The early-stage clinical course of anti-pituitary-specific transcription factor-1 hypophysitis diagnosed post-immune checkpoint inhibitor treatment: A case with review of literature.

Anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis, a paraneoplastic syndrome resulting from an autoimmune response against PIT-1, typically manifests with undetectable levels of growth hormone (GH) and prolactin (PRL), and significantly low levels of serum thyroid-stimulating hormone (TSH) at diagnosis. These hormonal levels are highly specific to this disease and serve as key diagnostic indicators. Herein, we present a detailed clinical course of a 69-year-old male with a history of gastric cancer and lymph node metastases who developed anti-PIT-1 hypophysitis after the initiation of immune checkpoint inhibitor (ICI) therapy, specifically nivolumab, oxaliplatin, and capecitabine. The patient was referred to our department owing to decreased TSH, free triiodothyronine (T3), and free thyroxine (T4) levels after two doses of nivolumab. Initially suspected as central hypothyroidism due to ICI-related hypophysitis, further assessment confirmed the diagnosis of anti-PIT-1 hypophysitis. Notably, GH, PRL, and TSH levels markedly declined, leading to complete deficiencies 2 months after the first nivolumab dose-a pattern consistent with that of previous cases of anti-PIT-1 hypophysitis. Therefore, this report not only presents an atypical subset of ICI-related hypophysitis but also delineates the process of hormone impairment leading to complete deficiencies in anti-PIT-1 hypophysitis. This case highlights the importance of vigilant monitoring for endocrine issues in patients undergoing ICI therapy, given the escalating incidence of immune-related adverse events associated with the extensive use of ICI therapy for various cancers.

Early Serum Markers for Immune Checkpoint Inhibitor Induced Hypophysitis in Melanoma Patients.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have shown promising anti-tumor activities and are widely used for the treatment of advanced cancers. However, they may lead to immune-related adverse events (irAEs) and some of them, such as hypophysitis, can be life-threatening. Here, early diagnosis is critical. METHODS: We retrospectively analyzed 40 melanoma patients who developed hypophysitis during ICI treatment with either ipilimumab and/or anti-PD1 therapy and compared them to 40 control patients who did not develop hypophysitis during the ICI treatment, matched for age, gender, type of immunotherapy, and stage. Clinical data and blood values such as LDH, CRP, TSH, T3, T4, and absolute immune cell counts were retrieved from the medical records. Patient characteristics, laboratory values, progression-free survival, and overall survival were compared between the two groups. RESULTS: Patients with ir-hypophysitis had a median age of 59 years, and most of them were male. Clinically, frequent symptoms were fatigue, headache, dizziness, and gastrointestinal symptoms such as nausea or abdominal pain. The onset of ir-hypophysitis differed much between ipilimumab- (median 8 weeks) and anti-PD1 (median 40 weeks)-induced hypophysitis (p < 0.001). At baseline, besides a slightly increased CRP level (p = 0.06), no differences were observed in patients who later developed hypophysitis compared to the control. After treatment started, hypophysitis patients showed a constant and significant decline in T4 levels from the start of therapy until diagnosis (p < 0.05), independent of the ICI treatment regime. However, a decline in T3 and TSH was only noted in patients with ipilimumab-induced ir-hypophysitis. Furthermore, serum sodium levels declined rapidly at the diagnosis of hypophysitis (p < 0.001). In addition, there was a constant increase in the absolute counts of eosinophils and lymphocytes from baseline in hypophysitis patients (p < 0.05). CONCLUSION: Ir-hypophysitis reveals different clinical pictures and onset times depending on the ICI regime used. Whereas a drop in T4 levels was indicative of developing hypophysitis independent of the ICI regime, TSH levels only declined in patients under ipilimumab-based ICI regimes. To best monitor our patients, it is important to recognize these differences.

Secondary hypophysitis associated with Rathke's cleft cyst resembling a pituitary abscess.

