Background: Melanotic ependymoma (ME) is an extremely rare subset of ependymoma characterized by cytoplasmic and extracellular deposition of melanin, with no case series having been reported to date. The aim of this study was to analyze the clinical manifestations, pathological and radiological features, treatment, and follow-up data, and to discuss the diagnosis, management and prognosis of ME.
Methods: We retrospectively reviewed the clinical and imaging data of six patients with primary ME. The diagnosis was based on radiological and pathological criteria. All the patients were treated surgically with gross total resection. The preoperative and postoperative neurological states of the patients were analyzed. All the follow-up data were obtained from office visits, and the long-term outcomes are presented and discussed.
Results: Patients presented with nonspecific symptoms. On magnetic resonance imaging (MRI), although a characteristic signal variation could be found reflecting the melanin component, individual appearances varied widely and were related to the content and distribution of melanin in the ME lesions. The characteristic ependymoma-related pathological appearance and specific immunostaining for glial fibrillary acidic protein and antimelanoma monoclonal antibody were revealed. During a mean follow-up period of 46.8 months, no local recurrences or distant metastases were observed.
Conclusions: The accurate diagnosis of ME depends on pathology. The histological grading used for ependymoma can be applied. Most MEs have a relatively benign course. Complete surgical resection alone is the treatment of choice for low-grade MEs, and the outcome may be favorable. Postoperative adjuvant radiotherapy can be considered for lesions with histologically anaplastic features.