Immunochistochemical characteristics of blood vessels in non-visualized and visualized on MRI pituitary adenoma in patients with Cushing’s disease

Backgraund. Regardless of improvements in MRI, up to 20% of ACTH-secreting pituitary tumors are only identified at surgical exploration.

Aim: to 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.

Materials 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.