Background: Although rare, cases of hypophysitis resembling a pituitary abscess (PA) have been reported. Differential diagnosis between hypophysitis and PA is crucial as the two diseases require different treatments. Case Description: A 38-year-old woman with headaches underwent head magnetic resonance imaging (MRI), which revealed an 11-mm mass lesion in the sella turcica. Due to breastfeeding, contrast-enhanced MRI was avoided. Pituitary adenomas and Rathke's cleft cyst (RCC) were suspected, and she was initially treated conservatively. Five months later, she acquired syndrome coronavirus two infections, and while the fever subsided with acetaminophen, the headache persisted. One month later, the headache worsened, followed by fever and diabetes insipidus. MRI revealed a pituitary cystic mass with ring-shaped contrast enhancement on T1-weighted MRI and increased signal intensity on diffusion-weighted imaging (DWI). PA was suspected, and emergency endoscopic transsphenoidal surgery was performed. The microbiological examination of the yellowish-brown content drained from the cystic mass was negative. Microscopically, the cystic lesion was covered with ciliated columnar epithelium and stratified squamous epithelium, with a dense inflammatory cell infiltrate consisting mainly of lymphocytes and plasma cells observed around the cyst. This supported the diagnosis of secondary hypophysitis associated with RCC without PA. Conclusion: We report a case of hypophysitis secondary to RCC resembling PA with ring-shaped contrast enhancement on MRI and increased signal intensity on DWI. This case emphasizes the need for cautious diagnosis of secondary hypophysitis due to RCC in individuals with MRIs and clinical manifestations resembling an abscess.

Effect of steroid therapy in a 16-year-old girl observed for lymphocytic hypophysitis.

Not required for Clinical Vignette.

Hypophysitis Secondary to Small Vessel ANCA Vasculitis Treated With Rituximab.

Background/Objective: Antineutrophil cytoplasmic antibody (ANCA) associated vasculitis is a rare small vessel vasculitis that can cause pituitary hypophysitis. Hypophysitis is difficult to treat, often requiring high doses of glucocorticoids with frequent flaring as glucocorticoids are tapered. We present a case of ANCA vasculitis involving the pituitary gland successfully treated with rituximab. Case Report: Fifty-one-year-old woman developed progressive frontal headaches, congestion, and epistaxis. Sinus computed tomography scan showed pituitary enlargement and chronic mucosal disease. Pituitary magnetic resonance imaging (MRI) confirmed a diffusely enlarged pituitary with a thickened pituitary stalk. Serologic evaluation revealed elevated inflammatory markers, positive perinuclear ANCA (p-ANCA), and an elevated serum anti-proteinase 3 (anti-PR3) antibody. The patient underwent pituitary biopsy, which showed adenohypophysitis with dense lymphoplasmacytic infiltration, some arranged perivascularly, compatible with involvement of the pituitary gland by ANCA vasculitis. The patient began rituximab and reported resolution of daily headaches, congestion, and epistaxis. Pituitary MRI scan 6 months after rituximab showed reduction in pituitary gland size and stalk thickening. Discussion: ANCA vasculitis is a rare etiology of pituitary hypophysitis, which can present a diagnostic and therapeutic challenge. Pituitary involvement of ANCA vasculitis can be identified through p-ANCA or cytoplasmic ANCA (c-ANCA) and biopsy of the involved tissue. Rituximab, a monoclonal antibody against CD20, has been successfully used to treat ANCA vasculitis and in this case, led to clinical improvements and reduction in the size of the pituitary gland. Conclusion: Pituitary biopsy enabled confirmation of ANCA hypophysitis and facilitated treatment with a steroid-sparing agent.

Endocrinopathies Associated With Immune Checkpoint Inhibitor Use.

