Which of the following conditions would require massage to be avoided?

Massage should be avoided in the case of thrombophlebitis due to the potential for serious complications. Thrombophlebitis involves inflammation of a vein that may also be associated with a blood clot. Applying massage to an area affected by this condition could dislodge the clot, leading to potentially life-threatening conditions such as a pulmonary embolism if the clot travels to the lungs.

In contrast, conditions like tension headaches, mild muscle soreness, and stress-related issues generally do not present the same risks. Tension headaches can often be alleviated with appropriate massage techniques. Mild muscle soreness is usually a sign of overuse and can benefit from massage to promote circulation and healing. Similarly, massage is a common technique employed to reduce stress and promote relaxation. Therefore, thrombophlebitis is unique among these conditions as it poses a specific and significant risk that necessitates avoiding massage therapy altogether.