Hypophysitis Secondary to Cytotoxic T-Lymphocyte-Associated Protein 4 Blockade: Insights into Pathogenesis from an Autopsy Series.

Hypophysitis that develops in cancer patients treated with monoclonal antibodies blocking cytotoxic T-lymphocyte-associated protein 4 (CTLA-4; an inhibitory molecule classically expressed on T cells) is now reported at an incidence of approximately 10%. Its pathogenesis is unknown, in part because no pathologic examination of the pituitary gland has been reported to date. We analyzed at autopsy the pituitary glands of six cancer patients treated with CTLA-4 blockade, one with clinical and pathologic evidence of hypophysitis, one with mild lymphocytic infiltration in the pituitary gland but no clinical signs of hypophysitis, and four with normal pituitary structure and function. CTLA-4 antigen was expressed by pituitary endocrine cells in all patients but at different levels. The highest levels were found in the patient who had clinical and pathologic evidence of severe hypophysitis. This high pituitary CTLA-4 expression was associated with T-cell infiltration and IgG-dependent complement fixation and phagocytosis, immune reactions that induced an extensive destruction of the adenohypophyseal architecture. Pituitary CTLA-4 expression was confirmed in a validation group of 37 surgical pituitary adenomas and 11 normal pituitary glands. The study suggests that administration of CTLA-4 blocking antibodies to patients who express high levels of CTLA-4 antigen in the pituitary can cause an aggressive (necrotizing) form of hypophysitis through type IV (T-cell dependent) and type II (IgG dependent) immune mechanisms.

The beneficial effect of acromegaly control on blood pressure values in normotensive patients.

OBJECTIVE: Control of acromegaly may ameliorate blood pressure (BP) in hypertensive (HT) patients. We evaluated the impact of acromegaly control on BP values of normotensive (NT) acromegalics. DESIGN: Retrospective cohort study. PATIENTS: Fifty-eight naïve patients with acromegaly (39 F; age range, 30-69 years), including 28 NT and 30 HT subjects, participated in the study. MEASUREMENTS: Blood pressure was measured by clinical measurement and 24-h ambulatory monitoring at diagnosis and after 24 months of medical therapy for acromegaly. RESULTS: Acromegaly was controlled by medical therapy in 15 NT and 17 HT patients at 24 months. In the NT group, systolic (SBP) or diastolic (DBP) BP significantly increased (all P < 0·005) when acromegaly was uncontrolled, but did not change when the disease was controlled. Changes in SBP and DBP were also significantly different between uncontrolled and controlled NT patients. At 24 months, clinical hypertension was detected only in uncontrolled NT patients (46% vs 0%, P < 0·001), whereas ambulatory hypertension was found in 38% of uncontrolled and in 7% of controlled NT subjects (P = 0·035). In the HT group, ambulatory SBP increased in patients with uncontrolled acromegaly (24-h SBP P = 0·046, day SBP P = 0·005, night SBP P = 0·005), whereas ambulatory DBP decreased in subjects with controlled disease (24-h DBP P = 0·008, day DBP P = 0·026). CONCLUSIONS: Control of acromegaly has a beneficial effect on BP regulation either in HT or NT subjects; in the latter, it may prevent progression towards hypertension.

Hashimoto's thyroiditis in a benign cystic teratoma of the ovary: case report and literature review.