OBJECTIVE: To provide a clinical approach towards immune checkpoint inhibitor (ICI)-associated endocrinopathies, their link with cancer outcomes, factors which differentiate them from other immune related adverse events, and health systems innovation to improve care for these patients. METHODS: A literature search for articles pertaining to ICIs and endocrinopathies was performed and supplemented by expert opinions of the authors. RESULTS: While immune related adverse events can affect almost any organ, they frequently target the endocrine glands, most commonly thyroid. Different classes of ICIs have varying frequencies of endocrinopathies related to hypophysitis, thyroiditis, diabetes mellitus, and rarely hypoadrenalism and hypoparathyroidism. ICI-associated endocrinopathies share some features with classic endocrine autoimmunity but appear to be a distinct entity. They can be challenging to diagnose and manage due to nonspecific clinical features, use of exogenous glucocorticoids, and at times rapid and severe hormone deficiency. The role of anti-inflammatory high-dose glucocorticoids is minimal, and the ICI does not usually require permanent discontinuation. ICI-associated endocrinopathies usually cause permanent hormone deficiency necessitating long-term management and patient engagement. ICI-thyroiditis has been associated with improved survival, while other endocrinopathies have not shown a significant association with outcomes in cancer patients receiving ICIs. Oncoendocrinology teams can improve the care of patients with ICI-associated endocrinopathies. CONCLUSION: This narrative review provides guidance to clinicians prescribing ICIs and those managing ICI-associated endocrinopathies, and complements the frameworks provided by major scientific societies in this field.

Endoscopic endonasal transsphenoidal surgery for unusual sellar lesions: eight cases and review of the literature.

Background: Preoperative imaging for some unusual lesions in the sellar region can pose challenges in establishing a definitive diagnosis, impacting treatment strategies. Methods: This study is a retrospective analysis of eight cases involving unusual sellar region lesions, all treated with endoscopic endonasal transsphenoidal surgery (EETS). We present the clinical, endocrine, and radiological characteristics, along with the outcomes of these cases. Results: Among the eight cases, the lesions were identified as follows: Solitary fibrous tumor (SFT) in one case, Lymphocytic hypophysitis (LYH) in one case, Cavernous sinus hemangiomas (CSH) in one case, Ossifying fibroma (OF) in two cases; Sphenoid sinus mucocele (SSM) in one case, Pituitary abscess (PA) in two cases. All patients underwent successful EETS, and their diagnoses were confirmed through pathological examination. Postoperatively, all patients had uneventful recoveries without occurrences of diabetes insipidus or visual impairment. Conclusion: Our study retrospectively analyzed eight unusual lesions of the sellar region. Some lesions exhibit specific imaging characteristics and clinical details that can aid in preoperative diagnosis and inform treatment strategies for these unusual sellar diseases.

Fluctuations in plasma adrenocorticotropic hormone concentration may predict the onset of immune checkpoint inhibitor-related hypophysitis.

Immune checkpoint inhibitor (ICI)-related hypophysitis (RH) is a common immune-related adverse event. The early detection of ICI-RH prevents life-threatening adrenal insufficiency. However, good predictors of secondary adrenal insufficiency in ICI-RH have not yet been reported. We hypothesized that fluctuations in serum adrenocorticotropic hormone (ACTH) and cortisol levels occur similarly to those in thyroid-stimulating hormone and thyroid hormone (thyroxine and triiodothyronine) levels in ICI-related thyroiditis. Here, we sought to test this hypothesis. Patients who used ICI and had a history of measurement of serum ACTH and cortisol concentrations were retrieved from electronic medical records, and those with a history of glucocorticoid use were excluded from the analysis. We evaluated fluctuations in serum ACTH and cortisol concentrations and the development of ICI-RH. For patients with ICI-RH, data at three points (before ICI administration (pre), maximum ACTH concentration (peak), and onset of ICI-RH) were analyzed to evaluate hormone fluctuations. A total of 202 patients were retrieved from the medical record. Forty-three patients were diagnosed with ICI-RH. Twenty-six out of 43 patients had sufficient data to evaluate fluctuations in serum ACTH and cortisol concentrations and no history of glucocorticoid use. ACTH concentrations changed from 37.4 (29.9-48.3) (pre) to 64.4 (46.5-106.2) (peak) pg/mL (1.72-fold increase, p=0.0026) in the patients with ICI-RH before the onset. There were no differences in cortisol concentrations between the pre and peak values in patients with ICI-RH. We also evaluated the fluctuations in serum ACTH and cortisol levels in patients who did not receive ICI-RH (62 cases). However, elevation of serum ACTH levels was not observed in patients without ICI-RH, suggesting that transient elevation of serum ACTH levels is a unique phenomenon in patients with ICI-RH. In conclusion, serum ACTH levels were transiently elevated in some patients with ICI-RH before the onset of secondary adrenal insufficiency. Monitoring the ACTH levels and their fluctuations may help predict the onset of ICI-RH.

