Case Report: Atypical cat-scratch disease presenting as referred shoulder pain and deep lymphadenopathy in a pediatric patient.

Background: Cat-scratch disease (CSD) is a zoonotic infection attributable to Case summary: An 11-year-old female patient presented to the hospital with persistent fever accompanied by left shoulder joint pain and restricted movement of the left upper extremity. Physical examination upon admission revealed no superficial lymphadenopathy or characteristic cutaneous lesions. Following empirical broad-spectrum antibiotic therapy, the patient continued to experience recurrent febrile episodes, with persistently elevated inflammatory markers. Subsequent magnetic resonance imaging (MRI) of the shoulder joint and contrast-enhanced computed tomography (CT) of the chest demonstrated multiple enlarged lymph nodes in the left axillary, supraclavicular, and deep cervical regions. Further history-taking disclosed recent exposure to cats. Histopathological examination of an axillary lymph node biopsy (hematoxylin-eosin staining) revealed suppurative granulomatous lymphadenitis. These H&E histopathological findings are merely supportive rather than confirmatory evidence for CSD, as we failed to perform Conclusion: In pediatric patients presenting with fever of unknown origin accompanied by musculoskeletal symptoms, suboptimal response to conventional anti-infective therapy, and absence of superficial lymphadenopathy, the possibility of atypical cat scratch disease should be considered. A detailed assessment of contact history with domestic animals, along with prompt deep lymph node imaging evaluation and histopathological biopsy, facilitates early and appropriate clinical diagnosis. Implementation of targeted antimicrobial therapy may improve clinical outcomes in affected children.