Purpose:
To share the experience of interpretation pitfalls in intracranial lesions in melanoma and treatment related side effects within a tertiary cancer centre 

Approach/Methods:
Melanoma can metastasise to the intracranial compartment. The clinical presentation, current treatment regime and treatment related effects are all key in correct interpretation of radiological findings. Each case is discussed separately with timelines and management decisions. 

Findings/Discussion:

Case 1. Patient on melanoma surveillance presented acutely with neurological symptoms. Routine imaging showed new enhancing white matter lesions. Clinical question: is this tumour relapse or a new aetiology? Treatment with immunotherapy aggravated the lesion burden. New aetiology more likely and management plan changed based on radiological findings. On stopping immunotherapy and starting steroids the lesions resolved. This was an example of denovo demyelination.

Case 2. Patient on immunotherapy for metastatic melanoma arising in the thigh. Routine intracranial MR imaging revealed new lesions arising in the right cerebral white matter. Clinical question: is this tumour relapse, treatment side-effect or a new aetiology? Upon treatment withdrawal and steroid administration the lesion resolved. This was an example of immunotherapy related demyelination.

Summary/Conclusion:
Melanoma metastases to the brain can be small and affect the meninges as well as the grey and white matter. Immunotherapy is a part of the treatment options in melanoma and can have its own toxic effects in the intracranial compartment. 

Melanoma patients can also present with non-related pathologies in the intracranial compartment. Differentiating these separate aetiologies have significant implications in patient outcomes and health economics. Close clinical and radiological correlation is the key to reducing risk and improving outcomes.

Intracranial Manifestations of Disease and Treatment Effects in Melanoma Patients

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