Review on Recent Topics in Hypophysitis

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.

Inflammatory and Infectious Disorders in Endocrine Pathology

A variety of inflammatory conditions may directly involve the endocrine glands, leading to endocrine dysfunction that can cause severe consequences on patients' health, if left untreated. Inflammation of the endocrine system may be caused by either infectious agents or other mechanisms, including autoimmune and other immune-mediated processes. Not infrequently, inflammatory and infectious diseases may appear as tumor-like lesions of endocrine organs and simulate neoplastic processes. These diseases may be clinically under-recognized and not infrequently the diagnosis is suggested on pathological samples. Thus, the pathologist should be aware of the basic principles of their pathogenesis, as well as of their morphological features, clinicopathological correlates, and differential diagnosis. Interestingly, several systemic inflammatory conditions show a peculiar tropism to the endocrine system as a whole. In turn, organ-specific inflammatory disorders are observed in endocrine glands. This review will focus on the morphological aspects and clinicopathological features of infectious diseases, autoimmune disorders, drug-induced inflammatory reactions, IgG4-related disease, and other inflammatory disorders involving the endocrine system. A mixed entity-based and organ-based approach will be used, with the aim to provide the practicing pathologist with a comprehensive and practical guide to the diagnosis of infectious and inflammatory disorders of the endocrine system.

Paraneoplastic autoimmune hypophysitis: An emerging concept

Pituitary autoimmunity is one of the principal causes of hypopituitarism. Additionally, hypophysitis is one of the immune-related adverse events associated with immunotherapy. Recent case-oriented research has revealed a novel type of autoimmune hypophysitis, anti-PIT-1 hypophysitis, related to isolated adrenocorticotropic hormone (ACTH) deficiency and immune checkpoint inhibitor-related hypophysitis, as a form of paraneoplastic syndrome. Under these conditions, the ectopic expression of pituitary antigens present in tumors evokes a breakdown of immune tolerance, resulting in the production of autoantibodies and autoreactive cytotoxic T cells that specifically harm pituitary cells. Consequently, an innovative clinical entity of paraneoplastic autoimmune hypophysitis has been purported. This novel concept and its underlying mechanisms provide clues for understanding the pathogenesis of autoimmune pituitary diseases and can be applied to other autoimmune diseases. This review discusses the etiology of paraneoplastic autoimmune hypophysitis and its future.

Hypophysitis related to immune checkpoint inhibitors: An intriguing adverse event with many faces

INTRODUCTION

The incorporation of immune checkpoint inhibitors in the oncologists' arsenal is a milestone in cancer therapeutics, though not being devoid of toxicities.Areas covered: The present review provides a comprehensive and up-to-date overview of the immune-related hypophysitis with focus on the elusive biological background, the wide spectrum of the epidemiological profile, the varying clinical aspects, and the diagnostic and therapeutic challenges.Expert opinion: Historically considered distinctive of anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4) monoclonal antibodies (mAbs), the immune-related hypophysitis is increasingly correlated with the anti-programmed cell-death (PD) protein 1 (PD-1)/anti-PD ligand 1 (PD-L1) mAbs. The distinct phenotype of hypophysitis related to anti-PD1/anti-PD-L1 mAbs is highlighted with focus on the immune-related isolated adrenocorticotropic (ACTH) deficiency. The immune-related central diabetes insipidus is discussed as a rare aspect of anti-CTL-A4 mAbs-induced hypophysitis, recently related to anti-PD1/anti-PD-L1 mAbs as well. The present review builds on existing literature concerning immune-related hypophysitis underscoring the pending issues still to be addressed, including (i) pathogenesis; (ii) correlation with preexisting autoimmunity; (iii) predictive value; (iv) utility of high-dose glucocorticoids; and (v) establishment of evidence-based diagnostic and therapeutic protocols. Increased awareness and constant vigilance are advocated as cornerstone of a multidisciplinary approach to ensure optimal patients' care.