Ectopic thyroid tissue in ovarian teratoma or in struma ovarii appears to be histologically identical to the thyroid gland tissue and may virtually exhibit all the pathological patterns found in the thyroid gland. However, the concurrent lymphocytic infiltration of the thyroid gland, as found in Hashimoto's thyroiditis, and of the ectopic thyroid tissue is extremely rare. We describe the case of an 18-years old patient, in which a right ovarian 4 cm cyst has been found during pelvic ultrasound exam. The cyst was resected and microscopic examination of the mass revealed a mature cystic teratoma in which epidermal-like lining with skin adnexa, admixed with respiratory type epithelium, and areas of mature fatty, chondroid and dentigerous tissues were found. In a peripheral area of 0.7 cm  × â€Š0.5 cm, a prominent lymphocytic infiltrate surrounding thyroid follicles was identifiable. Thyroid function evaluation at different time points after surgery, revealed the development of mild hypothyroidism. Anti-TPO and anti-Tg autoantibodies were elevated, at fine needle aspiration biopsy a lymphocytic infiltrate, compatible with Hashimoto's thyroiditis, was present. We report here a rare case of Hashimoto's thyroiditis occurring both in the thyroid and in the ectopic thyroid tissue in the context of a benign cystic teratoma of the ovary.

Steroid treatment in the management of destructive thyrotoxicosis induced by PD1 blockade.

Objective: Destructive thyroiditis is the most common endocrine immune-related adverse event (iRAEs) in patients treated with anti-PD1/PD-L1 agents. Given its self-limited course, current guidelines recommend no treatment for this iRAE. Nevertheless, in patients with enlarged thyroid volume and a poor performance status, thyrotoxicosis may be particularly severe and harmful. The aim of the study is to evaluate if steroid treatment might be useful in improving thyrotoxicosis in subjects with a poor performance status. Methods: We conducted a retrospective study, comparing the course of thyrotoxicosis of four patients treated with oral prednisone at the dosage of 25 mg/day (tapered to discontinuation in 3 weeks) and an enlarged thyroid volume to that of eight patients with similar thyroid volume who were left untreated. Results: The levels of thyroid hormones were lower in subjects treated compared to those untreated at time of 7, 14, 21, 28, 35, 42, 60 and 90 days (P < 0.05 at each time). The time to remission of thyrotoxicosis was 24 days in patients treated with steroids and 120 days in untreated patients (P < 0.001). At 6 months, the rate of evolution to hypothyroidism was similar in the two groups (4/4 in the steroid group vs 7/8 in the untreated group, P = 0.74) and no difference was found in tumor progression (P = 0.89). Conclusions: Our preliminary data suggest that in patients with a poor performance status experiencing a severe destructive thyrotoxicosis induced by PD-1 blockade, a short period of administration of oral prednisone is effective in obtaining a quick reduction of the levels of thyroid hormones.

Endocrine-related adverse conditions in patients receiving immune checkpoint inhibition: an ESE clinical practice guideline.

Immune checkpoint inhibitors (ICI) have revolutionized cancer treatment but are associated with significant autoimmune endocrinopathies that pose both diagnostic and treatment challenges. The aim of this guideline is to provide clinicians with the best possible evidence-based recommendations for treatment and follow-up of patients with ICI-induced endocrine side-effects based on the Grading of Recommendations Assessment, Development, and Evaluation system. As these drugs have been used for a relatively short time, large systematic investigations are scarce. A systematic approach to diagnosis, treatment, and follow-up is needed, including baseline tests of endocrine function before each treatment cycle. We conclude that there is no clear evidence for the benefit of high-dose glucocorticoids to treat endocrine toxicities with the possible exceptions of severe thyroid eye disease and hypophysitis affecting the visual apparatus. With the exception of thyroiditis, most endocrine dysfunctions appear to be permanent regardless of ICI discontinuation. Thus, the development of endocrinopathies does not dictate a need to stop ICI treatment.

Pituitary and systemic autoimmunity in a case of intrasellar germinoma.

