Abstract Introduction Neuroepithelial tumors with PATZ1 fusion are rare pediatric brain tumors that exhibit histological diversity and varying degrees of malignancy. There is no standard treatment, and the search for effective regimens is underway. We report a case of EWSR1-PATZ1 fusion-positive neuroepithelial tumor with diffuse leptomeningeal dissemination successfully treated with D-actinomycin and TMZ combination therapy. Case: A 15-year-old female was diagnosed her fourth ventricle tumor with meningeal dissemination at her age of 3 years and 7 months. She underwent partial resection of her tumor and pathological diagnosis was glioneuronal tumor Gr1. Immunostaining was positive for GFAP and Olig2, and the mitosis index was less than 1/10 HPF. She was treated with platinum-based chemotherapy to stabilize her tumor for three years. In the next seven years, no chemotherapy was given and four times of craniotomies and twice cranio-spinal irradiations (CSI) with local boost were performed. After the second CSI, she required Bevacizumab therapy for her radiation necrosis. Her recent tumor histology showed a higher-grade tumor with glial cell predominant, mixed atypical neurons with eosinophilic sporocytes, local necrosis and multiple blood vessels. EWSR1-PATZ1 fusion was detected of that specimen. So, we tried to treat her with D-actinomycin on the report of Alharabi et al. as a combination therapy with TMZ. Her leptomeningeal dissemination showed continuous improvement during 5 cycles of combination therapy with D-actinomycin and TMZ at 3-week intervals No adverse effect was observed until she stopped chemotherapy due to hydrocephalus. Conclusion D-actinomycin and TMZ combination therapy seemed worth trying as a 1st line therapy for EWSR1-PATZ1 fusion positive tumors. Molecular genetic analysis should be aggressively performed in rare brain tumors, which may expand the treatment options not only for molecular targeted therapy but also for chemotherapeutic agents that are not commonly used in brain tumors.
Kiyotani et al. (Fri,) studied this question.