extended enucleation with implant. Histopathological examination confirmed the diagnosis of ciliochoroidal melanoma with tumour extension into the optic nerve posteriorly and the extrascleral tissues anteriorly. There was no evidence of systemic metastasis. Even in a case of non-juxtapapillary uveal melanoma, poor vision and high intraocular pressure are clinical indicators of optic nerve tumour invasion.