227. Pituitary Stalk Biopsy For Germinoma: Single-Institution Review of Success Rates and Outcomes Of Minimally Invasive vs. Open Biopsies

Authors: Katie Pricola Fehnel, MD; Emily Day, BS (Boston, MA)


Germinomas is a rare tumor that often presents as isolated pituitary stalk thickening. There is limited literature on the role for stalk biopsy. We seek to review a single center series of open vs. endoscopic biopsy for isolated pituitary stalk thickening and to measure the diagnostic success, length of surgery, length of stay, and operative morbidity of the two approaches.


Patients were identified in our institutional surgical database. Using search terms “pituitary,” “germinoma,” or “diabetes insipidus” 122 patients were identified over a 20 year period. Patients were excluded based on diagnosis (e.g. craniopharyngioma, adenoma, glioma, other), location (pineal), and absent clinical data or preoperative imaging. Ten patients met criteria and were classified as open craniotomy vs. minimally invasive (transphenoidal or endoscopic). Age, endocrine status, length of surgery, estimated blood loss (EBL), surgical morbidity, length of ICU stay, total length of stay, and diagnostic yield were included. An independent samples t-test was performed to detect significant differences between groups among variables.


Ten patients requiring biopsy for pituitary stalk thickening were identified- 4 craniotomy (age 3.98-9.46years) and 6 minimally invasive (age 6.88-15.93years). Between the two groups there was a significant difference in age at surgery (p=0.031) and a statistically significant decrease in operative time (p = 0.006) and overall length of stay (0.007) for the minimally invasive cohort. Though not statistically significant, minimally invasive biopsies yielded higher rates of successful diagnosis at 83% vs. 25% in the open craniotomy (p = 0.077). There was no significant difference in endocrine status, operative morbidity, EBL or ICU stay.


Minimally invasive biopsy yielded higher rates of diagnostic success with shorter anesthesia times and decreased length of stay. Transphenoidal biopsy should be considered for patients for whom this is feasible even in the setting of isolated stalk thickening.