Abstract
Background: We report a case of primary malignant melanoma of the brain.
Case: A 56-year-old male, presented with a chief complaint of decline in attensiveness and initiative accompanied by headache. Metastatic carcinoma of the brain was detected by CT, MRI and angiography of the brain. Tumorectomy was performed and the histopathologic diagnosis was malignant melanoma. Large atypical cells with a high N/C ratio were revealed in the cytology of spinal fluid. However, it was difficult to diagnose this case as malignant melanoma by cytology alone because the cells were lacking melanin pigment. The patient's condition was improved by chemotherapy, but increased melanin pigment and obvious nucleoli in the cytology of spinal fluid proved this case as malignant melanoma.
Conclusion: Cytological findings of spinal fluid at the autopsy were almost the same as the cytological findings during chemotherapy. Peritoneal dissemination was considered to be the result of V-P shunt, but the majority of the cells in peritoneal fluid were histiocytes which had devoured melanin pigments and a few melanoma cells mainly in the peritoneum of the Douglas pouch.