Germinomas arising in the sella turcica are difficult to differentiate from autoimmune hypophysitis because of similar clinical and pathological features. This differentiation, nevertheless, is critical for patient care due to different treatments of the two diseases. We report the case of an 11-year-old girl who presented with diabetes insipidus and growth retardation, and was found to have an intra- and supra-sellar mass. Initial examination of the pituitary biopsy showed diffuse lymphocytic infiltration of the adenohypophysis and absent placental alkaline phosphatase expression, leading to a diagnosis of hypophysitis and glucocorticoid treatment. Because of the lack of clinical and radiological response, the pituitary specimen was re-examined, revealing this time the presence of scattered c-kit and Oct4 positive germinoma cells. The revised diagnosis prompted the initiation of radiotherapy, which induced disappearance of the pituitary mass. Immunological studies showed that the patient's serum recognized antigens expressed by the patient's own germinoma cells, as well as pituitary antigens like growth hormone and systemic antigens like the Sjögren syndrome antigen B and alpha-enolase. The study first reports the presence of pituitary and systemic antibodies in a patient with intrasellar germinoma, and reminds us that diffuse lymphocytic infiltration of the pituitary gland and pituitary antibodies does not always indicate a diagnosis of autoimmune hypophysitis.

Management of Thyrotoxicosis Induced by PD1 or PD-L1 Blockade.

CONTEXT: Thyrotoxicosis is a common immune-related adverse event in patients treated with programmed cell death protein-1 (PD1) or programmed cell death protein ligand-1 (PD-L1) blockade. A detailed endocrinological assessment, including thyroid ultrasound and scintigraphy, is lacking, as are data on response to treatment and follow-up. OBJECTIVE: The aim of this study was to better characterize the thyrotoxicosis secondary to immune checkpoint inhibitors, gaining insights into pathogenesis and treatment. METHODS: We conducted a retrospective study of 20 consecutive patients who had normal thyroid function before starting immunotherapy and then experienced thyrotoxicosis on PD1 or PD-L1 blockade. Clinical assessment was combined with thyroid ultrasound, 99mtechnecium scintiscan, and longitudinal thyroid function tests. RESULTS: Five patients had normal or increased scintigraphic uptake (Sci+), no serum antibodies against the thyrotropin receptor, and remained hyperthyroid throughout follow-up. The other 15 patients had no scintigraphic uptake (Sci-) and experienced destructive thyrotoxicosis followed by hypothyroidism (N = 9) or euthyroidism (N = 6). Hypothyroidism was more readily seen in those with normal thyroid volume than in those with goiter (P = .04). Among Sci- individuals, a larger thyroid volume was associated with a longer time to remission (P < .05). Methimazole (MMI) was effective only in Sci+ individuals (P < .05). CONCLUSION: Administration of PD1- or PD-L1-blocking antibodies may induce 2 different forms of thyrotoxicosis that appear similar in clinical severity at onset: a type 1 characterized by persistent hyperthyroidism that requires treatment with MMI, and a type 2, characterized by destructive and transient thyrotoxicosis that evolves to hypothyroidism or euthyroidism. Thyroid scintigraphy and ultrasound help in differentiating and managing these 2 forms of iatrogenic thyrotoxicosis.

Activating Antibodies to The Calcium-sensing Receptor in Immunotherapy-induced Hypoparathyroidism.

CONTEXT: Immune checkpoint inhibitors (ICIs), such as programmed cell death protein-1 (PD-1), programmed cell death protein-ligand 1 (PD-L1), and cytotoxic T lymphocyte antigen-4 (CTLA-4) monoclonal antibodies, are approved for the treatment of some types of advanced cancer. Their main treatment-related side-effects are immune-related adverse events (irAEs), especially thyroid dysfunction and hypophysitis. Hypoparathyroidism, on the contrary, is an extremely rare irAE. OBJECTIVES: The aim of the study was to investigate the etiology of autoimmune hypoparathyroidism in a lung cancer patient treated with pembrolizumab, an anti-PD-1. METHODS: Calcium-sensing receptor (CaSR) autoantibodies, their functional activity, immunoglobulin (Ig) subclasses and epitopes involved in the pathogenesis of autoimmune hypoparathyroidism were tested. RESULTS: The patient developed hypocalcemia after 15 cycles of pembrolizumab. Calcium levels normalized with oral calcium carbonate and calcitriol and no remission of hypocalcemia was demonstrated during a 9-month follow-up. The patient was found to be positive for CaSR-stimulating antibodies, of IgG1 and IgG3 subclasses, that were able to recognize functional epitopes on the receptor, thus causing hypocalcemia. CONCLUSION: The finding confirms that ICI therapy can trigger, among other endocrinopathies, hypoparathyroidism, which can be caused by pathogenic autoantibodies.

