The Great Mimicker: Cutaneous Metastatic Melanoma Presenting as a Non-resolving Pleural Effusion

Although melanoma starts as a local disease, it can metastasize to other sites of the body including the lung, brain, liver, and intestines. However, pleural involvement is a rare presentation. Here, we present a case of a 57-year-old man with a history of stage IIA cutaneous melanoma, that relapsed 3 years after cutaneous resection, presenting with a non-resolving pleural effusion. Pleural fluid analysis was consistent with an exudative effusion, and pleural biopsy confirmed metastatic melanoma. The patient was treated with dual therapy of ipilimumab and nivolumab, as per National Comprehensive Cancer Network guidelines, with good response. Thus, we recommend having a high index of clinical suspicion for metastatic pleural melanoma when a patient with a history of cutaneous melanoma presents with a non-resolving pleural effusion.