Differential Diagnosis for a 15-year-old Female with a Lump in the Axillae
Single Most Likely Diagnosis
- Lymphadenopathy due to benign causes: This is the most likely diagnosis given the absence of erythema or fever, suggesting a non-infectious etiology. Benign lymphadenopathy can be caused by various factors, including viral infections, allergic reactions, or physiological responses to stress or hormonal changes.
Other Likely Diagnoses
- Axillary abscess or hidradenitis suppurativa: Although the patient does not have erythema or fever, these conditions can sometimes present without significant inflammation. Hidradenitis suppurativa is a chronic skin condition that can cause lumps and abscesses in the axillae.
- Lipoma or other benign tumors: Benign tumors such as lipomas can occur in the axillae and present as a lump.
- Cat scratch disease: This is a bacterial infection caused by Bartonella henselae, typically transmitted through cat scratches. It can cause lymphadenopathy, often in the axillae.
Do Not Miss Diagnoses
- Breast cancer: Although extremely rare in teenagers, breast cancer must be considered, especially if the lump is fixed, hard, or associated with other symptoms like nipple discharge.
- Lymphoma: Lymphomas, such as Hodgkin's or non-Hodgkin's lymphoma, can present with lymphadenopathy in the axillae. Given the potential severity of these conditions, they should not be missed.
- Tuberculosis: TB can cause lymphadenopathy, and although less common in the axillae, it's a critical diagnosis not to miss due to its public health implications and the need for specific treatment.
Rare Diagnoses
- Sarcomas: Soft tissue sarcomas are rare tumors that can occur in the axillae, presenting as a lump.
- Metastatic disease: Metastasis to the axillary lymph nodes from other cancers is rare in teenagers but could be considered in the differential diagnosis, especially if there's a known primary malignancy.
- Granulomatous diseases: Conditions like sarcoidosis can cause lymphadenopathy, although they are less common in the axillae and would typically be associated with other systemic symptoms.