Firm mass in thyroid of an elderly patient: not always cancer.

SUMMARY: In elderly patients presenting with a solid thyroid mass, the differential diagnosis between benign and malignant lesion is not always straightforward. We present the case of an 85-year-old woman with fever and an enlarged, firm and painful thyroid mass. Blood exams documented a mild thyrotoxicosis with a moderate inflammatory status. Thyroid scintiscan showed an absent uptake of 131I. Ultrasound and CT scan documented a 3 cm hypoechoic nodule with infiltration of the sternocleidomastoid muscle, very suspicious for neoplastic nature. Fine-needle aspiration and tru-cut biopsy were performed. During biopsy, the lesion was partially drained and a brownish fluid was extracted. The culture resulted positive for Klebsiella pneumoniae whereas the pathological analysis of the specimen was not conclusive due to the presence of an intense inflammatory response. A targeted oral antibiotic therapy was then initiated, obtaining only a partial response thus, in order to achieve a definite diagnosis, a minimally invasive hemithyroidectomy was performed. The pathological analysis documented acute suppurative thyroiditis and the clinical conditions of the patient significantly improved after surgical removal of thyroid abscess. In elderly patients with a solid thyroid mass, although neoplastic origin is quite frequent, acute suppurative thyroiditis should be considered as a differential diagnosis. LEARNING POINTS: A solid and rapidly growing thyroid mass in elderly patients can hide a multifaceted variety of diseases, both benign and malign. A multidisciplinary team (endocrinologist, surgeon, radiologist and pathologist) could be necessary in order to perform a correct differential diagnosis and therapeutic approach. Surgery can be decisive not only to clarify a clinically uncertain diagnosis, but also to rapidly improve the clinical conditions of the patient.

Hypophysitis induced by immune checkpoint inhibitors: a 10-year assessment.

Introduction: Hypophysitis caused by immune checkpoint inhibitors (ICIs) has risen to the medical attention during the past decade. ICIs are monoclonal antibodies that block the interaction between molecules that normally inhibit the function of effector T cells, ultimately increasing their ability to destroy cancer cells but also causing immune-related adverse events, such as hypophysitis. Ipilimumab, a CTLA-4 blocker, was the first ICI approved from the Food and Drug Administration for advanced melanoma patients in 2011. Several additional ICIs targeting CTLA-4, PD-1, or PD-L1 are now used in many clinical trials, making it important for physicians to recognize and treat hypophysitis adequately.Areas covered: This review will provide insights into the mechanisms of pituitary toxicity, highlight the complexity of clinical phenotypes of ICI hypophysitis, and offer practical recommendations.Expert opinion: ICI hypophysitis differs in many respects from primary hypophysitis, and also according to the type of ICI that caused it. Its pathogenesis remains unknown, although the expression of CTLA-4 and PD-1 on pituitary cells could play a role. The diagnosis is mainly clinical since there are no specific serological markers and MRI findings are subtle. The treatment is based on long-term hormone replacement and does not typically require discontinuation of immunotherapy.

Immune Checkpoint Blockade Anti-PD-L1 as a Trigger for Autoimmune Polyendocrine Syndrome.

