Recurrent Malignant Melanoma Presenting as Isolated Pleural Metastases in a Patient with Chronic Lymphocytic Leukemia

Isolated pleural metastasis with pleural effusion is a rare occurrence in malignant melanoma. We report an unusual case of a patient with chronic lymphocytic leukemia (CLL) and recurrent pleural effusions. The pleural fluid cytology and immunohistochemistry profile were consistent with the diagnosis of CLL. However, chemotherapy with pentostatin, cyclophosphamide, and rituximab did not result in any meaningful clinical response. A video-assisted thoracoscopic surgery and biopsy of the affected nodular parietal layer of the pleura were consistent with malignant melanoma. Our case underlines the importance of having a suspicion for secondary causes of effusion in patients with CLL. We briefly discuss the mechanisms of an increased incidence of secondary cancers in CLL and the diagnosis of isolated pleural metastases in malignant melanoma.