Differential Diagnosis for 53 F with Pain Underneath Collarbone

The patient presents with pain underneath the collarbone, swelling, and difficulty lifting her arm without a history of injury. The following differential diagnoses are considered:

• Single Most Likely Diagnosis
  • Subacromial Bursitis: This condition involves inflammation of the bursa that cushions the rotator cuff tendons, leading to pain and swelling in the shoulder region, especially when lifting the arm. The symptoms and presentation are consistent with this diagnosis.
• Other Likely Diagnoses
  • Rotator Cuff Tendinitis: Inflammation of the tendons of the rotator cuff muscles can cause pain and weakness in the shoulder, especially with arm movements.
  • Adhesive Capsulitis (Frozen Shoulder): Characterized by stiffness and pain in the shoulder joint, it can lead to difficulty moving the arm.
  • Costoclavicular Syndrome: Compression of the neurovascular bundle between the clavicle and the first rib can cause pain and swelling in the area underneath the collarbone.
• Do Not Miss Diagnoses
  • Thoracic Outlet Syndrome: Compression of the nerves and/or blood vessels that pass into the thoracic outlet (the space between your collarbone and first rib) can cause pain in the shoulder and arm, and if missed, could lead to serious complications like nerve damage.
  • Lymphoma or Other Malignancies: Although less common, swelling and pain in the supraclavicular area can be a sign of lymphoma or metastatic disease, which would be critical to diagnose early.
  • Deep Vein Thrombosis (DVT): While less likely given the location of pain, DVT in the upper extremity could present with swelling and pain, and is a potentially life-threatening condition if not treated promptly.
• Rare Diagnoses
  • Pancoast Tumor: A type of lung cancer located at the top of the lung that can cause shoulder pain due to invasion of the brachial plexus or ribs.
  • Osteonecrosis of the Clavicle: A rare condition where the bone tissue of the clavicle dies due to lack of blood supply, leading to pain and swelling.

Each diagnosis is considered based on the patient's symptoms of pain underneath the collarbone, swelling, and difficulty lifting her arm. The justification for each includes the typical presentation and potential for the condition to cause the symptoms described. Further evaluation, including imaging studies and possibly a thorough neurological examination, would be necessary to narrow down the differential diagnosis and guide treatment.