Differential Diagnosis for a Lump/Mass in the Arm Pit
Single Most Likely Diagnosis
- Lipoma: A benign tumor composed of fat tissue, which is common in the axillary region and can grow in size over time.
- Cyst: Such as an epidermoid cyst or sebaceous cyst, which can occur in the axilla and may increase in size.
Other Likely Diagnoses
- Lymphadenopathy: Enlargement of lymph nodes in the axilla, which can be due to infection, inflammation, or other benign conditions.
- Abscess: A collection of pus in the axilla, often caused by bacterial infection, which can present as a growing lump.
- Folliculitis or Furuncle: Inflammation of the hair follicles or a boil, which can occur in the axilla and may appear as a growing mass.
- Hidradenitis Suppurativa: A chronic skin condition characterized by recurrent abscesses and nodules in the apocrine-gland-bearing areas, such as the axilla.
Do Not Miss Diagnoses
- Breast Cancer: Although less common, breast cancer can metastasize to the axillary lymph nodes, presenting as a lump in the arm pit.
- Lymphoma: A type of cancer that affects the immune system and can cause lymphadenopathy in the axilla.
- Soft Tissue Sarcoma: A rare type of cancer that can occur in the axilla, presenting as a growing mass.
Rare Diagnoses
- Tuberculosis: A bacterial infection that can cause lymphadenopathy in the axilla, although this is relatively rare in many parts of the world.
- Cat-Scratch Disease: An infection caused by Bartonella henselae, which can lead to lymphadenopathy, including in the axilla.
- Actinomycosis: A rare bacterial infection that can cause abscesses or masses in the axilla.