Progress in the Pathogenesis, Diagnosis, and Treatment of TSH-Secreting Pituitary Neuroendocrine Tumor

Clinical characteristics and outcomes of patients with TSH-secreting pituitary adenoma and Graves' disease - a case report and systematic review

BACKGROUND

Coexistence of TSH-secreting pituitary adenoma (TSHoma) and Graves' disease (GD) is rare and complicates the management decision.

METHODS

We present a case of the co-existence of TSHoma and GD. In addition, we systematically searched articles describing TSHoma and GD in the same patient published until 20th March 2023, using Pubmed, Scopus and Embase.

CASE PRESENTATION

A 46-year-old man presented with symptoms of thyrotoxicosis. His thyroid function tests showed serum TSH 3.35 (reference range 0.3-4.2) mIU/L, FT3 19.7 (3.7-6.4) pmol/L, and FT4 68.9 (11-23.3) pmol/L. The serum TSH receptor antibody was 11.5 mIU/L (positive at ≥ 1.75 mIU/L). Pituitary magnetic resonance imaging showed macroadenoma compressing the optic chiasm. The patient underwent trans-sphenoidal resection of pituitary adenoma. Postoperatively, he remained on maintenance carbimazole and octreotide.

RESULTS

Fourteen articles comprising 15 patients were identified from the systemic search. A total of 16 patients (including the current case) were included in the systematic review. The mean (± SD) age at diagnosis was 41 ± 13.6 years. The majority were females (75%). The median (IQR) TSH was 1.95 (0.12-5.5) mIU/L, the median (IQR) free T3 was 11.7 (7.6-19.7) pmol/L and the median (IQR) free T4 level was 47.6 (33.3-64.4) pmol/L. Ten (76.9%) patients had positive TSH receptor antibody levels. 84.6% had pituitary macroadenoma. Pituitary surgery was performed in 12 (75%) patients. At the last follow-up, 4 (25%) patients had complete resolution of symptoms after pituitary surgery, 3 (18.7%) were on maintenance treatment with thionamides for GD, 1 (6.25%) on beta-blockers and 1 (6.25%) on somatostatin analog.

CONCLUSION

TSHoma and GD can co-exist, and it is essential to identify this rare association as it can significantly impact treatment strategies.

Metabolic Syndrome Components in Patients with Pituitary Adenoma

Pituitary adenomas are benign tumors of the anterior portion of the pituitary gland (adenohypophysis), representing the 25% of all the tumor alterations. Pituitary adenomas are classified by the type of hormone secreted, cellularity, size, and structural alterations by the hormonal segregation. The diagnosis consists on the histopathological identification of cell types and the image-guided by magnetic resonance or tomography; the treatment can be both pharmacological and surgical. Metabolic Syndrome is the set of clinical conditions that increase the risk of cardiovascular diseases with an estimated prevalence of 25% worldwide. The alterations of metabolic syndrome are obesity, hypertension, dyslipidemia, insulin resistance, and diabetes mellitus type II. Pituitary adenomas and metabolic syndrome have an important relationship, hormone-secreting by pituitary adenomas affects a myriad of signaling pathways, which allows a favorable environment for the appearance of the metabolic syndrome. Moreover, patients with pituitary adenomas are shown to have an improvement in metabolic parameters after the medical/surgical treatment. The objective of this review is to explore the possible mechanisms through which PAs contributes to MetSx.

A reference center study in thyrotropin-secreting pituitary adenomas: clinicopathological, therapeutic and long-term follow-up outcomes

PURPOSE

This study aims to analyze the clinicopathological features, diagnostic steps, and therapeutic results of TSHomas and to reveal the effective factors on remission.

METHODS

The clinical, radiological, and pathological features and surgical and endocrinological results of 41 TSHoma cases followed between 2005 and 2022 were retrospectively analyzed. The factors affecting the surgical cure were investigated by comparing the groups with and without remission.

