CASE REPORTA three year old boy was admitted to our hospital with history of high grade continuous fever of three weeks duration with no associated symptoms. He had been admitted in two other hospitals prior and had been administered multiple intravenous antibiotics. There was no significant past history. Examination revealed an ill looking child with pallor, icterus, presence of small cervical and axillary lymphadenopathy (1x1 cm), hepatosplenomegaly with polyserositis manifesting as moderate ascites and bilateral pleural effusion. There was no rash or arthritis. Initial investigations included haemoglobin 90 grams/L with positive direct coombs test, white blood cell (WBC) counts 20.7 x 10 9 /cu.mm with 80% polymorphs and platelet count 5 lakhs/cu.mm. The liver function tests (LFT) showed total bilirubin of 4 mg/dl with indirect fraction 2 mg/dl, normal enzymes and albumin 25 gram/L. The renal functions were normal. He had erythrocyte sedimentation rate (ESR) of 70 mm/hour and C-reactive protein of 80 mg/L. There was no organism isolated in blood culture and work up for common infections like enteric fever, malaria; leptospirosis and scrub typhus were negative. Broad spectrum antibiotics were started. Antinuclear antibody test was negative. Skiagram of the chest showed bilateral ABSTRACT Anaplastic large cell lymphoma (ALCL) in children can present with a broad spectrum of clinical manifestations which apart from nodal and extra nodal disease include paraneoplastic phenomena that can mimic an infection or inflammatory illness leading to delayed diagnosis. The following case report describes a child with prolonged fever, hepatosplenomegaly, polyserositis and extreme neutrophilia masquerading as an infection or inflammatory disorder for long before the definitive diagnosis of ALCL was made. This case highlights the rare paraneoplastic phenomena in ALCL and the heightened need to suspect this disorder when the search for underlying infections and connective tissue disorders are not conclusive.