PD-1/PD-L1 inhibitors associated hypophysitis: An analysis from the FAERS database and case reports.

To get a thorough understanding of PD-1/L1 inhibitor-related hypophysitis (PD-1/L1-irH), we utilized a combination of disproportionality analysis and case analysis to comprehensively characterize the clinical features of PD-1/L1-irH. Significant signals of hypophysitis were detected for all PD-1/PD-L1 inhibitors in the FAERS (FDA Adverse Event Reporting System). As revealed by both FAERS and the case analysis, PD-1/L1-irH occurred more commonly in males, PD-1 inhibitors users and patients older than 65 years. The median onset time was 101 days in FAERS and 8 cycles in the case analysis. In the case analysis, eight late-onset PD-1/L1-irHs occurred even after a discontinuation of several months (4-15 months). As revealed in FAERS, the outcome of PD-1/L1-irH tended to be poor, generally resulting in 64.66% hospitalization and 12.59% death. Fatigue was the most prominent symptom of PD-1/L1-irH, followed by anorexia, hyponatremia, and hypotension, as revealed by the analysis of 84 cases. Meanwhile isolated adrenocorticotropic (ACTH) deficiency was particularly prevalent for PD-1/L1-irH (85.71%), while gonadal hormones or posterior pituitary hormones deficiencies were rare. Glucocorticoids were administered to almost all cases (81/84), with a physiologic or stress dosage in 61.9% of cases, and a high-dose in 26.2% of cases. Most cases (58.3%) showed a favorable tumor response before diagnosis of PD-1/L1-irH. PD-1/L1-irH may occur throughout the whole therapy period even after discontinuation. Clinicians should pay more attention to PD-1 inhibitor users, males and older patients. Early diagnosis and prompt managements are crucial for PD-1/L1-irH as its potentially life-threatening nature.

Unique case of lymphocytic hypophysitis with normal pituitary hormone serology mimicking a non-functioning pituitary adenoma.

BACKGROUND: Lymphocytic hypophysitis is a rare autoimmune condition that usually presents during pregnancy and causes inflammation of the pituitary gland. Although the pathophysiology is not well understood, it often presents with headaches, visual disturbances, and symptoms of hypopituitarism. However, not all cases may present with hypopituitarism which can make this rare disease with an incidence of ~ 1 in 9 million much more difficult to diagnose. CASE PRESENTATION: We present a 35-year-old G4P4 woman with progressive vision loss and intermittent frontal headaches during her first trimester through 2 months postpartum. She presented with no symptoms of hypopituitarism and her hormone panel only showed elevated prolactin, possibly due to her breastfeeding. She was treated with a right pterional craniotomy with decompression of both optic nerves, partial resection of the suprasellar mass, and glucocorticoid therapy for headaches and visual disturbances. CONCLUSION: This case is notable for a presentation of lymphocytic hypophysitis without symptoms of hypopituitarism. This is important for outpatient providers to be aware of, especially those that care for pregnant patients so that unfavorable outcomes can be avoided.

Pituitary hypophysitis in granulomatosis with polyangiitis (GPA): a case series.

Granulomatosis with polyangiitis (GPA) rarely involves the pituitary gland. Pituitary involvement has been reported in ~ 1% of all cases of GPA. Most commonly, pituitary swelling and inflammation results in symptoms due to pituitary mass effect and arginine vasopressin deficiency. To date, there are no pituitary-specific treatment guidelines for this rare condition. We present three patients with GPA-related hypophysitis highlighting the spectrum of pituitary involvement. All three patients were successfully treated with immunosuppressive regimens that included rituximab (RTX). Following remission induction with high-dose glucocorticoids, patients received 6 monthly RTX for remission maintenance. RTX was well tolerated without significant side effects.

Hypophysitis after COVID-19 vaccination in a patient with Rathke's cleft cyst: A case report.