RESULTS

A total of 41 patients (23 male,18 female) were included in the study and the mean age was 42 (31.5-49). Palpitation and headache were the most common complaints. The time from the onset of symptoms to diagnosis was 8 (3-20) months. There were 8 patients with a preoperative clinical and biochemical diagnosis of TSH + GH co-secretion. In the TRH stimulation test, a blunted TSH response was obtained in 18 patients (90.0%). Complete suppression could not be obtained in any of the patients who underwent the T3 suppression test. The median maximum tumor diameter was 19.0 mm (6.8-41). There was microadenoma in 4 (9.8%) patients and macroadenoma in 37 patients (92.8%). Remission was achieved in 31 (75.6%) of 40 patients who underwent endoscopic transsphenoidal surgery (eTSS). The Ki-67 labeling index was 2% (1.00-4.00) in the entire patient group. Preoperative use of antithyroid drugs appears to be significantly associated with surgical cure.

CONCLUSION

Diagnosis of TSHoma is still full of challenges and dynamic tests remain important. Recognition and good management of inappropriate TSH secretion states affect subsequent surgical outcomes.

[Thyrotropin-secreting pituitary adenomas: clinical features and results of treatment in 45 patients]

BACKGROUND

Thyrotropin-secreting pituitary adenomas (TSH-PA) are a rare cause of thyrotoxicosis and account for 0.5-2% of all pituitary adenomas. Taking into account the rarity of the disease, it is extremely important to analyze each case of TSH-PA.

AIM

To analyze the clinical characteristics and treatment outcomes of patients with TSH-PA, as well as to determine preoperative and early postoperative factors that predict long-term remission.

MATERIALS AND METHODS

In a single-center retrospective study we analyzed clinical signs, laboratory and instrumental studies, as well as the treatment outcomes of patients with TSH-PA from 2010 to 2023. Preoperative factors, as well as TSH level measured on day 3 postoperatively, were evaluated for their ability to predict long-term remission when comparing groups of patients with and without remission.

RESULTS

The study included 45 patients with TSH-PA (14 men, 31 women), with a median age of 45 years [30; 57]. The most common clinical manifestations of TSH-PA were: cardiac arrhythmia in 37 (82.2%) patients, thyroid pathology in 27 (60%), neurological disorders in 24 (53.35%). Most PAs were macroadenomas (n=35, 77.8%). Preoperatively, 28 (77.8%) patients received somatostatin analogs, and 20 (71.4%) patients were euthyroid at the time of surgery. Surgical treatment was performed in 36 (80%) patients, postoperative remission was achieved in 31 cases (86.1%). Administration of somatostatin analogues to patients with no remission/relapse after surgery lead to the remission in 100% of cases (4/4). A 1 mm increase in PA size raised the odds of recurrence/no remission by 1.15-fold,and PA invasion during surgery - by  5.129 fold. A TSH level on day 3 postoperatively above 0.391 mIU/L (AUC, 0.952; 95% CI 0.873-1.000; standard error 0.04; p<0.001) identifies patients with relapse/absence of remission after surgical treatment (sensitivity = 100%, specificity = 88.9%).

CONCLUSION

The TSH-PA in the structure of PAs is extremely rare, and as a result, most of them are misdiagnosed and detected already at the stage of macroadenoma. The most effective method of treatment is transnasal transsphenoidal adenomectomy. Somatostatin analogues can be used as second-line therapy if surgical treatment is ineffective. We have proposed a possible model for postoperative TSH levels (>0.391 mU/l) to predict recurrence of TSH-PA, which requires validation on an expanded number of cases.

