Evaluation of the thyroid characteristics of patients with growth hormone-secreting adenomas

Venous blood was collected from all participants after they had fasted for 8–10 h. Levels of GH, IGF-1, and other pituitary endocrine hormones were measured using a chemiluminescent immunoassay system. Conventional and enhanced MRI scans of the pituitary gland were performed on all patients. The steps of the procedure were as described in our previous studies [11].

Thyroid ultrasonography was performed by a practitioner using an iU22 xMatrix-DS Ultrasound system (PHILIPS, 795112) with a 3–12-MHz linear transducer. The thyroid volume was calculated using the volume formula for an ellipsoid model (π/6 × width × length × thickness). The sum of the volume of each thyroid lobe and isthmus was defined as the total thyroid volume [7]. Goiter was defined as a thyroid volume greater than 12.6 cm³ in women and 17.1 cm³ in men. After determining the thyroid volume, the patients were classified into the normal, diffuse goiter, and nodular goiter groups according to the thyroid morphology.

FNAB was performed by a practitioner on patients with nodule volume exceeding 1 cm³ or a node with two or more of diverse signals: 1) hypoechoic nodules, 2) hazy nodular border, 3) uneven internal echo, 4) abundant blood flow in the middle of the nodule, 5) multifocal strong echo, and 6) tophaceous calcification. The cytopathological results were analyzed by the same pathologist according to the Bethesda system [12].

Statistical analyses were performed using IBM SPSS Statistics for Windows, version 19.0, and the results were expressed as medians (minimum-maximum). Pairwise comparisons were conducted using Wilcoxon rank-sum tests. f: Fisher’ exact test: 1) chi-square tests for n < 40 and 1 ≤ T < 5, 2) Yates’ chi-square test for n ≥ 40 and T ≥ 5, and 3) Fisher’s exact probability tests for n < 40 and T < 1. P-values < 0.05 were considered statistically significant.

Figure 2 shows a representative pituitary adenoma in MRI showing an expanded sella with a pituitary adenoma inside. The histopathological morphology of thyroid disorders detected by hematoxylin and eosin staining is shown in Fig. 3. The pathological manifestations of nodular goiter were as follows: part of the follicular epithelium presented with columnar or papillary-like hyperplasia, formation of small follicles, part of the epithelium visible as old or atrophic, colloidal storage, interstitial fibrous tissue hyperplasia, and interval wrapping forming the different sizes of nodular lesions. The pathological manifestations of thyroid cancer were as follows: large numbers of nipple branches; vascular interstitial fibrosis at the center of the nipple and visible granules; nipple epithelium appearing as single or multi-layer cancer cells with varying degrees of differentiation; visible nuclear chromatin appearing as less, frosted glass or transparent; and lack of nucleoli. The morphological characteristics were analyzed by thyroid ultrasonography assay (Fig. 4). The characteristics of diffuse goiter, nodular goiter, and papillary thyroid cancer are shown in Table 1. The characteristics of diffuse goiter were a slightly thicker thyroid parenchyma on echo imaging, lack of lesions, and increased blood supply. The characteristics of nodular goiter included an irregular thyroid gland, uneven envelope, uneven internal echo, and normal blood supply. The thyroid gland presented with multiple nodules, mixed echoes, partial nodule liquefaction, partial nodules with coarse calcification, clear boundaries, and limited blood supply. The characteristics of papillary thyroid cancer were a slightly thicker thyroid parenchyma echo, low echogenicity, presence of many small calcified nodules, unclear border, and abundant peripheral blood supply. The incidence of thyroid disorders is shown in Table 2. The prevalence of thyroid disease was higher in the GH-secreting adenoma group than in the NF pituitary adenoma group (79.1% vs. 34.3%, P < 0.05). Among the 76 patients with thyroid disease, six of eight patients who presented with diffuse thyroid and 44 of the 65 patients with nodular goiter had GH-secreting adenomas. Notably, all three patients with thyroid carcinoma had GH-secreting adenomas. This result indicates the potential strong correlation between GH-secreting adenoma and aggressive thyroid disorders. Additionally, the TSH and FT3 levels were significantly increased, whereas the FT4 level had no significant change in the GH-secreting adenoma group compared with that in the NF pituitary adenoma group (Fig. 5).

The characteristics of the thyroid nodules in patients with GH-secreting and NF pituitary adenomas are shown in Table 3. Among those with GH-secreting adenomas, the proportion of patients with multiple thyroid nodules was significantly higher than that of patients with single thyroid nodules. In addition, the proportion of patients with GH-secreting hormone adenomas who presented with multiple thyroid nodules (80.9%) was significantly higher than that of patients with NF pituitary adenomas (42.9%). The proportion of patients with hypoechoic, isoechoic, heterogeneous, and vascular lesions was significantly higher in the GH-secreting adenoma group than in the NF pituitary adenoma group.

Overall, 21 patients underwent transsphenoidal pituitary adenoma resection and were followed up for 1 year. Among them, 12 cases were cured, while nine cases were not cured. The morphological characteristics were analyzed by thyroid ultrasonography assay, the results of which are shown in Table 4. The number of thyroid nodules did not significantly change before and after surgery in the cured and non-cured groups. In addition, the number of patients with cystic nodules was significantly increased, while the number of solid nodules, heterogeneous nodules, and vascular thyroid nodules after surgery significantly decreased compared with those before surgery in the cured group. The characteristics of the thyroid nodules did not change significantly after surgery compared with those before surgery in the non-cured group.