Differential Diagnosis for Continued Left Foot Pain with a "Lump"
- Single Most Likely Diagnosis
- Plantar fasciitis or a plantar fibroma: The pain is localized, worsens with pressure, and is exacerbated by the absence of supportive insoles. These conditions are common causes of foot pain and lumps, especially in areas that bear significant weight and pressure.
- Other Likely Diagnoses
- Morton's neuroma: This condition involves a thickening of the tissue around the nerves leading to the toes, causing pain and a sensation of a lump, especially between the toes. It can be exacerbated by pressure from shoes and lack of proper foot support.
- Bursitis: Inflammation of the bursae (fluid-filled sacs that cushion bones, tendons, and muscles near joints) can cause pain and swelling, which might feel like a lump. This could be due to repetitive motion or pressure.
- Callus or corn: Thickened skin due to repeated pressure or friction can cause discomfort and might be perceived as a lump, especially if it becomes large enough to press on surrounding tissues.
- Do Not Miss Diagnoses
- Osteoid osteoma: A benign bone tumor that can cause severe pain, typically worse at night and relieved by nonsteroidal anti-inflammatory drugs (NSAIDs). Although rare, missing this diagnosis could lead to prolonged pain and potential complications.
- Ewing's sarcoma or other bone cancers: Although extremely rare, these conditions can present with localized pain and swelling. Early detection is crucial for effective treatment.
- Infection (e.g., abscess, osteomyelitis): Infections can cause localized pain, swelling, and sometimes a palpable mass. These conditions require prompt medical attention to prevent serious complications.
- Rare Diagnoses
- Plantar keratoderma: A rare condition characterized by thickening of the skin on the soles of the feet, which can cause pain and discomfort.
- Foreign body reaction: If a foreign object (like a splinter) is embedded in the foot, it can cause localized pain, swelling, and sometimes a palpable lump.
- Tarsal tunnel syndrome: Compression of the posterior tibial nerve can cause pain, numbness, and tingling in the foot, which might be perceived as a lump due to the associated swelling.