CONTEXT: The programmed cell death protein 1 (PD-1)/programmed cell death protein ligand 1 (PD-L1) pathway is a key regulator in T-cell activation and tolerance, limiting effector T-cell function in peripheral tissues. Atezolizumab, an anti-PD-L1 monoclonal antibody, is approved for treatment of some types of advanced cancer. Its main treatment-related adverse events are immune related, such as thyroid dysfunction and hypophysitis. Autoimmune endocrinopathy can occur as isolated manifestations; only a few cases of autoimmune polyendocrine syndromes have been reported thus far. CASE: We report a case of polyendocrine syndrome type 2, characterized by Addison disease (AD), type 1 diabetes mellitus (T1DM), accompanied by hypophysitis, in a patient treated with atezolizumab. Testing was positive for 21-hydroxylase and pituitary antibodies and negative for islet cells antibodies. HLA typing revealed DRB1*04 and DQB1*03 haplotypes, which are associated with increased susceptibility to T1DM and AD. CONCLUSION: The type and severity of immune-related adverse events in polyendocrine syndrome type 2 are different and depend on the monoclonal antibody used. Although the numerous molecular mechanisms inducing autoimmune endocrine diseases are still unclear, a link exists between HLA haplotypes, gene variants involved in immune checkpoint molecule expression, and increased susceptibility to autoimmune endocrinopathies. Additional studies are needed to identify susceptible patients and adapt therapy to each patient.

Diabetes mellitus induced by somatostatin analogue therapy is not permanent in acromegalic patients.

CONTEXT: Therapy with somatostatin analogues (SSAs) may have deleterious effects on glucose metabolism in patients with acromegaly, often leading to the development of diabetes mellitus (DM). AIM: The aim of the study was to evaluate whether DM, developed during therapy with SSAs, may revert after drug withdrawal and cure of acromegaly with pituitary adenomectomy. DESIGN: Retrospective cohort study, in a tertiary referral centre. PATIENTS: Eighteen acromegalic patients without DM at the diagnosis of acromegaly treated with SSAs as a primary therapy, and then cured by pituitary adenomectomy. METHODS: Endocrine status and glucose homeostasis were evaluated at diagnosis of acromegaly and at least every 6 months during SSA therapy. At each visit, patients were classified into one of the following classes: normal glucose tolerance, prediabetes, overt diabetes. RESULTS: Median follow-up after starting SSAs therapy was 69 months (IQR 54.75-132.25). During SSA therapy, all patients had controlled acromegaly defined by normal serum IGF1 concentrations for the age. Of the 13 euglycaemic patients at diagnosis, three developed prediabetes and three diabetes, whereas, of the five prediabetic patients at diagnosis, two worsened to overt diabetes and three remained in the prediabetic range (P = 0.04). After curing acromegaly with pituitary adenomectomy and subsequent SSA withdrawal, prediabetes reverted in five of six patients, and diabetes in all five patients (three reverted to euglycaemia, while two reverted to prediabetes) (P = 0.01). CONCLUSIONS: In acromegalic patients with controlled disease, changes in glycaemic status induced by SSAs are not permanent.

Graves' Disease Induced by Immune Checkpoint Inhibitors: A Case Report and Review of the Literature.

INTRODUCTION: In the last few years, immune checkpoint inhibitors (ICPis) have become a common treatment of cancer. ICPis are associated with peculiar immune side effects, termed immune-related adverse events (irAEs). Thyroid disfunction is a common irAE, but clinical manifestation, severity, and pathogenesis can be variable. While destructive thyroiditis and hypothyroidism are the most common thyroid irAEs induced by ICPis, autoimmune hyperthyroidism (Graves' disease) is rare. We describe a case of a Graves' disease induced by anti-PD-1 therapy and we review the previous reports on this issue. CASE PRESENTATION: A 51-year-old man developed an overt autoimmune hyperthyroidism 2 months after he had started nivolumab (anti-PD-1) therapy for a metastatic non-small cell lung cancer. Although TSH-receptor autoantibodies (TRAb) were negative, the persistence of hyperthyroidism, the hypervascular pattern at thyroid ultrasound, and the high uptake at thyroid scintigraphy were all features suggestive of Graves' disease. Methimazole was started with the prompt restoration of euthyroidism. TRAb remained undetectable during the entire follow-up. CONCLUSIONS: Autoimmune hyperthyroidism can be induced by anti-PD-1 treatment. TRAb were negative in both cases of nivolumab-induced Graves' disease described to date. A correct differential diagnosis between destructive thyroiditis and autoimmune hyperthyroidism is crucial for the appropriate treatment.

