The remission rate of Cushing’s disease in patients after neurosurgery varies from 59 to 94%, while the recurrence rate is 3 to 46%. Aim — to evaluate the five-year outcome in neurosurgery patients with Cushing’s disease (CD), depending on preoperative MRI-based identification of pituitary adenoma. Material and methods. The study included 105 neurosurgery patients with histologically confirmed CD. CD remission was confirmed by the development of adrenal insufficiency and/or normalization of serum cortisol and 24-hour urinary free cortisol (24h UFC) levels, as well as by clinical remission. Results. Pituitary adenoma was not visualized by gadolinium MRI in 35 cases. The size of visualized pituitary adenoma varied from 0.3 to 29 mm. After first neurosurgery, remission was achieved in 87 (82.8%) patients. After second neurosurgery, remission occurred in 12 patients. Radiation therapy was conducted in 24 patients. Six patients had bilateral adrenalectomy. Two patients died during remission: one patient died from stroke two years after neurosurgery, and the other patient died due to surgery complications. During five-year follow-up after neurosurgery, remission continued in 76 (72.8%) patients, including 27 (77%) of 35 patients without MRI-detected adenoma and 49 (70%) of 70 patients with MRI-detected pituitary adenoma, p=0.15. Sixty-six patients developed recurrence, and 14 patients had active hypercortisolism. Conclusion. There was no correlation between the rate of preoperative MRI-based detection of pituitary adenoma and the rate of remission in neurosurgery patients with Cushing’s disease during the five year follow-up. The size of pituitary adenoma was a risk factor for adenoma recurrence.

Background. Regardless of improvements in MRI, up to 20% of ACTH-secreting pituitary tumors are only identified at surgical exploration. Aim. Тo estimate whether there is any difference in blood vessels and the subsequent ability to uptake contrast agent in visualized microadenoma as compared to non-visualized on MRI ACTH-secreting pituitary tumors.Material and methods. Retrospective evaluation of ACTH-positive pituitary tumors from patients with Cushing’s disease (n=39) with either non-visualized pituitary tumor on MRI (n=17) or pituitary tumor less then 25 mm (n=22). MRI was performed using Siemens Magnetom Harmony 1.0T with gadolinium. Selected tumors were stained with anty-СD34 antibody (clone QBEnd/10, RTU, Leica) and anty-D2-40 antibody (clone D2-40, RTU, Dako). We evaluated the microvessels density and measured the diameter of larger and smaller vessel.Results. The microvessels density were not different in subject with visualized [123 (77; 136)] and non-visualized [112 (110,0; 126,5)] pituitary adenomas as well as number of slit-shaped vessels [32 (5; 50) in visualized vs 25 (5; 50) in non-visualized pituitary adenoma]. The diameter of these vessels also did not differ: the diameter of the largest vessels in patients without visualization 53 µm (32,5; 63,5) vs 33 µm (30,0; 51,5) the average diameter of the blood vessels 15 µm (14,5—26,0) against 13 µm (12; 14).Conclusions. The diameter and microvessels density in ACTH-producing pituitary adenoma does not affect the visualization of adenoma on MRI in patients with Cushing ‘s disease.