With the widespread vaccination of COVID-19 vaccine, a few cases have been reported that COVID-19 vaccine may cause endocrine disorders. A 59-y-old man presented with a loss of appetite after the first COVID-19 vaccination, which resolved spontaneously after 3 d. After the second COVID-19 vaccination, the symptoms including the loss of appetite, nausea, and vomiting reappeared and worsened along with loss of vision. He was found to have severe hyponatremia, and further investigations revealed secondary adrenal insufficiency, secondary hypothyroidism and Rathke's cleft cyst. The patient responded well to glucocorticoid and levothyroxine supplementation, and at 1-y follow-up the patient developed hypogonadism. We hypothesize that hypophysitis is probably induced by COVID-19 vaccine and report the rare but serious adverse reactions for early recognition and intervention.

Iatrogenic Pituitary Shutdown: A Rare Adverse Event of Programmed Cell Death-Ligand 1 Inhibitor.

Immune checkpoint inhibitors (ICIs) are one of the novel treatment strategies for malignancies, and their wide use has led to the emergence of immune-related adverse events (irAEs). Most of them have been reported in patients taking cytotoxic T lymphocyte-associated protein 4 inhibitors and are rarely reported among those taking programmed cell death-ligand protein 1 inhibitors. Here is a 74-year-old man who underwent treatment with atezolizumab for 33 weeks for hepatocellular carcinoma before presenting with chronic symptoms and laboratory results consistent with central adrenal insufficiency. Brain imaging did not show a possible culprit. He was incidentally found to have low thyrotropin (TSH) and low thyroxine prior to his presentation and began replacement with no further workup prior. We advocate keeping a low threshold for the diagnosis of adrenal insufficiency among patients taking ICIs and monitoring their pituitary hormones on a regular basis. Also, it is crucial to rule out pituitary hormonal deficiency among patients with central hypothyroidism prior to initiating replacement.

Coronavirus as a trigger of lymphocytic hypophysitis in an adolescent girl: An exceptional case report.

INTRODUCTION AND IMPORTANCE: Lymphocytic hypophysitis is an underestimated disease and the pathogenesis is still poorly elucidated. Post-coronavirus lymphocytic hypophysitis is a new emerging entity. CASE PRESENTATION: A 16-year-old previously healthy girl presented with pituitary tumor syndrome. She suffered from frontal headaches, polyuria-polydipsic syndrome, and impaired visual acuity. She was diagnosed with COVID-19 infection three weeks before. Contrast-enhanced magnetic resonance imaging (MRI) revealed pituitary enlargement with intense homogenous enhancement postgadolinium on T1 weighted images. The diagnosis of lymphocytic hypophysitis was made after ruling out other differential diagnosis. She was started on methylprednisolone. Improvement of clinical symptoms was seen on day 5 with a significant decrease in headache intensity. CLINICAL DISCUSSION: The article summarizes data from cases reported in the literature and our case to highlight coronavirus as a new trigger of lymphocytic hypophysitis. Despite the rarity of this complication, patients with a suspicion of hypophysitis after a recent COVID-19 infection should be carefully evaluated. CONCLUSION: COVID-19 infection can cause lymphocytic hypophysitis. However, it seems premature to conclude on the causal link between COVID-19 and endocrine diseases. Further studies on larger samples are needed to comprehend the pathogenesis of autoimmune endocrinopathies after COVID-19 infection.

Transient Central Diabetes Insipidus (Arginine Vasopressin Deficiency) Following SARS-CoV-2 Vaccination: A Case Report and Literature Review.

