Abstract
BACKGROUND: Cat scratch disease (CSD) is the most common human infection caused by Bartonella henselae (B. henselae). The main manifestation is self-limited lymphadenopathy that primarily affects adolescents, and typically resolves without treatment within 2-4 months. However, individuals with compromised immune systems or immunodeficiency require specific antibacterial therapy following diagnosis. Due to its low incidence, nonspecific clinical manifestations, and diagnostic limitations, this condition often poses challenges for clinicians in terms of missed diagnoses and misdiagnoses. CASE SUMMARY: The child was ultimately diagnosed with CSD. The primary manifestations included nocturnal fever, enlargement of lymph nodes in the neck, axilla and groin, and suspected brucellosis; however, both brucellosis tests conducted during the course of the illness yielded negative results. Bone marrow cytology indicated stimulated proliferation. Lymph node biopsy indicated hyperplasia of lymphoid tissue in the cervical lymph nodes (right), with combined immunohistochemical findings indicating reactive hyperplasia. Immunohistochemical analysis revealed CD20 B (+), CD3 T (+), BCL-6 (+), and BCL-2 (-). CD21 FDC networks were present and Ki67 expression in the germinal center was ~80%. Blood next-generation sequencing indicated B. henselae sequence number was 3. Serological test results demonstrated positive antibody response to B. henselae IgG (+), B. henselae IgM (+), Bartonella quintana (B. quintana) IgG (-) and B. quintana IgM (-), and the final diagnosis was CSD. CONCLUSION: In patients presenting with fever at night and swollen lymph nodes of unknown origin, CSD should be considered.