gms | German Medical Science

Objective: The diagnosis of Cushing's disease (CD) is based on endocrinological parameters, with no single test being specific. MRI may fail to detect a pituitary tumor. Therefore, pituitary exploration during transsphenoidal surgery may be necessary. We report on our consecutive series of 50 patients who underwent transsphenoidal surgery under the diagnosis of CD.

Method: Out of 50 patients (36 f, 14 m, age 20–71 years, mean FU 40 mo.) with typical findings for CD (42 primary cases), in 30 cases microadenomas were suspected or identified by MRI, in 5 cases macroadenomas were visible, and in 15 cases MRI (30%) was negative. Inferior petrosal sinus sampling (IPSS) was performed in 13 cases. A total of 59 microsurgical transsphenoidal procedures were performed using neuronavigation (56 × MRI, 1 × CT) and intraoperative ultrasound (US, N = 47). Decline of serum-cortisol was monitored to assess early remission of CD.

Results: In 25 out of 37 cases (68%) with proven microadenomas US identified the tumors as hyperechoic masses, 3 were negative, 5 false positive, and 6 were questionable. In the 7 out of 15 cases with false negative MRI, intraoperative ultrasound identified the adenomas correctly. In 44 out of 50 patients postoperative decline of serum cortisol to subnormal levels revealed remission of CD (overall remission rate 88 %). With proven microadenomas remission rate was 95.2% (40 out of 42), with successful early reoperations in 2 cases (remission rate 100%). In 2 cases extensive pituitary exploration was negative (4%). After 57 operations subnormal cortisol levels were detected as early as the first postoperative morning in 38 cases (67%). In 40 out of 48 cases evaluated so far, anterior pituitary function was intact at follow-up (83%), 5 were unchanged (10%) and 3 were deteriorated (6%, all after reoperations). Out of 46 patients with postoperative remission of CD 4 developed recurrent hypercortisolism (9%), including 2 out of 39 primary operations (recurrence rate 5%).

Conclusions: The diagnosis of CD remains to be based purely on endocrinological data. Only in equivocal results IPSS is indicated. MRI may be misleading or negative, is always unspecific. In MRI-negative cases, intraoperative ultrasound may identify the adenoma and thus prevent harmful exploration of the gland. Transsphenoidal surgery for CD should be performed only by specialized pituitary surgeons.