Cerebrospinal Fluid Metabolomic Pattern of Different Pituitary Stalk Lesions

OBJECTIVE

To describe the cerebrospinal fluid (CSF) metabolomic pattern of pituitary stalk lesions.

METHODS

CSF was collected from patients with different pituitary stalk lesions treated at Peking Union Medical College Hospital: germ cell tumor (GCT, n = 27); hypophysitis (n = 10); and Langerhans cell histiocytosis (LCH) or Erdheim-Chester disease (ECD) (LCH + ECD, n = 10). The CSF metabolome profiles were characterized by liquid chromatography-mass spectrometry (LC-MS).

RESULTS

There were 44 metabolites that significantly differed between patients with GCT and those with hypophysitis (P < .05). Between patients with GCT with CSF level of beta subunit of human chorionic gonadotrophin (β-hCG) < 5 mIU/mL and those with hypophysitis, there were 15 differential metabolites (P < .05, fold change > 1.5 or < 1/1.5). All of the metabolites had an area under the curve (AUC) above 0.7. There were 9 metabolites that significantly differed between patients with GCT and those with LCH + ECD (P < .05) and 7 metabolites had significant differences between GCT (CSF β-hCG < 5 mIU/mL) and LCH + ECD (P < .05, fold change > 1.5 or < 1/1.5). We found 6 metabolites that were significantly different between patients with hypophysitis and those with LCH + ECD (P < .05) and 5 of these had fold change more than 1.5 or less than 1/1.5. Three metabolites, 5-deoxydiplosporin, cloversaponin I, and phytosphingosine, showed excellent capabilities to differentiate the 3 disease categories. Furthermore, we identified 67 metabolites associated with clinical test results (ρ > 0.2, P < .05) and 29 metabolites showed strong correlation (ρ > 0.4, P < .05).

CONCLUSION

Our study is the first to systematically investigate the metabolomics of CSF in different pituitary stalk lesions. CSF metabolomics is a useful strategy for biomarker discovery.

Clinical features of anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis: a new aspect of paraneoplastic autoimmune condition

The pathogenesis of anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis was gradually revealed as cases emerged. Our comprehensive analysis, including all reported cases, identified a new instance of anti-PIT-1 hypophysitis postimmune checkpoint inhibitor therapy. All 9 patients exhibited extremely low growth hormone (GH), prolactin (PRL), and thyroid-stimulating hormone (TSH) levels; 2 had a slightly atrophic pituitary gland; 4 had thymoma, and 5 had malignant neoplasms of diffuse large B-cell lymphoma (DLBCL) and other origins. Patients with thymoma showed multiple autoimmune diseases. HLA-A*24:02 and/or A*02:06 were present in six and DR53 in 5 cases analyzed. High anti-PIT-1 antibody titers and ectopic PIT-1 expression in the cytosol and nucleus of the tumor tissues were observed in patients with thymoma or DLBCL, whereas it was exclusively observed in the nuclei of a bladder cancer patient. These findings provide new insights into the pathophysiology of paraneoplastic autoimmune hypophysitis.

Preferential B cell differentiation by combined immune checkpoint blockade for renal cell carcinoma is associated with clinical response and autoimmune reactions

Combined immune checkpoint blockade (ICB) is effective therapy for renal cell carcinoma (RCC). However, the dynamic changes in circulating B cells induced by combined ICB have not been clarified. The present study prospectively examined 22 patients scheduled to receive ICB for unresectable or metastatic RCC between March 2018 and August 2021. Eleven patients received combined therapy with anti-PD-1 (nivolumab) and anti-CTLA-4 (ipilimumab), and the other 11 patients received nivolumab monotherapy. Comprehensive phenotypes of circulating immune cells obtained prior to and after ICB therapy were analyzed by flow cytometry. Although the proportion of naïve B cells among total B cells was significantly decreased, that of switched memory B cells was significantly increased after combined therapy. In responders, the proportion of B cells among peripheral blood mononuclear cells was significantly higher prior to ICB therapy, and the proportion of switched memory B cells among total B cells tended to increase after ICB therapy. Of note, the proportion of plasmablasts among total B cells was significantly increased after ICB therapy in patients who developed severe immune-related adverse events (irAEs), and the proportion of B cells among peripheral blood decreased significantly. Furthermore, in four of five patients who developed immune-related hypophysitis following combined therapy, anti-pituitary antibody was detected in the serum. These results suggested that immune-related hypophysitis was closely related to the increase in circulating plasmablasts. Collectively, this study suggests that combined ICB promotes the differentiation of B cell populations, which is associated with efficient tumor suppression and development of irAEs.