Multilineage Pituitary Neuroendocrine Tumors (PitNETs) Expressing PIT1 and SF1

PitNETs are usually restricted in their cytodifferentiation to only one of 3 lineages dictated by expression of the pituitary transcription factors (TFs) PIT1, TPIT, or SF1. Tumors that show lineage infidelity and express multiple TFs are rare. We searched the pathology files of 4 institutions for PitNETs with coexpression of PIT1 and SF1. We identified 38 tumors in 21 women and 17 men, average age 53 (range 21-79) years. They represented 1.3 to 2.5% of PitNETs at each center. Acromegaly was the presentation in 26 patients; 2 had central hyperthyroidism associated with growth hormone (GH) excess and one had significantly elevated prolactin (PRL). The remainder had mass lesions with visual deficits, hypopituitarism, and/or headaches. Tumor size ranged from 0.9 to 5 cm; all 7 lesions smaller than 1 cm were associated with acromegaly. Larger lesions frequently invaded the cavernous sinuses. Four cases represented a second attempt at surgical resection. PIT1 was usually diffusely positive but 5 cases had variable (patchy or focal) staining. SF1 reactivity was variable in intensity but diffuse in all but 2 cases. GATA3 data, available in 14 cases, identified diffuse positivity in 5 and focal staining in 1. GH was expressed in all but 5 tumors, PRL and thyrotropin (TSH) were expressed in 14 and 13, respectively, follicle-stimulating hormone (FSH) in 11 of 18, and luteinizing hormone (LH) in 4 of 17. Keratin staining patterns were diffuse perinuclear/membranous in 27, variable perinuclear in 4, and negative in 3; scattered fibrous bodies were seen in 5 and diffuse fibrous bodies in 1. Ki67 labeling index ranged from < 1 to 7.9%. In 3 cases, these tumors represented one of multiple synchronous PitNETs; a separate corticotroph tumor was seen in 2 patients and one patient had 2 additional discrete lesions, a sparsely granulated lactotroph, and a pure gonadotroph tumor comprising a triple tumor. PitNETs expressing PIT1 and SF1 represent multilineage PitNETs. These rare tumors have variable clinical and morphological features, most often presenting as large tumors with GH excess and occasionally as one of multiple synchronous PitNETs of distinct lineages.

Clinical features and therapeutic outcomes of GH/TSH cosecreting pituitary adenomas: experience of a single pituitary center

Background

Growth hormone (GH)/thyroid stimulating hormone (TSH) cosecreting pituitary adenoma (PA) is an exceedingly rare kind of bihormonal pituitary neuroendocrine tumors (PitNETs). Its clinical characteristics have rarely been reported.

Objectives

This study aimed to summarize the clinical characteristics and experience of diagnosis and treatment among patients with mixed GH/TSH PAs from a single center.

Methods

We retrospectively reviewed GH/TSH cosecreting PAs from 2063 patients diagnosed with GH-secreting PAs admitted to Peking Union Medical College Hospital between January 1st, 2010, and August 30th, 2022, to investigate the clinical characteristics, hormone detection, imaging findings, treatment patterns and outcomes of follow-up. We further compared these mixed adenomas with age- and sex-matched cases of GH mono-secreting PAs (GHPAs). The data of the included subjects were collected using electronic records from the hospital's information system.

Results

Based on the inclusion and exclusion criteria, 21 GH/TSH cosecreting PAs were included. The average age of symptom onset was 41.6 ± 14.9 years old, and delayed diagnosis occurred in 57.1% (12/21) of patients. Thyrotoxicosis was the most common complaint (10/21, 47.6%). The median inhibition rates of GH and TSH in octreotide suppression tests were 79.1% [68.8%, 82.0%] and 94.7% [88.2%, 97.0%], respectively. All these mixed PAs were macroadenomas, and 23.8% (5/21) of them were giant adenomas. Comprehensive treatment strategies comprised of two or more therapy methods were applied in 66.7% (14/21) of patients. Complete remission of both GH and TSH was accomplished in one-third of cases. In the comparison with the matched GHPA subjects, the mixed GH/TSH group presented with a higher maximum diameter of the tumor (24.0 [15.0, 36.0] mm vs. 14.7 [10.8, 23.0] mm, P = 0.005), a greater incidence of cavernous sinus invasion (57.1% vs. 23.8%, P = 0.009) and a greater difficulty of long-term remission (28.6% vs. 71.4%, P <0.001). In addition, higher occurrence rates of arrhythmia (28.6% vs. 2.4%, P = 0.004), heart enlargement (33.3% vs. 4.8%, P = 0.005) and osteopenia/osteoporosis (33.3% vs. 2.4%, P = 0.001) were observed in the mixed PA group.