INTRODUCTION: Since December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected millions of people, causing the COVID-19 global pandemic. The use of novel technologies led to the development of different types of SARS-CoV-2 vaccines that have reduced severe disease courses and related deaths. Besides the positive impact of vaccination on the pandemic, local and systemic side effects have been reported; they are usually mild to moderate, although also serious adverse events have been described. CASE PRESENTATION: A 21-year-old female was referred to our hospital for the recent onset of severe polyuria and polydipsia, with the need for about 8 liters of daily water intake. The symptoms developed seven days after the administration of the second dose of the mRNA-based (Pfizer-BioNTech® BNT162b2) SARS-CoV-2 vaccine. In the suspicion of central diabetes insipidus (DI) development, she started treatment with desmopressin (Minirin® tablets) 60 mg/day with an improvement of symptoms and thirst. A thickening of the pituitary stalk was observed at the pituitary MRI with loss of the posterior pituitary bright spot on T1 weighted images. To confirm the diagnosis of central DI, both the water deprivation test and arginine stimulated copeptin test were performed; whilst the former gave no clear-cut indication of DI, the latter showed a reduced copeptin peak after arginine infusion consistent with the diagnosis of partial central DI. Furthermore, the development of symptoms right after the second dose of the vaccine strengthened the hypothesis that DI was related to the vaccination itself. After our evaluation, there was a progressive reduction of desmopressin dose to a complete discontinuation with the maintenance of a normal hydroelectrolytic balance. Clinical and biochemical follow-up was performed by repeating a pituitary MRI and a second arginine-stimulated copeptin test 15 months after the diagnosis. This time, copeptin levels reached a significantly higher peak after arginine stimulation that completely excluded central DI and at pituitary MRI, the thickening of the pituitary stalk previously described was no longer visible. CONCLUSION: Neurohypophysitis can have an abrupt onset independently of the etiology. Central DI is a rather exceptional event after SARS-CoV-2 vaccination but should be recalled in case of sudden polyuria and polydipsia. DI is indeed reported even after SARS-CoV-2 infection, thus, this report should not discourage the use of mRNA-based vaccines. Furthermore, our case demonstrates that full recovery of posterior pituitary function is possible after immunization with anti-Covid-19 BNT162b2 vaccine. Further studies are needed to clarify the possible mechanism relating to SARS-CoV-2 vaccination and this rare adverse event.

Successful treatment of medically and surgically refractory lymphocytic hypophysitis with fractionated stereotactic radiotherapy: a single-center experience and systematic literature review.

PURPOSE: To explore the potential role of focused radiotherapy in managing the lymphocytic hypophysitis (LH) refractory to medical therapy and surgery. METHOD: A systematic literature review was conducted following PRISMA guidelines to identify the studies on radiation treatment for hypophysitis, along with the experience in our institution. RESULTS: The study included eight patients, three from our institution and five from existing literature. The age at presentation ranged from 37 to 75 years old, with a median age of 58. The presenting symptoms involved headache in seven patients and diplopia in two patients. Pre-radiation visual field defects were noticed in four patients. All patients exhibited variable degrees of hypopituitarism before radiation, with oral corticosteroids being the initial medical treatment. Immunosuppressive therapy was attempted in two patients prior to radiation. Seven patients had a history of transsphenoidal surgery with a histologically confirmed LH. Three patients underwent stereotactic radiosurgery (SRS), while the remaining received FSRT, with a mean irradiation volume of 2.2 cm3. A single-session total dose of 12 -15 Gy was administered in the SRS group. In the FSRT group, doses ranged from 24 to 30 Gy with a median dose of 25 Gy, delivered in 2 Gy fractions. Four patients achieved a resolution of visual field defects, while another two patients demonstrated improvement in their associated focal neurologic deficits. No change in pre-existing endocrine status was shown after radiation, except in one patient. Clinical response was achieved in seven patients after a single course of radiation, while one patient required the second course. Six patients remained stable on low-dose glucocorticoid during at least a 12-month follow-up period, and one discontinued it entirely without experiencing relapse. Three patients demonstrated a complete radiologic response, while the remaining showed a partial radiologic response. CONCLUSIONS: Focused radiation, including FSRT, can play a role in symptomatic relief, effective mass shrinkage, and minimizing radiation exposure to critical surrounding structures in patients with refractory LH. However, further research efforts are necessary to better clarify its effects and optimal dose planning.

Secondary xanthogranulomatous hypophysitis mimicking a pituitary macroadenoma: a case report.

