NFS-01. EXTREMELY RARE CASE OF CHILDREN WITH NIJMEGEN BREAKAGE SYNDROME AND MEDULLOBLASTOMA – A THERAPEUTIC CHALLENGE

Abstract

Abstract BACKGROUND Nijmegen Breakage Syndrome (NBS) is an autosomal recessive inherited disorder characterized by DNA repair abnormalities. It manifests with heightened sensitivity to radiotherapy (RT) and predisposes individuals to neoplastic diseases. Antineoplastic treatment in NBS patients is particularly challenging due to concurrent immune disorders, intense toxicities, and contraindications for RT. Hematologic disorders, especially lymphomas, are among the most prevalent malignancies in NBS patients. Solid tumors in NBS are extremely rare, with only two pediatric cases documented in the literature, both succumbing due to severe complications of treatment. METHODS A review and analysis of the medical documentation of a child with NBS and MB treated at the Department of Pediatrics, Hematology, and Oncology, Gdansk, Poland, were conducted. RESULTS A genetically confirmed NBS girl displaying typical phenotypic features presents symptoms at the age of 2 years, such as headaches, reluctance to walk, and drowsiness. Imaging confirmed a tumor in the left cerebellar hemisphere, measuring 40x33x30mm, displaying radiological features consistent with Medulloblastoma (MB). The patient underwent gross total resection of the tumor. The pathology revealed a desmoplastic type of MB with SHH activation, TP53 wild type, and ongoing molecular analysis. Postoperative imaging confirmed clinical remission, and cerebrospinal fluid examination was negative. Considering the substantial toxicities of chemotherapy in NBS patients and the contraindications for RT, the patient received chemotherapy with reduced cytostatic doses. Treatment was complicated by profound and prolonged myelosuppression and infections. Currently, after completing six cycles of chemotherapy, the patient is still in remission. To maintain remission and address NBS, the patient will receive allogeneic bone marrow transplantation from a 9/10 HLA-matched unrelated donor. CONCLUSIONS Managing patients with NBS, complicated by neoplastic diseases, is exceptionally demanding and necessitates an individualized multidisciplinary approach. Modern diagnostic and therapeutic methods enhance the prospects of reducing the toxicity of oncologic treatment, improving quality of life, and extending overall survival.