Differential Diagnosis for Ankle Bump
The patient presents with a history of left ankle fracture with surgery and a small, tender bump on the Achilles tendon. Here's a categorized differential diagnosis:
- Single Most Likely Diagnosis
- Achilles Tendinosis or Tendinitis: Given the patient's history of ankle fracture and surgery, along with the location and tenderness of the bump, Achilles tendinosis or tendinitis is a common complication. The chronic stress and possible altered biomechanics post-surgery could contribute to tendon inflammation or degeneration.
- Other Likely Diagnoses
- Haglund's Deformity: This condition involves a bony enlargement on the back of the heel that can irritate the Achilles tendon, leading to pain and swelling. It's plausible given the bump's location and the patient's history of ankle issues.
- Achilles Tendon Nodule: Nodules can form on the Achilles tendon due to chronic inflammation or injury, which could be related to the patient's past ankle fracture and surgery.
- Bursitis: Specifically, retrocalcaneal bursitis could cause a painful bump near the Achilles tendon insertion, though it typically presents with more swelling and erythema than described.
- Do Not Miss Diagnoses
- Soft Tissue Sarcoma: Although rare, any unexplained mass, especially one that is growing or persistent, warrants consideration of a soft tissue tumor. Early detection is crucial for treatment outcomes.
- Infection: Despite the lack of erythema, an infectious process (e.g., abscess or infected bursa) could present with localized pain and swelling. This is particularly concerning in a post-surgical patient.
- Rare Diagnoses
- Xanthoma: These are rare, benign growths that can occur on tendons, including the Achilles, often associated with lipid disorders.
- Giant Cell Tumor of the Tendon Sheath: A rare, benign tumor that could present as a nodule near the Achilles tendon, though it's more commonly associated with the fingers.
- Achilles Tendon Rupture: While typically presenting acutely, a partial rupture could potentially cause a palpable defect or bump, especially if chronic.
Each diagnosis should be considered in the context of the patient's full history, physical examination, and potentially, diagnostic imaging or laboratory tests to determine the most appropriate diagnosis and treatment plan.