Conjunctival Metastasis of a Cutaneous Melanoma.

Purpose: To report a patient who presented with a conjunctival tumour as a first sign of distant metastasis of cutaneous melanoma. The patient was treated successfully with BRAF/MEK-inhibitors and anti-PD-1 antibodies.

Methods: Clinical and histopathological examination of the conjunctival lesion.

Results: A 74-year-old man was referred to our hospital with a pigmented conjunctival tumour, 5 months after having been diagnosed with cutaneous melanoma on his right scapula with loco-regional axillary lymph node metastases. The conjunctival lesion was excised and showed a BRAF V600E mutation. Histopathology showed a melanoma with characteristics suspicious for metastasis, as the lesion did not have a relation with the overlying epithelium. Systemic screening showed multiple distant metastases of the cutaneous melanoma in spleen, liver, and bone. Systemic treatment with the combination of a BRAF-inhibitor (dabrafenib) and MEK-inhibitor (trametinib) was started and followed by a switch to an anti-PD-1 antibody (pembrolizumab). Twenty-two months later, the patient is alive and in good clinical health.

Conclusion: Conjunctival metastases of cutaneous melanoma may mimic primary conjunctival melanoma. A good medical history and systemic work-up are required to differentiate these diseases. Identification of the proper diagnosis including mutation analysis is crucial, allowing patients to benefit from newly introduced treatment strategies for metastatic cutaneous melanoma.