Isolated Axillary Lymphadenitis Due to Bartonella Infection in an Immunocompromised Patient.

Bartonella henselae is a relatively uncommon pathogen that can present as a serious disease in immunocompromised patients. We present a case of a 76-year-old man with stable chronic lymphocytic leukemia (CLL) who presented to the emergency department (ED) with an onset of right axillary lymphadenitis after recovering from a recent cat bite on the ipsilateral finger. Doppler ultrasound demonstrated an irregular, circumscribed 5cm x 4cm, hypoechoic mass with mild vascular flow consistent with an enlarged abnormal lymph node. The patient was diagnosed with cat scratch disease and discharged on oral antibiotics with spontaneous drainage of the purulent materials in subsequent outpatient oncology visits. This case highlights the classic presentation of this rare disease in an immunocompromised patient with feline contact. Early antibiotics should be considered for at-risk and immunocompromised patients due to low sensitivity and specificity for Bartonella serologic tests. CLL can also present with similar progressive lymphadenopathy with severe systemic symptoms and extranodal involvement that requires emergent oncologic interventions and diagnostic vigilance.