Atypical Case of Presumed Bartonella henselae Osteomyelitis in a Child with Cat-Scratch Disease Mimicking a Malignant Bone Tumor

Vollständiger Abstract

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Background/Objective: Bartonella henselae, the causative agent of cat-scratch disease (CSD), usually causes a self-limiting zoonotic infection. Osteomyelitis is a rare but increasingly recognized manifestation, particularly in children, and may closely mimic malignant or other infectious bone diseases. We present a case of multifocal pediatric Bartonella henselae osteomyelitis and discuss the associated diagnostic and therapeutic challenges in the context of the current literature. Case presentation: We report the case of a previously healthy 10-year-old girl who presented with a one-month history of fever, fatigue, limping, and progressive thigh and groin pain following cat-scratch exposure. During the course of the illness, she developed unilateral facial nerve palsy and Parinaud oculoglandular syndrome. Initial laboratory investigations demonstrated elevated inflammatory markers and reactive thrombocytosis. Serological testing for Bartonella henselae was positive for both IgM and IgG antibodies, whereas polymerase chain reaction (PCR) testing of both peripheral blood and the bone biopsy specimen was negative. Plain radiographs were unremarkable; however, magnetic resonance imaging (MRI) revealed multifocal lesions involving the right femoral diaphysis, right pubic bone, and left iliac wing, together with focal hepatic and splenic lesions suggestive of disseminated disease. Because of the radiological suspicion of malignancy, a femoral bone biopsy was performed and demonstrated osteomyelitis with necrosis and microabscess formation, without evidence of malignancy. Following targeted antimicrobial therapy, the patient showed rapid clinical and laboratory improvement, with progressive regression of the lesions on follow-up MRI. Conclusions: Bartonella henselae osteomyelitis should be considered in the differential diagnosis of multifocal bone lesions in children, particularly in patients with a history of cat exposure. Because the disease may closely mimic malignancy both clinically and radiologically, establishing the diagnosis requires careful integration of epidemiological, clinical, serological, radiological, molecular, and histopathological findings. Early recognition and appropriate antimicrobial treatment are associated with an excellent prognosis.