Magnetic resonance imaging of the hypothalamo-pituitary region

The diagnosis and management of mass lesions in the sellar and parasellar areas remain challenging. When approaching patients with possible sellar or hypothalamic masses, it is important not only to focus on imaging but also detect possible pituitary hormone deficits or excess, in order to establish an appropriate diagnosis and initiate treatment. The imaging modalities used to characterize hypothalamic and pituitary lesions have significantly evolved over the course of the past several years. Computed tomography (CT) and CT angiography play a major role in detecting various sellar lesions, especially in patients who have contraindications to magnetic resonance imaging (MRI) and can also yield important information for surgical planning. However, MRI has become the gold standard for the detection and characterization of hypothalamic and pituitary tumors, infections, cystic, or vascular lesions. Indeed, the imaging characteristics of hypothalamic and sellar lesions can help narrow down the differential diagnosis preoperatively. In addition, MRI can help establish the relationship of mass lesions to surrounding structures. A pituitary MRI examination should be obtained if there is concern for mass effect (including visual loss, ophthalmoplegia, headache) or if there is clinical suspicion and laboratory evidence of either hypopituitarism or pituitary hormone excess. The information obtained from MRI images also provides us with assistance in planning surgery. Using intraoperative MRI can be very helpful in assessing the adequacy of tumor resection. In addition, MRI images yield reliable data that allow for noninvasive monitoring of patients postoperatively.

Magnetic resonance imaging criteria of immune checkpoint inhibitor-induced hypophysitis

Autoimmune hypophysitis is a rare complication of immune checkpoint inhibitors. Immune checkpoint inhibitors have been used for advanced stages of melanoma, renal cell carcinoma, and lung cancer. Multiple endocrinopathies, among them hypophysitis, could result as a reverse event from this therapy. MRI is the imaging modality of choice and usually demonstrates pituitary gland hypertrophy, irregular thickening of the pituitary infundibulum, and diffuse enhancement. We present a case of stage IV metastatic renal cell carcinoma complicated with hypophysitis secondary to combined nivolumab and ipilimumab therapy.

Endocrine adverse events related with immune checkpoint inhibitors: an update for clinicians

Designated as scientific breakthrough of current decade, immune checkpoint inhibitors attenuate the cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and the programmed cell death 1 (PD-1)/ligand 1 (PD-L1) pathways, depriving cancer cells of a key strategy of evasion from immunosurveillance. The reinvigoration of immune response translates into clinical success, inevitably entwined with a novel constellation of immune-related adverse events. The present review dissects the endocrine immune-related adverse events, emphasizing their unique profile featured by unpredictable onset, irreversibility, nonspecific symptoms, wide clinical spectrum and sophisticated diagnostic work-up. Guidelines advocate individualized decision-making process guided by clinicians' judgement. Future perspective should be governed by five principles - prevention, anticipation, detection, treatment, monitoring - aiming to gain the optimal profit diminishing immunotoxicity.

Central Diabetes Insipidus Associated with Orbital Apex Syndrome

Orbital apex syndrome (OAS) manifests as multiple cranial nerve palsies caused by an abnormal nerve response to inflammation or other processes. Central diabetes insipidus (CDI) is characterized by deficient synthesis or secretion of antidiuretic hormone. A 62-year-old woman underwent myringotomy for otitis media with effusion. Two months after the procedure, symptoms of hearing loss had not improved, and she underwent left tympanoplasty and mastoidectomy. After surgery, she presented with left ocular pain and visual loss. Neurologic examination revealed ptosis, total ophthalmoplegia, and a relative afferent pupillary defect on the left eye. Magnetic resonance imaging showed an asymmetric contrast-enhancing lesion in the left orbital apex and left cavernous sinus, with adjacent dural thickening and enhancement. OAS was diagnosed, and steroid treatment was started. During the regular follow-up period, she reported polyuria, and CDI was diagnosed. Treatment with intranasal desmopressin 10 μg twice daily was started, and symptoms greatly improved. The mechanism underlying the association of CDI with OAS is unclear, and further research is needed. The present case suggests that polyuria in OAS should alert neurologists and ophthalmologists to possible CDI.

