485 The association between juvenile xanthogranulomas in neurofibromatosis type 1 patients and the development of leukemia: A systematic review

Importance: A subset of patients with neurofibromatosis type 1 (NF1) develop juvenile xanthogranulomas (JXGs), a non-Langerhans cell histiocytosis, and some these also myelomonocytic leukemia (JMML). Yet, associations are poorly delineated. Objective: Our objectives in this systematic review was to: (1) clarify the relationship between NF1, JXGs JMML identify that may benefit from additional screening, (2) describe clinical characteristics arising NF1. Evidence Review: literature search performed within PubMed database on July 7th, 2021. Articles were included if they peer-reviewed human studies, English, discussed any association JXG, and/or individual patient data. Findings: Sixty-five articles met eligibility criteria, which 181 patients. Fifty-six had NF1 JXG without (Group 1), 98 2), 18 (Group3), 9 4). Among 78 23% (18/78) developed leukemia, more specifically, 19% (15/78) JMML, is higher than what has been reported alone. Majority triple male (93%, 14/15) family history (67%, 8/12). Conclusions: findings suggest have an increased risk developing especially males Although remains rare, closer surveillance screening familial lesions be reasonable, particularly at early ages.