From Cellulitis to Bifocal Forearm Osteomyelitis: An Exceptional Presentation Of Invasive Mucormycosis in a Child with Acute Lymphoblastic Leukemia, a Case Report

Invasive mucormycosis is a rare but life-threatening fungal infection that primarily affects immunocompromised patients.We report the case of a 6-year-old boy with B-cell acute lymphoblastic leukemia who developed rapidly progressive necrotizing cellulitis of the left forearm during induction chemotherapy.Despite broad-spectrum antibacterial therapy, the lesion evolved with deep soft-tissue extension and bifocal osteomyelitis involving the ulna and the radius.Definitive diagnosis was established by histopathological examination of deep surgical specimens demonstrating broad, aseptate hyphae consistent with Mucorales.Management required aggressive surgical debridement and liposomal amphotericin B. The clinical course progressed to chronic osteomyelitis with residual wrist deformity; however, sustained bone marrow remission was maintained.Because intensive myelosuppressive chemotherapy was temporarily contraindicated due to active invasive fungal infection, blinatumomab was administered as a bridging immunotherapeutic strategy.This case highlights the importance of early deep tissue sampling in refractory cellulitis in neutropenic children and underscores the role of combined medical-surgical management and adapted oncologic therapy in improving outcomes.