Clinical heterogeneity of hypophysitis secondary to PD-1/PD-L1 blockade: insights from four cases.

SUMMARY: Programmed cell death protein 1/programmed cell death protein ligand 1 (PD-1/PD-L1) and cytotoxic T-lymphocyte antigen 4/B7 (CTLA-4/B7) pathways are key regulators in T-cell activation and tolerance. Nivolumab, pembrolizumab (PD-1 inhibitors), atezolizumab (PD-L1 inhibitor) and ipilimumab (CTLA-4 inhibitor) are monoclonal antibodies approved for treatment of several advanced cancers. Immune checkpoint inhibitors (ICIs)-related hypophysitis is described more frequently in patients treated with anti-CTLA-4; however, recent studies reported an increasing prevalence of anti-PD-1/PD-L1-induced hypophysitis which also exhibits slightly different clinical features. We report our experience on hypophysitis induced by anti-PD-1/anti-PD-L1 treatment. We present four cases, diagnosed in the past 12 months, of hypophysitis occurring in two patients receiving anti-PD-1, in one patient receiving anti-PD-1 and anti-CTLA-4 combined therapy and in one patient receiving anti-PD-L1. In this case series, timing, clinical presentation and association with other immune-related adverse events appeared to be extremely variable; central hypoadrenalism and hyponatremia were constantly detected although sellar magnetic resonance imaging did not reveal specific signs of pituitary inflammation. These differences highlight the complexity of ICI-related hypophysitis and the existence of different mechanisms of action leading to heterogeneity of clinical presentation in patients receiving immunotherapy. LEARNING POINTS: PD-1/PD-L1 blockade can induce hypophysitis with a different clinical presentation when compared to CTLA-4 blockade. Diagnosis of PD-1/PD-L1 induced hypophysitis is mainly made on clinical grounds and sellar MRI does not show radiological abnormalities. Hyponatremia due to acute secondary adrenal insufficiency is often the principal sign of PD-1/PD-L1-induced hypophysitis and can be masked by other symptoms due to oncologic disease. PD-1/PD-L1-induced hypophysitis can present as an isolated manifestation of irAEs or be in association with other autoimmune diseases.

Autoimmune hypophysitis of SJL mice: clinical insights from a new animal model.

Autoimmune hypophysitis (AH) is a rare but increasingly recognized disease of the pituitary gland. Its autoantigens are unknown, and the management is difficult because it is often misdiagnosed as a nonsecreting adenoma. By immunizing female SJL/J mice with mouse pituitary extracts, we established a new mouse model of experimental AH. Immunized mice developed severe lymphocytic infiltration in the anterior pituitary that closely mimicked the human pathology. In the early phase of experimental AH, the pituitary enlarged, consistent with the compression symptoms reported by hypophysitis patients at presentation. In the florid phase, adrenal insufficiency and pituitary antibodies developed, in strong correlation with the pituitary pathology. In the late phase, hypothyroidism ensued, and the pituitary gland became atrophic. Using immune sera as probes in a two-dimensional immunoblotting screen followed by mass spectrometry, we identified several proteins that could function as pituitary autoantigens. These findings provide new insights into the pathogenesis of AH, and establish a platform for developing novel diagnostic biomarkers and therapeutics.

Pituitary autoimmunity: 30 years later.

