Congenital indifference to pain: an illustrated case report and literature review.

Congenital indifference to pain is a rare and debilitating congenital disease. Individuals with the disorder may have one or a combination of sensory or autonomic deficits, which can range from lack of mechanical nociception, diminished ability to detect heat and cool stimulation, to the devastating and fatal form which includes autonomic dysfunction. It is important for radiologists to be able to recognize the radiographic presentations of this rare disorder, as delay in diagnosis can lead to extensive and sometimes unnecessary workup. We present a case of congenital indifference to pain initially interpreted as a mass of the distal femur.