Cat-Scratch Lymphadenitis Presenting with Right Upper Arm and Axillary Masses: a Case Report Mimicking Lymphoma and Potential Diagnostic Pitfall.

Background: Cat scratch disease (CSD) is an infectious disease caused by a cat's scratch, hard enough to break the skin's surface. Clinical manifestations include inflammatory lymphadenopathy and papular lesions at the site of the injury. However, it may be mistaken for a neoplasm-related process e.g., lymphoma due to its similar clinical presentation.

Objective: To report a CSD case in an Indonesian male presenting with mass-like symptoms in the oncologic ward of our center.

Case report: A 24-year-old male presented with painful and swelling masses in the right upper arm and right armpit for the last 4 months, enlarged progressively, and feverish for two days. Our initial differential diagnosis was lymphoma by history and routine physical examination, however. The patient reported a history of sleeping with his cat and recently experiencing a cat bite. We conducted the ultrasonography and lymph node biopsy to establish the final diagnosis and it was revealed to be related to CSD. The patient was treated with lymphadenectomy and azithromycin 500 mg bd for 7 days. The patient was completely treated with no additional complaints after two weeks of follow-up.

Conclusion: The differential diagnosis for CSD is relatively broad, including active infection, an ongoing inflammatory process, or a metastatic process; hence, thorough diagnostic approaches should be made in approaching CSD cases to avoid the pitfall or mistreatment in advance.