Pituitary autoimmunity encompasses a spectrum of conditions ranging from histologically proven forms of lymphocytic hypophysitis to the presence of pituitary antibodies in apparently healthy subjects. Hypophysitis is a rare but increasingly recognized disorder that typically presents as a mass in the sella turcica. It mimics clinically and radiologically other non-functioning sellar masses, such as the more common pituitary adenoma. Hypophysitis shows a striking temporal association with pregnancy, and it has been recently described during immunotherapies that block CTLA-4. Several candidate pituitary autoantigens have been described in the last decade, although none has proven useful as a diagnostic tool. This review summarizes the advances made in the field since the publication of the first review on pituitary autoimmunity, and the challenges that await clarification.

Novel autoantigens in autoimmune hypophysitis.

BACKGROUND: Pituitary autoantibodies are found in autoimmune hypophysitis and other conditions. They are a marker of pituitary autoimmunity but currently have limited clinical value. The methods used for their detection lack adequate sensitivity and specificity, mainly because the pathogenic pituitary autoantigen(s) are not known and therefore antigen-based immunoassays have not been developed. OBJECTIVES: This study aimed to identify novel pituitary autoantigens using sera as probes in proteomic assays. We also compared immunoblotting and immunofluorescence methods for their accuracy in diagnosing autoimmune hypophysitis. STUDY DESIGN AND SUBJECTS: Twenty-eight sera from autoimmune hypophysitis cases (14 histologically proven and 14 clinically suspected) were compared to 98 sera from controls, which included 14 patients with pituitary adenomas, 48 with autoimmune thyroiditis (15 Graves' disease and 33 Hashimoto's thyroiditis) and 36 healthy subjects. METHODS: All sera were tested against human pituitary cytosolic proteins separated by one-dimensional (1D) gel electrophoresis. The band recognition was analysed statistically to detect molecular weight regions preferentially recognized by hypophysitis sera. 2D gel immunoblotting and mass spectrometry were then used to sequence the protein spots of interest. Sera were also tested by immunofluorescence for their recognition of Macaca mulatta pituitary sections. RESULTS: A single region in the 25-27-kDa range was recognized more often by hypophysitis cases than healthy subjects (P = 0.004) or patients with pituitary adenomas (P = 0.044). This region contained two novel candidate autoantigens: chromosome 14 open reading frame 166 (C14orf166) and chorionic somatomammotrophin. Immunoblotting positivity for the 25-27-kDa region yielded greater sensitivity (64%vs. 57%) and specificity (86%vs. 76%) than immunofluorescence in predicting histologically proven hypophysitis, although the performance was still inadequate to make immunoblotting a clinically useful test. CONCLUSION: The study reports two novel proteins that could act as autoantigens in autoimmune hypophysitis. Further studies are needed to validate their pathogenic role and diagnostic utility.

Persisting Embryonal Infundibular Recess (PEIR): Two Case Reports and Systematic Literature Review.

Context: The persisting embryonal infundibular recess (PEIR) is a rare anomaly of the floor of the third ventricle with a debated pathogenesis. It can be a cause of misdiagnosis in the case of cystic lesions of the sellar and suprasellar area. Objective: To describe two recently evaluated cases and provide a systematic literature review. Evidence Acquisition and Case Descriptions: PEIR has been previously reported in six adult patients. Because in some cases it was associated with hydrocephalus and/or empty sella, a possible role of altered intracranial pressure in PEIR formation has been postulated. We evaluated two female patients, aged 34 and 50 years, referred to the Pituitary Surgery Clinic of the University of Brescia with the diagnosis of a sellar cyst and craniopharyngioma, respectively. Endocrine screening and visual field testing were normal. No signs of hydrocephalus or empty sella, as well as other indirect signs of intracranial hypertension, were visible on MRI scans. After a multidisciplinary reevaluation, diagnosis of PEIR was made in both cases. Both patients are followed but have not developed any disturbance related to the PEIR in the following 18 months. Conclusions: PEIR is a rare condition, probably unrecognized and the result of dysembriogenesis, which should be included in the differential diagnosis of cystic sellar lesions. Imaging features (funnel pituitary stalk and cyst in the sella) appear pathognomonic. A normal endocrine evaluation might help in the diagnosis and warrants conservative treatment.

