Chest wall pseudotumor in a child: an atypical presentation of bartonella infection mimicking a soft tissue neoplasm

Cat Scratch Disease (CSD), caused primarily by Bartonella henselae, typically presents with regional lymphadenitis. Atypical manifestations may mimic soft tissue tumors, posing significant diagnostic challenges in pediatric patients. To describe a pediatric case of chest wall pseudotumor initially suspected to be a soft tissue neoplasm, later identified as Bartonella infection, and to highlight the role of multimodality imaging in differentiating neoplastic from infectious lesions. The patient underwent laboratory testing, ultrasound, contrast-enhanced CT, FDG PET-CT, infectious disease screening, and lesion biopsy. Clinical and radiological evolution was monitored during hospitalization. PET-CT demonstrated intense FDG uptake (SUV 6) within the chest wall lesion and mild uptake in ipsilateral axillary lymph nodes (SUV 2.1). The lesion evolved into a draining abscess with fistulous tract. Biopsy revealed infectious inflammatory tissue consistent with Bartonella spp. infection, confirmed by serology. Targeted antibiotic therapy led to complete resolution. Atypical Bartonella infections may closely mimic soft tissue neoplasms on imaging. Integration of clinical, radiological, microbiological, and histopathological data is essential to avoid unnecessary invasive procedures.