A comparative study of functioning and non-functioning pituitary adenomas

Abstract

Pituitary tumors commonly cause visual impairment and the degree of impairment can depend on the size, location, and type of the tumor. However, no studies have been made regarding the differences caused by functioning pituitary adenoma (FPA) and non-functioning pituitary adenoma (NFPA). We aimed to investigate the relationship between clinical characteristics and visual impairment in patients with FPA and NFPA.This case series study included 73 pituitary adenoma patients. All patients underwent ophthalmic evaluations, and we retrospectively reviewed their medical records. Tumor types were confirmed by histological analysis, and the tumor volume was calculated. Magnetic resonance imaging was used to determine the tumor diameter. The observation indices of the two groups were compared. The correlation between the visual field and tumor volume was analysed using scatter plots.We enrolled 30 patients in the FPA group and 43 in the NFPA group. The first symptoms presented in the eyes in 23% of FPA patients and 41.9% of NFPA patients. The best-corrected visual acuity of the FPA group was better than that of the NFPA group, and 34 (56.7%) and 73 (84.9%) eyes in these groups had visual field defects, respectively. The visual field defects of the FPA patients were lighter than those of the NFPA patients. Except for the anteroposterior diameter, there were no differences in the other parameters of tumor diameter between the groups. The tumor volume of the FPA group was smaller than that of the NFPA group. The tumor size was positively correlated with the mean deviation and negatively correlated with the mean sensitivity in both groups.There was a longer delay between the onset of signs and symptoms and treatment in the FPA group than in the NFPA group. Future studies should focus on visual field defects caused by FPA and NFPA.

Figure 1

Visual field and MRI of four patients with pituitary adenoma. Top-left: Case 1. A 53-year-old woman with NFPA at diagnosis. Visual field: bilateral temporal hemianopsia breaking through the vertical midline. Contrast-enhanced MRI shows that the pituitary dumbbell-shaped mass with a clear boundary is significantly enhanced, with a size of 2.7 × 2.6 × 4.0 cm. The mass protrudes to the sella and compresses the optic chiasma. Top-right: Case 2. A 70-year-old man with NFPA at diagnosis. Visual field: bilateral superior temporal quadrant visual field defect and breakthrough to the inferior temporal region. Contrast-enhanced MRI shows that the tumor is significantly enhanced, with a size of 1.9 × 1.8 × 2.5 cm and a clear boundary. The pituitary stalk is shifted to the left, and the optic chiasma is displaced upwards. Bottom-left: Case 3. A 47-year-old man with FPA (parasellar prolactinoma) at diagnosis. Visual field: nasal hemianopsia in the right eye and a quadrant visual field defect in the left eye. Contrast-enhanced MRI shows that the tumor is significantly enhanced, with a size of 2.0 × 2.7 × 3.0 cm and an irregular boundary. The pituitary stalk is shifted to the left, and the anterior part of the optic chiasma is obviously elevated on the right side. Bottom-right: Case 4. A 67-year-old man with NFPA at diagnosis. Visual field: superior hemianopsia in the right eye and a superior local defect in the left eye. Contrast-enhanced MRI shows that the tumor is 1.8 × 1.7 × 1.9 cm, and the left optic chiasma is compressed and displaced upwards. MRI = magnetic resonance imaging, FPA = functioning pituitary adenoma, NFPA = non-functioning pituitary adenoma.

Figure 2

Correlation between the tumor size and visual field parameters. Top-left: Correlation between the mean deviation (MD) and tumor volume in patients in the FPA group. Pearson correlation coefficient = 0.515, P < .001. Top-right: Correlation between the mean sensitivity (MS) and tumor volume in patients of the FPA group. Pearson correlation coefficient = −0.512, P < .001. Bottom-left: Correlation between the MD and tumor volume in patients of the NFPA group. Pearson correlation coefficient = 0.446, P < .001. Bottom-right: Correlation between the MS and tumor volume in patients of the NFPA group. Pearson correlation coefficient = −0.437, P < .001. FPA = functioning pituitary adenoma, NFPA = non-functioning pituitary adenoma.