Central diabetes insipidus: a late sequela of BNT162b2 SARS-CoV-2 mRNA vaccine?

BACKGROUND

The development of an effective vaccine is a powerful tool to contain the global spread of coronavirus disease 2019 (COVID-19). Still, it raises potential safety concerns about the subsequent enhancement of associated immunopathology. Increasing evidence shows that the endocrine system, including the hypophysis, may be involved in COVID-19. Moreover, occasional but increasing reports of endocrine disorders involving the thyroid have been reported after the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine. Among them, a few cases encompass the pituitary. Here we report a rare case of central diabetes insipidus following SARS-CoV-2 vaccination.

CASE PRESENTATION

We report a 59-year-old female patient with a 25-year history of Crohn's disease in long-term remission, who presented with sudden onset of polyuria eight weeks after administration of an mRNA SARS-CoV-2 vaccination. Laboratory evaluation was consistent with isolated central diabetes insipidus. Magnetic resonance imaging displayed involvement of the infundibulum and the posterior hypophysis. Eighteen months after the vaccination, she is still under desmopressin treatment and had stable pituitary stalk thickening on magnetic resonance imaging. Although Crohn's disease-associated hypophysitis has been reported, it is scarce. In the absence of other recognizable causes of hypophysitis, we believe the involvement of the hypophysis in our patient may have been triggered by the SARS-CoV-2 vaccine.

CONCLUSIONS

We report a rare case of central diabetes insipidus potentially associated with SARS-CoV-2 mRNA vaccination. Further studies are needed to understand better the mechanisms underlying autoimmune endocrinopathies development in the context of COVID-19 infection and SARS-CoV-2 vaccination.

Frequency and clinical characteristics of hypophysitis and hypopituitarism in patients undergoing immunotherapy - A systematic review

OBJECTIVE

To describe the frequency of hypophysitis and hypopituitarism in cancer patients who are undergoing antineoplastic treatment with immunotherapy, as well as to describe the clinical, epidemiological, and demographic characteristics of these patients.

METHODS

A systematic search of the literature in PubMed, Embase, Web of Science, ClinicalTrials.gov and Cochrane Controlled Register of Trials took place on May 8 and 9, 2020. Randomized and nonrandomized clinical trials, cohort studies, case-control studies, case series and case reports were included.

RESULTS

A total of 239 articles were obtained, in which 963 cases of hypophysitis and 128 cases of hypopituitarism were found in a treated population of 30,014 individuals (3.20% and 0.42% of the evaluated population, respectively). In the cohort studies, the incidence of hypophysitis and hypopituitarism ranged from 0% to 27.59% and from 0% to 17.86%, respectively. In the non-randomized clinical trials, the incidence of hypophysitis and hypopituitarism ranged from 0% to 25% and from 0% to 14.67%, and in randomized clinical trials from 0% to 16.2% and from 0% to 33.33%. The most common hormonal changes were in the corticotrophic, thyrotrophic and gonadotrophic axes. The main magnetic resonance imaging (MRI) findings were enlargement of the pituitary gland and enhanced contrast uptake. The main symptoms presented by patients with hypophysitis were fatigue and headache.

CONCLUSION

The present review reported a frequency of hypophysitis and hypopituitarism of 3.20% and 0.42%, respectively, in the evaluated population. The clinical-epidemiological characteristics of patients affected by hypophysitis were also described.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier CRD42020175864.