Conclusion

There are great challenges in the treatment and management of GH/TSH cosecreting PA. Early diagnosis, multidisciplinary therapy and careful follow-up are required to improve the prognosis of this bihormonal PA.

Single Cell Metabolic Landscape of Pituitary Neuroendocrine Tumor Subgroups and Lineages

Pituitary neuroendocrine tumors (PitNETs) are common intracranial tumors comprising numerous subtypes whose metabolic profiles have yet to be fully examined. The present in silico study analyzed single-cell expression profiles from 2311 PitNET cells from various lineages and subtypes to elucidate differences in metabolic activities. Gonadotroph tumors exhibited high activities with histidine metabolism, whose activity is low in lactotroph tumors. Somatotroph tumors enriched for sulfur and tyrosine metabolism, while lactotroph tumors were enriched metabolism of nitrogen, ascorbate, and aldarate. PIT-1 lineage tumors exhibited high sulfur and thiamine metabolism. These results set precedence for further translational studies for subgroup/lineage specific targeted therapies.

Thyrotropin-secreting tumor "TSH-PitNET": From diagnosis to treatment

Thyrotropic adenomas (TSH-PitNET) are the rarest pituitary tumours. Most TSH-PitNETs are secreting adenoma, with a biological picture of inappropriate TSH secretion (moderately elevated TSH, elevated FT3 and FT4). Patients present most often clinical hyperthyroidism, but with more moderate symptoms than in peripheral hyperthyroidism. Biological diagnosis is not always easy. The main differential diagnoses are interfering antibody assay interactions, dysalbuminemia and thyroid hormone resistance syndrome. Misdiagnosis is common. However, the diagnosis is easier when macroadenomas are involved (80% of cases), with symptoms of optic chiasm compression, headache and signs of hypopituitarism. Treatment is initially based on surgery. In case of failure, somatostatin analogues are very effective in controlling tumor volume and secretion, although there is a risk of thyroid insufficiency, which is usually transient.

Integrated proteogenomic characterization across major histological types of pituitary neuroendocrine tumors

Pituitary neuroendocrine tumor (PitNET) is one of the most common intracranial tumors. Due to its extensive tumor heterogeneity and the lack of high-quality tissues for biomarker discovery, the causative molecular mechanisms are far from being fully defined. Therefore, more studies are needed to improve the current clinicopathological classification system, and advanced treatment strategies such as targeted therapy and immunotherapy are yet to be explored. Here, we performed the largest integrative genomics, transcriptomics, proteomics, and phosphoproteomics analysis reported to date for a cohort of 200 PitNET patients. Genomics data indicate that GNAS copy number gain can serve as a reliable diagnostic marker for hyperproliferation of the PIT1 lineage. Proteomics-based classification of PitNETs identified 7 clusters, among which, tumors overexpressing epithelial-mesenchymal transition (EMT) markers clustered into a more invasive subgroup. Further analysis identified potential therapeutic targets, including CDK6, TWIST1, EGFR, and VEGFR2, for different clusters. Immune subtyping to explore the potential for application of immunotherapy in PitNET identified an association between alterations in the JAK1-STAT1-PDL1 axis and immune exhaustion, and between changes in the JAK3-STAT6-FOS/JUN axis and immune infiltration. These identified molecular markers and alternations in various clusters/subtypes were further confirmed in an independent cohort of 750 PitNET patients. This proteogenomic analysis across traditional histological boundaries improves our current understanding of PitNET pathophysiology and suggests novel therapeutic targets and strategies.

