Young, William F.

SummaryPurposeThe distinction between corticotropin (ACTH)‐producing pituitary adenomas and occult ectopic ACTH neoplasms is a challenge and frequently complicated by the detection of nonfunctioning pituitary adenomas on dynamic magnetic resonance imaging (DMRI). Herein, we explored quantitative differences in DMRI measures from ACTH‐producing pituitary adenomas.Materials and methodsFifty‐five patients with pathology confirmed ACTH‐producing and 44 with nonfunctioning pituitary adenomas were analysed in this retrospective pilot study. The intensities of adenomas and of adjacent pituitary tissue were measured by drawing a region of interest. Time–intensity curves were then constructed, and quantitative analysis included: enhancement time, enhancement peak and prepeak slope (PPS). Multivariable logistic analysis and receiver operating characteristic curves (ROC) were used to evaluate the parameters.ResultsQuantitative analysis showed that tumour PPS in ACTH‐producing adenomas was markedly lower than that in nonfunctioning adenomas (P = 0·0042) and that the PPS of the adjacent pituitary gland was not different (P = 0·2441). The PPS was >3·0 in 59·1% of nonfunctioning adenomas and ≤3·0 in 69·1% of ACTH‐producing adenomas (P = 0·0049). Logistic analysis revealed lower tumour PPS levels (P = 0·0123, OR 1·24, 95% CI: 1·05–1·52) were associated with ACTH‐producing adenomas. The optimal PPS cut‐off determined by ROC analysis was 2·89, with a sensitivity of 69% and specificity of 70%. No significant difference was found between the two groups in enhancement time or enhancement peak.ConclusionEnhancement parameters in DMRI can help distinguishing ACTH producing from nonfunctioning pituitary adenomas, which could be useful in the differential diagnosis between ACTH‐producing pituitary adenomas and ectopic ACTH syndrome complicated with nonfunctioning pituitary adenoma.

We describe four cases of symptomatic pneumocranium, a rare, potentially life-threatening complication of transsphenoidal pituitary surgery. Symptomatic pneumocranium manifested as impaired mental status, headaches, and grand mal seizures, early in the postoperative course after transsphenoidal pituitary surgery. Furthermore, a Cushing response, including systemic hypertension and bradycardia (secondary to intracranial hypertension) was seen, which has not been previously described in association with symptomatic pneumocranium. We describe a previously unreported risk factor for tension pneumocranium, untreated obstructive sleep apnea. Other factors predisposing to tension pneumocranium in our patients included: cerebrospinal fluid leaks, postoperative positive-pressure mask ventilation, large pituitary tumors, and intraoperative lumbar drainage catheters. Surgical drainage of the pneumocranium and repair of any coexistent cerebrospinal fluid leak markedly improved neurologic status. Symptomatic pneumocranium occurring early in the postoperative course after transsphenoidal pituitary surgery is rare, but prompt recognition and treatment of this condition can be life-saving.