Generating novel pituitary datasets from open-source imaging data and deep volumetric segmentation

PURPOSE

The estimated incidence of pituitary adenomas in the general population is 10-30%, yet radiographic diagnosis remains a challenge. Diagnosis is complicated by the heterogeneity of radiographic features in both normal (e.g. complex anatomy, pregnancy) and pathologic states (e.g. primary endocrinopathy, hypophysitis). Clinical symptoms and laboratory testing are often equivocal, which can result in misdiagnosis or unnecessary specialist referrals. Computer vision models can aid in pituitary adenoma diagnosis; however, a major challenge to model development is the lack of dedicated pituitary imaging datasets. We hypothesized that deep volumetric segmentation models trained to extract the sellar and parasellar region from existing whole-brain MRI scans could be used to generate a novel dataset of pituitary imaging.

METHODS

Six open-source whole-brain MRI datasets, created for research purposes, were included for model development. Deep learning-based volumetric segmentation models were trained using 318 manually annotated MRI scans from a single open-source MRI dataset. Out-of-distribution volumetric segmentation performance was then tested on 418 MRIs from five held-out research datasets.

RESULTS

On our annotated images, agreement between manual and model volumetric segmentations was high. Dice scores (a measure of overlap) ranged 0.76-0.82 for both in-distribution and out-of-distribution model testing. In total, 6,755 MRIs from six data sources were included in the final generated pituitary dataset.

CONCLUSIONS

We present the first and largest dataset of pituitary imaging constructed using existing MRI data and deep volumetric segmentation models trained to identify sellar and parasellar anatomy. The model generalizes well across patient populations and MRI scanner types. We hope our pituitary dataset will be an integral part of future machine learning research on pituitary pathologies.

Idiopathic granulomatous hypophysitis mimicking adenoma

Hypophysitis is a rare disease of pituitary gland, which, although it is usually a primary lesion, can also occur secondary to systemic conditions. Granulomatous hypophysitis is an inflammatory disease condition which accounts for less than 1% of all cellular lesions and can mimic adenoma. A 32-year-old woman presented with weight gain, galactorrhea and blurred vision. The MRI showed a cystic, nodular lesion in the intermediate lobe of the pituitary gland and the initial diagnosis was adenoma. She underwent surgery and the histopathology revealed granulomas composed of epithelioid histiocytes, multinuclear giant cells and mononuclear inflammatory cells. Inflammatory diseases of the pituitary gland are much less frequent than pituitary adenomas and idiopathic granulomatous hypophysitis is extremely rare. Histopathology and the ruling out of a systemic cause are the gold standards for its diagnosis.

Discrimination between non-functioning pituitary adenomas and hypophysitis using machine learning methods based on magnetic resonance imaging‑derived texture features

PURPOSE

Hypophysitis is a heterogeneous condition that includes inflammation of the pituitary gland and infundibulum, and it can cause symptoms related to mass effects and hormonal deficiencies. We aimed to evaluate the potential role of machine learning methods in differentiating hypophysitis from non-functioning pituitary adenomas.

METHODS

The radiomic parameters obtained from T1A-C images were used. Among the radiomic parameters, parameters capable of distinguishing between hypophysitis and non-functioning pituitary adenomas were selected. In order to avoid the effects of confounding factors and to improve the performance of the classifiers, parameters with high correlation with each other were eliminated. Machine learning algorithms were performed with the combination of gray-level run-length matrix-low gray level run emphasis, gray-level co-occurrence matrix-correlation, and gray-level co-occurrence entropy.

RESULTS

A total of 34 patients were included, 17 of whom had hypophysitis and 17 had non-functioning pituitary adenomas. Among the 38 radiomics parameters obtained from post-contrast T1-weighted images, 10 tissue features that could differentiate the lesions were selected. Machine learning algorithms were performed using three selected parameters; gray level run length matrix-low gray level run emphasis, gray-level co-occurrence matrix-correlation, and gray level co-occurrence entropy. Error matrices were calculated by using the machine learning algorithm and it was seen that support vector machines showed the best performance in distinguishing the two lesion types.

