Outcome of nonneoplastic pituitary cysts during conservative monitoring and after surgery-a SwissPit study.

Background: Nonneoplastic cysts of the pituitary are common incidental findings; however, best management remains controversial as they are often asymptomatic but eventually may cause symptoms. The aims of this study are to describe the course of conservative and surgical approaches, to assess timing and results of surgery, and to identify predictors for growth.

Methods: This retrospective study reviewed medical records from the Swiss Pituitary registry. Fifty patients (68% females; median 44 years old) fulfilled the criteria for inclusion. Three cohorts were defined: a conservative group (n = 28), a group who initially needed surgery (n = 18), and a group who had surgery during follow-up (n = 4). Transsphenoidal cyst evacuation was used in 95%; 68% had intraoperative MRI. All patients had standardized neuroradiological, endocrinological, and ophthalmological follow-up (mean 44 (7-151) months).

Results: Conservative follow-up of 30 (6-120) months showed cyst growth in 16% (4%/year) and spontaneous shrinkage in 19% (8%/year). Cyst-volumes changed - 0.95 to 1.45 cm per year. The probability of needing surgery was 5% per year. Larger cysts (> 1.4 cm) and T1-hypo-/T2-hyper cyst contents were associated with higher probability for growth. Postoperatively, no remnant was seen in 82% during a follow-up of 53 months. Visual field deficiencies improved in 83%. Hypopituitarism recovered in up to 88%. But for a smaller complication rate, the outcome was not influenced by the use of the intraoperative MRI.

Conclusions: Asymptomatic nonneoplastic pituitary cysts may be monitored; many lesions may shrink with time. Larger or T1-hypo-/T2-hyper cysts have higher growth rates. If indicated, surgery for nonneoplastic sellar cysts is a safe and efficient.