Article
Intraoperative ultrasound-directed resection of MRI-negative microadenoma in Cushing's disease (CD)
Ultraschall-unterstützte Resektion MRT-negativer Mikroadenome bei M. Cushing
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Published: | April 11, 2007 |
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Objective: In 40% of cases with CD preoperative MRI fails to detect a pituitary tumor. Intraoperative transsphenoidal ultrasound (US) identified microadenomas in CD as hyperechoic structures in 72%. Here, we report on the first 2 cases with detection of ACTH-secreting microadenomas using high-frequency US for intraoperative direct contact use.
Methods: Both cases presented with typical endocrinological findings for CD. In case one (f, 44 yrs) MRI revealed a cysic lesion entered by a vessel. Case 2 (f, 35 yrs) had previously undergone pituitary surgery elsewhere, with only temporary remission of hypercortisolism. Pre- and postoperative MRI was negative.
During direct transnasal microsurgical pituitary surgery an end fire US-probe (UST-534, ALOKA, Wallington, CT: B-mode frequency range 7.5-13 Mhz, field opf view 5 mm) was introduced after bony opening of the sella turcica. The gland was scanned sagittally and axially in direct contact to the pituitary capsule using 12 and 13 Mhz, respectively.
Results: In both cases US identified the adenomas as hyperechoic masses, which corresponded to the surgical findings. The neurohypophysis was hypoechoic compared to the anterior lobe. In the first case,the peritumorous cyst was seen as a hypoechoic structure, the adjacent vessel was identified by Doppler mode US. In case 2, the tumor was identified as a dumb-bell shaped structure on both sides of the intrapituitary scar. Surgically induced remission of hypercortisolism was verified by detection of an early decline of serum cortisol to subnormal levels.
Conclusions: Intraoperative scanning of the pituitary gland with high-frequency US probes in direct contact to the pituitary capsule enables the surgeon to identify intrapituitary anatomy and pathologies. This makes it possible to avoid extensive exploration of the gland in MRI-negative cases.