CONCLUSIONS

Our analysis reported that support vector machines showed the best performance in distinguishing hypophysitis from non-functioning pituitary adenomas, emphasizing the importance of machine learning in differentiating the two lesions.

Differential diagnosis of pituitary enlargement

Enlargement of the pituitary gland is heterogenous in the etiology. Common causes of pituitary enlargement are physiological hypertrophy during pregnancy, primary and secondary tumors, autoimmune hypophysitis including side effects of anticancer therapy with check-point inhibitors. Terms like hypertrophy, hyperplasia, sellar expansion and hypophysitis are commonly used to describe enlargement of the pituitary gland on MR scan regardless its etiology. The most common pathology causing pituitary gland enlargement is pituitary adenoma. Magnetic resonance imaging can differentiate pituitary tumors from diffuse enlargement due to hypophysitis in most but not all cases. Changes on imaging during time or response to pharmacotherapy might help determine the final diagnosis in uncertain cases. We present a case report of a young woman with sellar expansion due to prolonged untreated peripheral hypothyroidism mimicking pituitary adenoma. Interdisciplinary cooperation of endocrinologist, radiologist and neurosurgeon is crucial in determining the diagnosis.

Survival benefit of endocrine dysfunction following immune checkpoint inhibitors for nonthyroidal cancers

PURPOSE OF REVIEW

Our goal is to review pertinent data evaluating the association between immune checkpoint inhibitor (ICI)-induced endocrine dysfunction and survival in cancer patients as well as to understand the potential molecular links between these.

RECENT FINDINGS

ICIs have revolutionized cancer therapy but have also led to multiple immune-related adverse events (irAEs). Studies have demonstrated a link between the development of irAEs and improved survival, suggesting that ICI-induced antitumor immunity and autoimmunity are coupled. Thyroid irAEs are most frequently and strongly associated with improved survival, particularly in the context of overt thyroid dysfunction. Other endocrine irAEs, such as hypophysitis and diabetes are quite rare wherein the treatment approach or the disease process itself may mitigate improvement in survival. Preclinical and translational data indicate a role for CD4+ T cells, regulatory T cells and/or cytokines mediating irAEs, including thyroiditis.

SUMMARY

The development of irAEs is associated with improved tumor responses and survival in cancer patients. Thyroid irAEs, alone or in combination with other irAEs, are most strongly associated with improved outcomes. Biomarkers of response to ICIs are lacking, despite well-characterized pathologic and genomic susceptibilities predicting ICI efficacy. Early detection of thyroid irAEs may identify patients most likely to have durable antitumor response to ICIs. Although irAEs and antitumor immunity appear 'coupled', translational studies indicate the potential for their 'uncoupling', which could enable antitumor efficacy with greater safety margins.

[A Case of Hypophysitis Due to Immune Check Point Inhibitor Treatment]

The patient was a man in his 70s with bone metastasis from renal cell carcinoma who had received immune checkpoint inhibitors(ICI)therapy. After 2 courses of chemotherapy, he was admitted to our hospital with diverticulitis. His diverticulitis could be treated with antibiotics, but he presented with severe hyponatremia and consciousness disorder during hospitalization. Brain MRI showed pituitary swelling, and his serum TSH, ACTH, cortisol levels decreased. We therefore diagnosed him with hypopituitarism due to ICIs. Hydrocortisone improved his hyponatremia and consciousness disorder. Endocrine stimulation tests revealed no reaction of ACTH, and low-level reactions of TSH, LH and FSH, ICIs cause many types of immune- related adverse events(irAEs). The indications for ICI therapy are expanding; thus, we can expect to experience more cases of serious irAEs in association with ICI treatment. Further studies should be performed to improve our understanding of irAEs.