The Endoscopic Endonasal Transsphenoidal Approach for Thyrotropin-Secreting Pituitary Adenomas: Single-Center Experience and Clinical Outcomes of 49 Patients

OBJECTIVE

To analyze surgical outcomes and tumor characteristics of 49 patients with thyrotropin-secreting pituitary adenoma, a rare functional pituitary adenoma subtype with challenging surgery, who underwent endoscopic endonasal transsphenoidal surgery.

METHODS

In this single-center study, clinical, radiological, surgical, and endocrinological data of 49 patients diagnosed with thyrotropin-secreting pituitary adenoma were retrospectively reviewed.

RESULTS

Mean tumor size was 21.12 mm (6 microadenomas, 41 macroadenomas, 2 giant adenomas). Cavernous sinus invasion was present in 12 (24.48%) patients. Tumor consistency was firm in 23 (46.93%) patients. Plurihormonal secretion characteristics were present in 9 patients (5 growth hormone + thyrotropin and 4 growth hormone + prolactin + thyrotropin). Mean follow-up duration was 51.73 months. Of the cases with firm tumors, 14 patients had a history of antithyroid drug use; there was no statistically significant correlation between the antithyroid medication and the firmness of the tumor. Gross total resection was achieved in 32 (65.30%) cases, near-total resection was achieved in 14 (28.57%) cases, and subtotal resection was achieved in 3 (6.12%) cases. The analysis showed that the negative effect of >2 cm tumor size and cavernous sinus invasion on resection rate was statistically significant (P < 0.001). Although early remission was achieved in 33 (67.34%) patients, 44 (89.79%) patients were in euthyroid state at >3 months' follow-up. Complications were 4 new-onset pituitary deficiencies, 3 cases of permanent diabetes insipidus, 1 thyrotoxic crisis, and 1 cerebrospinal fluid leak.

CONCLUSIONS

Endoscopic endonasal transsphenoidal surgery is the first-line treatment in thyrotropin-secreting pituitary adenoma and should be performed in a tertiary center. Gross total resection is the goal, and early diagnosis is essential for surgical success.

A Retrospective Trail Investigating Temozolomide Neoadjuvant Chemotherapy Combined with Radiotherapy in Low-Grade Pituitary Tumors

Objective. To study and analyze the clinical application of temozolomide (TMZ) combined with radiotherapy in the treatment of low-grade pituitary tumors. Methods. A retrospective trail was conducted among 67 patients with low-grade pituitary tumors who were treated in our hospital from March 2018 to June 2020. According to different treatment methods, they were assigned into a combined group (37 cases, temozolomide capsules and radiotherapy) and a control group (30 cases, radiotherapy). The changes of serum prolactin (PRL), insulin-like growth factor-1 (IGF-1), GH levels, thyroid-stimulating hormone (TSH), serum free thyroxine (FT4), and adrenocorticotropic hormone (ACTH) were compared. Results. The chi-square test reports a significantly higher total effective rate in the combined group vs. control group (91.89% vs. 70.00%). Significant reductions in serum levels of PRL, IGF-1, and GH were observed in both groups after treatment, whereas the combined group treated with radiotherapy and TMZ resulted in significantly lower levels compared with the control group ( $p<0.05$ ). After treatment, TSH decreased, and FT4 and ACTH increased in both groups, and the treatment with radiotherapy and TMZ in the combined group led to a significantly greater amplitude of variation ( $p<0.05$ ). Conclusion. The combination of temozolomide and radiotherapy might be a promising technique for the treatment of pituitary tumors, thereby meriting promotion.

