Lesson of the month 2: Cauda equina in Cushing's syndrome.

We present the case of a 34-year old woman who initially presented with obesity and back pain. She was eventually diagnosed with Cushing's syndrome secondary to an adrenocortical carcinoma that had metastasised to her spine, causing cauda equina compression. The delays in reaching the correct diagnosis caused significant morbidity and exemplify the pitfalls of premature closing, a common cognitive error in diagnostic reasoning.