Differential Diagnosis for Axillary Lymphadenopathy
Single Most Likely Diagnosis
- Breast Cancer: This is the most common cause of axillary lymphadenopathy, especially in women. The proximity of the axillary lymph nodes to the breast tissue makes them a common site for metastasis.
Other Likely Diagnoses
- Infectious Mononucleosis: Caused by Epstein-Barr virus, this condition can lead to lymphadenopathy, including in the axillary region, especially in young adults.
- Cat-Scratch Disease: This bacterial infection, caused by Bartonella henselae, can result in axillary lymphadenopathy after a cat scratch or bite.
- Lymphoma: Both Hodgkin's and non-Hodgkin's lymphoma can present with axillary lymphadenopathy, although it's less common than breast cancer.
- Tuberculosis: Although less common in some regions, tuberculosis can cause lymphadenopathy in any location, including the axilla.
Do Not Miss Diagnoses
- Lymphoma (again, due to its potential severity): Despite being mentioned earlier, it's crucial to reiterate the importance of not missing a diagnosis of lymphoma due to its significant implications on patient outcomes.
- Metastatic Malignancy from Other Sites: Other cancers, such as lung, melanoma, or gastrointestinal cancers, can metastasize to the axillary lymph nodes, making a thorough investigation crucial.
- Sarcoidosis: This autoimmune disease can cause lymphadenopathy and, although rare, missing the diagnosis could lead to unnecessary morbidity.
Rare Diagnoses
- Kikuchi-Fujimoto Disease: A rare, self-limiting condition that causes lymphadenopathy, most commonly in the cervical region but can also affect axillary nodes.
- Kimura Disease: A chronic inflammatory disorder that can cause lymphadenopathy and eosinophilia, more common in Asian males.
- Castleman Disease: A rare disorder that can cause lymphadenopathy, often presenting with systemic symptoms, and can be associated with HIV infection or other conditions.
Each of these diagnoses has a unique set of clinical features, laboratory findings, and imaging characteristics that can help guide the diagnostic process. A thorough history, physical examination, and appropriate diagnostic tests are essential for determining the underlying cause of axillary lymphadenopathy.