Overview of the 2022 WHO Classification of Pituitary Tumors

This review summarizes the changes in the 5th Edition of the WHO Classification of Endocrine and Neuroendocrine Tumors that relate to the pituitary gland. The new classification clearly distinguishes anterior lobe (adenohypophyseal) from posterior lobe (neurohypophyseal) and hypothalamic tumors. Other tumors arising in the sellar region are also discussed. Anterior lobe tumors include (i) well-differentiated adenohypophyseal tumors that are now classified as pituitary neuroendocrine tumors (PitNETs; formerly known as pituitary adenomas), (ii) pituitary blastoma, and (iii) the two types of craniopharyngioma. The new WHO classification provides detailed histological subtyping of a PitNET based on the tumor cell lineage, cell type, and related characteristics. The routine use of immunohistochemistry for pituitary transcription factors (PIT1, TPIT, SF1, GATA3, and ERα) is endorsed in this classification. The major PIT1, TPIT, and SF1 lineage-defined PitNET types and subtypes feature distinct morphologic, molecular, and clinical differences. The "null cell" tumor, which is a diagnosis of exclusion, is reserved for PitNETs with no evidence of adenohypophyseal lineage differentiation. Unlike the 2017 WHO classification, mammosomatotroph and acidophil stem cell tumors represent distinct PIT1-lineage PitNETs. The diagnostic category of PIT1-positive plurihormonal tumor that was introduced in the 2017 WHO classification is replaced by two clinicopathologically distinct PitNETs: the immature PIT1-lineage tumor (formerly known as silent subtype 3 tumor) and the mature plurihormonal PIT1-lineage tumor. Rare unusual plurihormonal tumors feature multi-lineage differentiation. The importance of recognizing multiple synchronous PitNETs is emphasized to avoid misclassification. The term "metastatic PitNET" is advocated to replace the previous terminology "pituitary carcinoma" in order to avoid confusion with neuroendocrine carcinoma (a poorly differentiated epithelial neuroendocrine neoplasm). Subtypes of PitNETs that are associated with a high risk of adverse biology are emphasized within their cell lineage and cell type as well as based on clinical variables. Posterior lobe tumors, the family of pituicyte tumors, include the traditional pituicytoma, the oncocytic form (spindle cell oncocytoma), the granular cell form (granular cell tumor), and the ependymal type (sellar ependymoma). Although these historical terms are entrenched in the literature, they are nonspecific and confusing, such that oncocytic pituicytoma, granular cell pituicytoma, and ependymal pituicytoma are now proposed as more accurate. Tumors with hypothalamic neuronal differentiation are classified as gangliocytomas or neurocytomas based on large and small cell size, respectively. This classification sets the standard for a high degree of sophistication to allow individualized patient management approaches.

A Preoperative MRI-Based Radiomics-Clinicopathological Classifier to Predict the Recurrence of Pituitary Macroadenoma Within 5 Years

Objective: To investigate the ability of a MRI-based radiomics-clinicopathological model to predict pituitary macroadenoma (PMA) recurrence within 5 years.

Materials and Methods: We recruited 74 recurrent and 94 non-recurrent subjects, following first surgery with 5-year follow-up data. Univariate and multivariate analyses were conducted to identify independent clinicopathological risk factors. Two independent and blinded neuroradiologists used 3D-Slicer software to manually delineate whole tumors using preoperative axial contrast-enhanced T1WI (CE-T1WI) images. 3D-Slicer was then used to extract radiomics features from segmented tumors. Dimensionality reduction was carried out by the least absolute shrinkage and selection operator (LASSO). Two multilayer perceptron (MLP) models were established, including independent clinicopathological risk factors (Model 1) and a combination of screened radiomics features and independent clinicopathological markers (Model 2). The predictive performance of these models was evaluated by receiver operator characteristic (ROC) curve analysis.

