What is the main characteristic of an empty sella syndrome?

Empty sella syndrome is characterized primarily by a phenomenon where the sella turcica, the bony structure that houses the pituitary gland, appears to be empty on imaging, typically an MRI. This condition often leads to decreased pituitary function, or hypopituitarism, due to the pituitary itself being compressed or flattened against the bony sella or due to actual loss of pituitary tissue.

In empty sella syndrome, the pituitary gland may not effectively produce hormones, leading to various endocrinological deficiencies. For instance, patients may exhibit signs of reduced secretion of key hormones such as ACTH, TSH, and LH/FSH, which are crucial for adrenal, thyroid, and gonadal function respectively. This hormone deficiency aligns with the observed clinical manifestations, including fatigue, changes in weight, and potential reproductive challenges.

Other options such as the presence of ovarian cysts, increased adrenal hormones, or hyperprolactinemia do not accurately capture the main feature of empty sella syndrome. The condition is primarily associated with changes in the pituitary gland's functional output rather than with other hormonal imbalances or structural changes in the ovaries. Thus, the decreased pituitary function serves as the defining characteristic of this syndrome