Differential Diagnosis for a 37-year-old Man with a Necrotic Left Axillary Lymph Node

• Single Most Likely Diagnosis
  • Metastatic cancer (e.g., breast, lung, or melanoma): This is considered the most likely diagnosis due to the presence of a necrotic lymph node, which often indicates malignancy. The axillary region is a common site for metastasis from various primary cancers.
• Other Likely Diagnoses
  • Lymphoma: Both Hodgkin and non-Hodgkin lymphoma can present with lymphadenopathy, and necrosis can occur, especially in aggressive types.
  • Cat-scratch disease: Caused by Bartonella henselae, this infection can lead to lymphadenopathy, which may become necrotic.
  • Tuberculosis or other mycobacterial infections: These can cause necrotic lymphadenitis, particularly in immunocompromised individuals or those from endemic areas.
• Do Not Miss Diagnoses
  • Infectious causes such as anthrax or plague: Although rare, these infections can be deadly and must be considered, especially if the patient has been exposed to animals or has a relevant travel history.
  • Kaposi's sarcoma: In immunocompromised patients, Kaposi's sarcoma can cause lymphadenopathy and necrosis.
• Rare Diagnoses
  • Kimura disease: A rare, chronic inflammatory disorder that can cause lymphadenopathy and eosinophilia, more commonly seen in Asian males.
  • Rosai-Dorfman disease: A rare histiocytic disorder that can present with lymphadenopathy, which may be necrotic in some cases.
  • Castleman disease: A rare disorder that can cause lymphadenopathy, which may be necrotic, especially in the unicentric form.

Each of these diagnoses has a different set of implications for treatment and prognosis, highlighting the importance of a thorough diagnostic workup.