USMLE (United States Medical Licensing Examination) Step 1 Practice Exam 2026 - Free USMLE Step 1 Practice Questions and Study Guide

Empty sella syndrome is characterized by a radiological finding where the sella turcica, which normally houses the pituitary gland, appears empty or partially filled with cerebrospinal fluid (CSF). The hallmark radiological feature is indeed the subarachnoid space extending into the sella turcica, giving the appearance that the pituitary gland is absent or flattened. This phenomenon occurs due to herniation of the CSF through the defect in the diaphragm sella, leading to the cistern-like space where the pituitary gland used to be.

Recognizing this radiologic characteristic is essential in diagnosing empty sella syndrome, particularly since patients may present with symptoms related to pituitary dysfunction, but the imaging reveals this distinctive appearance rather than an actual absence of the gland in all cases. Other possible findings with conditions that could mimic this syndrome might not demonstrate the specific extension of the subarachnoid space, emphasizing the importance of this particular radiological feature for proper identification.