Mystifying joint pains: Acute lymphoblastic leukemia presenting as systemic onset juvenile idiopathic arthritis

Objectives: Acute Lymphoblastic Leukemia (ALL) in children presents with varied manifestations. At times, they may mimic symptoms and signs of Systemic onset Juvenile Idiopathic Arthritis (SoJIA). We analyzed children with ALL who were initially diagnosed as SoJIA thus leading to delay in diagnosis and treatment of ALL. Material and Methods: Retrospective study of records of 18 children diagnosed as ALL at our center between the period of January 2016 and December 2020, and who were initially diagnosed as SoJIA. Results: All 18 children presented with fever and joint pains involving large joints such as knee, ankle, wrist, and elbow. Seven (38.8%) cases had associated hepatosplenomegaly and three (16%) had lymphadenopathy at the time of presentation. Ten out of 18 children (55.6%) had normal peripheral complete blood counts. The duration from the time of onset of symptoms to diagnosis of ALL ranged from 15 days to 7 months in these cases. Four children had received steroids as treatment of SoJIA before they were diagnosed with ALL. Conclusion: Possibility of ALL must be ruled out in all cases suspected of having SoJIA, as leukemias may not always present with typical signs like hepatosplenomegaly, lymphadenopathy, or cytopenias. It will prevent delay in diagnosis and treatment of ALL. Administration of steroids to these patients for SoJIA, adversely affects post-ALL treatment outcomes.