A 43-year-old man comes to the physician with pain in his left leg. He has a background of a left below-the-knee amputation 10 years ago. He reports that since the amputation he has always been “aware” of his left foot and had the feeling that it was still there. With time, it felt that his foot was moving proximally, and additionally, he developed pain and “burning” at the stump of his left leg. The pain does not change with position of his leg, topical treatments or medications. He is most likely suffering from which of the following syndromes?

**Core Concept**
Phantom limb syndrome is a complex phenomenon where patients experience sensations, such as pain, touch, or movement, in a limb that is no longer present. This condition arises due to maladaptive plasticity of the central nervous system, particularly in the somatosensory cortex, where the brain continues to process sensory input from the missing limb.

**Why the Correct Answer is Right**
In this case, the patient's symptoms of pain, burning, and the feeling of his foot moving proximally are characteristic of phantom limb syndrome. This condition often develops after amputation and can be resistant to treatment. The patient's description of his sensations not changing with position, topical treatments, or medications further supports this diagnosis. The somatosensory cortex, which processes sensory information from the body, continues to receive input from the missing limb, resulting in these unusual sensations.

**Why Each Wrong Option is Incorrect**
**Option A:** Stump pain is a common complication after amputation, but it typically responds to treatment and is not accompanied by the same level of complex sensations as phantom limb syndrome.
**Option B:** Neuroma formation is a possible complication after amputation, but it would typically be accompanied by a palpable mass or a specific trigger point for pain, which is not described in this case.
**Option C:** Complex regional pain syndrome (CRPS) is a condition characterized by chronic pain and inflammation in response to injury or trauma, but it typically involves changes in skin temperature, color, or swelling, which are not mentioned in this case.

**Clinical Pearl / High-Yield Fact**
Phantom limb syndrome is a common complication after amputation, affecting up to 80% of patients. It is essential to recognize this condition and manage it with a multidisciplinary approach, including pain management, physical therapy, and psychological support.

**Correct Answer: C. Phantom limb syndrome.**

✓ Correct Answer: C. Phantom limb pain