Primary hypophysitis: Experience of a Single Tertiary Center

PURPOSE

The authors review the clinical outcomes of patients with primary hypophysitis (PH).

METHODS

Patients with PH who were followed up between 2007 and 2018 at our clinic were evaluated. Clinical, endocrinologic, pathologic, radiologic findings and treatment modalities were assessed.

RESULTS

Seventeen patients with PH were assessed. The median follow-up was 24 (range, 6-84) months. Histologic confirmation was available in 8 patients (6 lymphocytic hypophysitis, 1 lymphocytic-granulomatous hypophysitis, 1 xanthomatous hypophysitis). None of the cases were diagnosed after pregnancy. Two patients had an autoimmune disease. The most commonly seen symptom was headache. The most common anterior pituitary deficiencies were hypocortisolemia and hypothyroidism. The radiologic findings of the patients at the time of diagnosis revealed various results including space-occupying lesion (41.2%), loss of posterior hypophysis bright spot (47.1%), pituitary stalk thickening (41.2%), uniform contrast enhancement (17.6%), partially empty sella (11.8%), optic chiasm compression (11.8%). The most frequent initial treatment modality was observation. Ten patients who were followed up conservatively had no endocrinologic deterioration; additional treatment was not needed in 8 of these 10 patients. The second most frequent initial treatment modality was pituitary surgery. Five patients received steroid treatment. We found serious adverse effects during steroid treatment in 3 of 5 (60%) patients; unilateral avascular necrosis of the femoral head (n=2), diabetes mellitus(n=1).

CONCLUSION

Correctly diagnosing PH and giving appropriate treatment is challenging. It is unclear whether active treatment with steroids improves clinical outcomes. The serious adverse effects of steroids are also taken into account. Observation, surgery and/or radiotherapy can be appropriate treatment modalities for selected patients.

Hypophysitis Outcome and Factors Predicting Responsiveness to Glucocorticoid Therapy: A Prospective and Double-Arm Study

CONTEXT

Primary autoimmune hypophysitis (PAH) evolves in most untreated cases in irreversible hypopituitarism. PAH outcome, instead, after immunosuppressive treatment has not been completely clarified.

OBJECTIVE

To evaluate hypophysitis and pituitary function outcomes.

DESIGN

A prospective, double-arm study with a 2-year follow-up.

SETTING

Referral center for pituitary disease.

PATIENTS

Twenty PAH cases.

INTERVENTIONS

Oral prednisone 50 mg/d or conservative strategy by observation.

MAIN OUTCOME MEASURES

Primary endpoint was the improvement/stabilization/worsening of PAH from baseline to a 2-year visit. Secondary endpoint was the improvement/stabilization/worsening of pituitary function from baseline to a 2-year visit.

RESULTS

Twelve patients (57.1%) were treated with a glucocorticoid-immunosuppressive therapy, and eight patients (42.9%) were observed. At the 2-year visit, PAH improvement/recovery occurred in eight immunosuppressive-treated (66.7%) patients and in two untreated patients (25%). PAH worsened in three untreated patients (37.5%) and was considered stable in four immunosuppressive-treated (33.3%) and three untreated patients (37.5%). Improvement/recovery of pituitary function occurred more frequently in immunosuppressive-treated patients (58.3%) compared with untreated ones (25%; P = 0.04). Responsiveness to immunosuppressive treatment is correlated with antipituitary antibody presence (P = 0.01), occurrence of diabetes insipidus at PAH diagnosis (P = 0.01), absence of the physiological neuropituitary "bright spot" on T1-weighed images (P = 0.01), and pituitary stalk at optical chiasm larger than 3.9 mm (area under the curve: 0.97, sensibility: 100%, specificity: 100%; P = 0.04). On the other hand, we failed to identify factors predicting the outcome, among untreated patients.

CONCLUSIONS

Glucocorticoid treatment of hypophysitis improves pituitary secretion and should be encouraged in accordance with the evaluation of endocrine-, immunological-, and morphological-predictive markers.