Local anesthetic thoracoscopy for the diagnosis of metastatic pleural melanoma originated from oral malignant melanoma: case report and comments

BACKGROUND Oral malignant melanoma (OMM) is an aggressive tumor with very low survival rate and easy to metastasize. Pleural metastatic melanoma via primary OMM is rare. CASE PRESENTATION In this report, we presented a case of metastatic malignant melanoma of the pleura originated from OMM. A 54-year-old man without primary skin lesion was diagnosed multiple nodular shadows, pleural invasion, and pleural effusion by chest computed tomography (CT). One cyst-form tumor on the tongue base was observed by bronchoscopy, which was diagnosed as OMM by pathological examination and then was resected. After getting the tumor tissues from the pleura by pleural biopsy surgery, the diagnosis of pathological examination was pleural metastatic melanoma. Furthermore, tumor cells displayed a positive immunoreaction for melanocytic markers S100 and HMB-45 combining with positive vimentin and cytokeratin AE1/AE3. The patient was therefore diagnosed with metastatic melanoma of the left pleura and the primary melanoma was OMM. CONCLUSIONS According to this case, we could draw the conclusion that pleural metastasis from OMM was very rare and thoracoscopy preceded under local anesthesia is an important method for its accurate diagnosis.