Pleural Metastatic Melanoma with Refractory Hemorrhagic Effusion: A Case Report.

Pleural melanoma is an exceptionally rare and aggressive form of malignancy with high mortality rate. We report a 57-year-old male of pleural metastatic malignant melanoma that manifested as refractory hemorrhagic pleural effusion. Imaging studies revealed a substantial right-sided pleural effusion accompanied by pleural nodules. Thoracoscopy uncovered diffusely distributed black nodules on the parietal pleura. Biopsy and immunohistochemistry confirmed the diagnosis of pleural malignant melanoma. Despite antitumor therapy combining pembrolizumab and temozolomide, he deteriorated rapidly, ultimately resulting in death. We underscore the importance of considering malignant melanoma in the differential diagnosis of unexplained hemorrhagic pleural effusion. Thoracoscopy plays a pivotal role in achieving a fast definitive diagnosis. A high proliferation index, such as an elevated Ki-67 indicates a rapid poor prognosis.