Prevalence and functional significance of antipituitary antibodies in patients with autoimmune and non-autoimmune thyroid diseases.

BACKGROUND: Circulating antipituitary antibodies (APA) are markers of autoimmune hypophysitis, which may cause deficient pituitary function. The prevalence of APA in autoimmune thyroid disorders (AITD) is uncertain. OBJECTIVES: The aims of this study were 1) to evaluate APA prevalence in a large series of patients with AITD and non-AITD and 2) to investigate the functional significance of APA by assessing pituitary function in APA-positive patients. DESIGN AND SETTING: We conducted a health survey on consecutive AITD and non-AITD patients at a tertiary referral center (Department of Endocrinology, Pisa). PATIENTS: Subjects, including 1290 consecutive patients with thyroid disorders (961 AITD and 329 non-AITD) and 135 controls, were enrolled in the study. METHODS: APA (indirect immunofluorescence), free T(4), free T(3), TSH, and organ-specific autoantibodies were assayed in all patients. Functional pituitary evaluation was performed in most APA-positive patients. RESULTS: APA frequency was higher in AITD (11.4%) than in non-AITD (0.9%; P < 0.0001) patients; all control subjects had negative APA tests. APA were more frequently found in Hashimoto's thyroiditis (13%) than in Graves' disease (7.1%; P = 0.05). Of 110 APA-positive AITD patients, 20 (18.2%) had autoimmune polyglandular syndrome, whereas 90 (81.8%) had apparently isolated AITD. APA positivity increased percentage of autoimmune polyglandular syndrome in our series from 10.4 to 13.5%. Of 110 APA-positive patients, 102 were submitted to dynamic testing for functional pituitary assessment; 36 patients (35.2%) had mild or severe GH deficiency (GHD). No additional anterior pituitary hormone deficiencies were found; one patient had central diabetes insipidus. Pituitary abnormalities at magnetic resonance imaging were found in most APA-positive GHD patients. CONCLUSIONS: APA are frequently present in patients with AITD. Patients should be tested for APA because positive tests are associated with GHD.

Diabetes insipidus is an unfavorable prognostic factor for response to glucocorticoids in patients with autoimmune hypophysitis.

INTRODUCTION: Autoimmune hypophysitis (AH) has a variable clinical presentation and natural history; likewise, its response to glucocorticoid therapy is often unpredictable. OBJECTIVE: To identify clinical and radiological findings associated with response to glucocorticoids. DESIGN AND METHODS: 12 consecutive patients with AH, evaluated from 2008 to 2016. AH was the exclusion diagnosis after ruling out other pituitary masses and secondary causes of hypophysitis. Mean follow-up time was 30 ± 27 months (range 12-96 months). RESULTS: MRI identified two main patterns of presentation: global enlargement of the pituitary gland or panhypophysitis (n = 4, PH), and pituitary stalk abnormality only, or infundibulo-neuro-hypophysitis (n = 8, INH). Multiple tropin defects were more common in PH (100%) than those in INH (28% P = 0.014), whereas diabetes insipidus was more common in INH (100%) than that in PH (50%; P = 0.028). All 4 PH and 4 out of 8 INH were treated with glucocorticoids. Pituitary volume significantly reduced in all PH patients (P = 0.012), defective anterior pituitary function recovered only in the two patients without diabetes insipidus (50%) and panhypopituitarism persisted, along with diabetes insipidus, in the remaining 2 (50%). In all INH patients, either treated or untreated, pituitary stalk diameter reduced (P = 0.008) but diabetes insipidus persisted in all. CONCLUSIONS: Glucocorticoid therapy may improve anterior pituitary function in a subset of patients but has no effect on restoring posterior pituitary function. Diabetes insipidus appears as a negative prognostic factor for response to glucocorticoids.