Results: In total, 1,130 features were identified, and 4 of these were selected by LASSO. In the test set, the area under the curve (AUC) of Model 2 was superior to Model 1 {0.783, [95% confidence interval (CI): 0.718—.860] vs. 0.739, (95% CI: 0.665–0.818)}. Model 2 also yielded the higher accuracy (0.808 vs. 0.692), sensitivity (0.826 vs. 0.652), and specificity (0.793 vs. 0.724) than Model 1.

Conclusions: The integrated classifier was superior to a clinical classifier and may facilitate the prediction of individualized prognosis and therapy.

Combination of transsphenoidal endoscopic surgery and presurgical somatostatin analogs in thyrotropin (TSH)-secreting pituitary adenomas: Treatment outcome and long-term remission at a single pituitary center

BACKGROUND

Thyrotropin (TSH)-secreting pituitary adenomas (TSHomas) account for an extremely rare group of pituitary adenomas. Few studies examined the sensitivity and efficacy of presurgical somatostatin analogs (SSAs) and described the long-term remission under such treatment modality. The aim of the present study was to assess the efficacy of presurgical SSA treatment and long-term remission after surgery.

METHODS

A retrospective cohort of 65 TSHoma patients who received endoscopic transsphenoidal pituitary surgery between 2011 and 2020 in a single pituitary center in China was established. Data were analyzed for sex differences and different types of SSA and ultimately to explore the hormonal cutoff for remission prediction.

RESULTS

TSHomas had a predominant female preference in this cohort (43 women vs. 22 men). Baseline FT3 was higher in men [7.543 ± 2.407 vs. 5.58 (4.99, 6.58), p = 0.019], which was consistent with its longer diagnosis time and larger tumor volume. The median medication time for hormonal control was 2. 5 days for short-acting SSA and 4. 0 weeks for long-term SSA. Patients with long-acting SSA had a shrinking maximum tumor diameter at a median of 1.0 (-1.6, 4.925) mm. Only 10 patients (15.38%) were not in complete remission among whom 8 patients were not en-bloc resected and 2 patients had tumor recurrence after 81.6 and 10. 7 months of complete removal. Postsurgical thyroid hormones (within 1 week) of TSH <0.094 μIU/ml were identified as the cutoff for remission using the ROC curve.

CONCLUSIONS

The combination of endoscopic transsphenoidal surgery and presurgical SSA TSHomas provided a higher long-term remission for TSHomas.

An Update on Pituitary Neuroendocrine Tumors Leading to Acromegaly and Gigantism

An excess of growth hormone (GH) results in accelerated growth and in childhood, the clinical manifestation is gigantism. When GH excess has its onset after epiphyseal fusion at puberty, the overgrowth of soft tissue and bone results in acromegaly. Persistent GH excess in gigantism also causes acromegalic features that become evident in the adult years. The causes of GH excess are primarily lesions in the pituitary, which is the main source of GH. In this review, we provide an update on the clinical, radiological and pathologic features of the various types of pituitary neuroendocrine tumors (PitNETs) that produce GH. These tumors are all derived from PIT1-lineage cells. Those composed of somatotrophs may be densely granulated, resembling normal somatotrophs, or sparsely granulated with unusual fibrous bodies. Those composed of mammosomatotrophs also produce prolactin; rare plurihormonal tumors composed of cells that resemble mammosomatotrophs also produce TSH. Some PitNETs are composed of immature PIT1-lineage cells that do not resemble differentiated somatotrophs, mammosomatotrophs, lactotroph or thyrotrophs; these tumors may cause GH excess. An unusual oncocytic PIT1-lineage tumor known as the acidophil stem cell tumor is predominantly a lactotroph tumor but may express GH. Immature PIT1-lineage cells that express variable amounts of hormones alone or in combination can sometimes cause GH excess. Unusual tumors that do not follow normal lineage differentiation may also secrete GH. Exceptional examples of acromegaly/gigantism are caused by sellar tumors composed of hypothalamic GHRH-producing neurons, alone or associated with a sparsely granulated somatotroph tumor. Each of these various tumors has distinct clinical, biochemical and radiological features. Data from careful studies based on morphologic subtyping indicate that morphologic classification has both prognostic and predictive value.