Hypophysitis is an extremely rare inflammatory disease that can mimic the clinical and radiological features of a pituitary adenoma. In this case report, we describe a 45-year-old woman with secondary xanthogranulomatous hypophysitis (XGH) who presented with signs of a pituitary macroadenoma. The patient complained of headaches, visual impairment, and amenorrhea-galactorrhea syndrome. Her physical examination was normal. Laboratory investigation revealed corticotropin, thyrotropin, and gonadotropin deficiencies. She also had low visual acuity in her right eye and an altered visual field. Pituitary magnetic resonance imaging revealed an intra and suprasellar mass measuring 13 × 11 × 16 mm, with hemorrhagic necrosis, that was having a discrete mass effect on the patient's optic chiasm and pituitary stalk. The patient was treated with hydrocortisone and levothyroxine, and then transferred to the Neurosurgery department for total transsphenoidal resection of the mass. Histological examination of the tumor permitted a diagnosis of XGH of a remodeled Rathke's pouch cyst to be made. Systemic conditions such as tuberculosis, sarcoidosis, and other granulomatous diseases were excluded. The etiopathogenesis of XGH remains poorly characterized, but it may be a progressive form of lymphocytic hypophysitis or a remodeled Rathke's pouch cyst. Screening for autoimmune pathology and systemic diseases is essential to guide appropriate management.

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.

Nothing Great Comes Without Its Risks: A Rare Case of Pembrolizumab-Induced Hypophysitis.

Pembrolizumab is an immune checkpoint inhibitor that targets the programmed cell death protein 1 and enhances immune activity against cancer cells. This has emerged as a powerful tool in the treatment of cancer in patients with severe metastatic disease. Despite this, immune checkpoint inhibitors are associated with many immune-related adverse effects. Reported endocrinopathies include thyroid dysfunction, insulin-deficient diabetes mellitus, primary adrenal insufficiency, and hypophysitis. Hypophysitis is more commonly associated with cytotoxic T-lymphocyte associated antigen 4 inhibitors like ipilimumab and rarely with pembrolizumab. A high clinical suspicion is needed to pursue a diagnosis of immune checkpoint inhibitorinduced hypophysitis, and prompt diagnosis is of immense importance due to the potentially life-threatening nature of endocrinopathies. We present a case of a 64-year-old Caucasian male individual undergoing treatment with pembrolizumab for undifferentiated lung carcinoma who subsequently developed hypophysitis.

Imaging for assessment of cancer treatment response to immune checkpoint inhibitors can be complementary in identifying hypophysitis.

Introduction: Hypophysitis is reported in 8.5%-14% of patients receiving combination immune checkpoint inhibition (cICI) but can be a diagnostic challenge. This study aimed to assess the role of routine diagnostic imaging performed during therapeutic monitoring of combination anti-CTLA-4/anti-PD-1 treatment in the identification of hypophysitis and the relationship of imaging findings to clinical diagnostic criteria. Methods: This retrospective cohort study identified patients treated with cICI between January 2016 and January 2019 at a quaternary melanoma service. Medical records were reviewed to identify patients with a documented diagnosis of hypophysitis based on clinical criteria. Available structural brain imaging with magnetic resonance imaging (MRI) or computed tomography (CT) of the brain and 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography with computed tomography (FDG-PET/CT) were assessed retrospectively. The main radiological outcome measures were a relative change in pituitary size or FDG uptake temporally attributed to cICI. Results: There were 162 patients (median age 60 years, 30% female) included. A total of 100 and 134 had serial CT/MRI of the brain and FDG-PET/CT, respectively. There were 31 patients who had a documented diagnosis of hypophysitis and an additional 20 who had isolated pituitary imaging findings. The pituitary gland enlargement was mild, and the largest absolute gland size was 13 mm, with a relative increase of 7 mm from baseline. There were no cases of optic chiasm compression. Pituitary enlargement and increased FDG uptake were universally transient. High-dose glucocorticoid treatment for concurrent irAEs prevented assessment of the pituitary-adrenal axis in 90% of patients with isolated imaging findings. Conclusion: Careful review of changes in pituitary characteristics on imaging performed for assessment of therapeutic response to iICI may lead to increased identification and more prompt management of cICI-induced hypophysitis.