Clinical and Therapeutic Characteristics of Pituitary TSH-Secreting Adenoma in Adolescent-Onset Patients: Six Case Studies and Literature Review

BACKGROUND

Thyrotropin-secreting adenoma (TSH-oma) is a very rare kind of functional pituitary adenoma, especially that which occurs in adolescents. However, its potential clinical and therapeutic characteristics are still unknown.

OBJECTIVES

The study was aimed to summarize the clinical and therapeutic characteristics of patients with adolescent-onset TSH-oma.

METHODS

We retrospectively analyzed six (4.1%) adolescent-onset TSH-oma cases from 148 patients who were diagnosed with TSH-oma at our hospital between January 2012 and October 2020. A literature review was performed on the PubMed online database, and 14 adolescent-onset TSH-oma cases were retrieved. Then, the characteristics of clinical manifestations, treatment outcomes, and follow-ups were analyzed and compared to the adult TSH-oma patients.

RESULTS

Altogether, 20 adolescent-onset cases were included in this study having mean onset age of 13.4 ± 3.3 years. Males were found to be slightly predominant (M: F = 1.5:1) in our study. The median baseline levels of TSH, FT3, and FT4 in adolescent-onset cases were found to be 6.30 [interquartile range (IQR) 9.82] µIU/ml, 9.18 (IQR 11.61) pg/ml, and 3.22 (IQR 1.90) ng/dl, respectively, which were all significantly higher than the adult patients of our hospital. Also, the adolescent-onset cases showed more large tumor ratio (36.8% vs. 9.3%, p = 0.007) compared to the adult patients. Compared to the patients of all ages in the literature, the biochemical remission rate of SSAs (57.1%) and remission rate of TSS (38.9%) were found to be considerably lower in adolescent-onset patients, while the recurrence rate (44.4%) was found to be considerably higher.

CONCLUSIONS

Adolescent-onset TSH-oma patients showed higher TSH and thyroid hormone levels, more large tumors, and worse treatment outcomes than adult cases. Hence, early diagnosis, multidisciplinary therapy, and close follow-up should be highlighted to improve the prognosis.

A Preoperative MRI-Based Radiomics-Clinicopathological Classifier to Predict the Recurrence of Pituitary Macroadenoma Within 5 Years

Objective: To investigate the ability of a MRI-based radiomics-clinicopathological model to predict pituitary macroadenoma (PMA) recurrence within 5 years. Materials and Methods: We recruited 74 recurrent and 94 non-recurrent subjects, following first surgery with 5-year follow-up data. Univariate and multivariate analyses were conducted to identify independent clinicopathological risk factors. Two independent and blinded neuroradiologists used 3D-Slicer software to manually delineate whole tumors using preoperative axial contrast-enhanced T1WI (CE-T1WI) images. 3D-Slicer was then used to extract radiomics features from segmented tumors. Dimensionality reduction was carried out by the least absolute shrinkage and selection operator (LASSO). Two multilayer perceptron (MLP) models were established, including independent clinicopathological risk factors (Model 1) and a combination of screened radiomics features and independent clinicopathological markers (Model 2). The predictive performance of these models was evaluated by receiver operator characteristic (ROC) curve analysis. Results: In total, 1,130 features were identified, and 4 of these were selected by LASSO. In the test set, the area under the curve (AUC) of Model 2 was superior to Model 1 {0.783, [95% confidence interval (CI): 0.718-.860] vs. 0.739, (95% CI: 0.665-0.818)}. Model 2 also yielded the higher accuracy (0.808 vs. 0.692), sensitivity (0.826 vs. 0.652), and specificity (0.793 vs. 0.724) than Model 1. Conclusions: The integrated classifier was superior to a clinical classifier and may facilitate the prediction of individualized prognosis and therapy.