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.

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.

Mikulicz's disease combined with IgG4-related hypophysitis: a case report.

BACKGROUND: IgG4-related diseases are very uncommon, and its diagnosis and treatment are complicated as it encompasses multiple disciplines. CASE PRESENTATION: A 77-year-old woman was admitted with a jaw mass and nausea and vomiting. Laboratory tests showed elevated serum IgG4, pituitary MRI suggested thickening of the pituitary stalk, and head and neck CT suggested orbital and mandibular masses. Patients with mandibular mass were diagnosed with Mikulicz's disease with IgG4-related hypophysitis. We found no other evidence of causing thickening of the pituitary stalk. She was given oral prednisolone 30 mg daily, and her nausea and vomiting improved significantly, and the mandibular and ocular masses decreased in size. CONCLUSION: Mikulicz's disease combined with IgG4-related hypophysitis is a rare case of IgG4-RD in elderly women. IgG4-RD is one of the causes of head and neck exocrine gland mass and pituitary stalk thickening in the elderly.

Th17 Cells Contribute to the Pathology of Autoimmune Hypophysitis.

Autoimmune hypophysitis is classified as primary if its origin is idiopathic and secondary if it develops as a consequence of treatment with immune checkpoint inhibitors. Expanding use of immunotherapy has been paralleled by the increasing hypophysitis prevalence. However, understanding of the immune responses driving the disease remains limited. Using a mouse model of primary hypophysitis, we have identified CD4+ T lymphocytes to be the main pituitary-infiltrating immune cell population. Functional analysis showed that they display a Th17 and Th1/Th17 phenotype. To examine involvement of proinflammatory Th1, Th17, and Th1/17 subsets in hypophysitis, we have isolated RNA from the formalin-fixed paraffin-embedded pituitary specimens from 16 hypophysitis patients (three of whom had hypophysitis secondary to immune checkpoint inhibitors), 10 patients with adenoma, and 23 normal pituitaries obtained at autopsy. Transcript levels of IFN-γ, IL-17A, IL-4, IL-10, TGF-ß, CD4, CD8α, and class II MHC transactivator were analyzed by the reverse transcription-quantitative PCR (RT-qPCR). Pituitary glands of patients with hypophysitis showed significantly higher IL-17A, CD4, and class II MHC transactivator mRNA levels compared with adenoma and normal pituitaries. All three secondary hypophysitis patients showed detectable IL-17A levels, but other cytokines were not detected in their pituitaries. Levels of IFN-γ, IL-4, IL-10, and TGF-ß did not differ between the groups. TGF-ß transcript was found in significantly fewer hypophysitis pituitaries (2 out of 16) compared with adenoma (7 out of 10) and normal pituitaries (11 out of 23). Presence of TGF-ß in two hypophysitis patients was associated with significantly lower IL-17A mRNA levels compared with hypophysitis patients with no detectable TGF-ß (p = 0.03).

Concurrent IgG4-related hypophysitis and clinically nonfunctioning gonadotroph pituitary neuroendocrine tumor.

BACKGROUND: Some patients develop immunoglobulin G4 (IgG4)-related hypophysitis associated with systemic diseases. More than 30 cases of IgG4-related hypophysitis have been reported. However, biopsy has rarely been performed in these patients, and none have had an associated pituitary neuroendocrine tumor (PitNET). We present a case of concurrent IgG4-related hypophysitis and PitNET. CASE PRESENTATION: A 56-year-old Japanese man arrived at the hospital with visual impairment, bitemporal hemianopia, and right abducens nerve palsy. Magnetic resonance imaging revealed pituitary body and stalk swelling as well as a small poorly enhanced right anterior lobe mass. Laboratory and loading test results suggested hypopituitarism. Because IgG4 level was elevated, a systemic examination was performed; multiple nodules were found in both lung fields. The diagnosis was based on an endoscopic transnasal biopsy of the pituitary gland. A histopathological examination revealed a marked infiltration of plasma cells into the pituitary gland, which was strongly positive for IgG4. The histological features of the resected tumor were consistent with those of gonadotroph PitNET, which was immunohistochemically positive for follicle-stimulating hormone-ß and steroidogenic factor-1, and no plasma cell infiltration was observed. Based on the histopathological examination results, steroid therapy was initiated, which reduced pituitary gland size and serum IgG4 levels. DISCUSSION AND CONCLUSIONS: This is the first reported case of IgG4-related hypophysitis with PitNET. Although no pathological findings indicating a relationship between the two conditions were found, we were able to preoperatively differentiate multiple lesions via detailed diagnostic imaging.

Paraneoplastic autoimmune hypophysitis: a novel form of paraneoplastic endocrine syndrome.

Paraneoplastic syndromes are defined by symptoms or signs resulting from damage to organs or tissues that are remote from the site of malignant neoplasms or its metastasis. They are due to tumor secretion of functional hormones or peptides or are related to immune cross-reactivity with the host tissue. In particular, paraneoplastic endocrine syndromes are mainly caused by ectopic hormone production by the tumor such as PTHrP in humoral hypercalcemia in malignancy and ACTH in ectopic ACTH syndrome. Recently, it has been reported that a specific form of hypophysitis is caused as an immune-mediated paraneoplastic syndrome; paraneoplastic autoimmune hypophysitis, in which an ectopic pituitary antigen expression in the tumor evoked autoimmunity against pituitary-specific antigens, resulting in hypophysitis and exhibiting the injury of specific anterior pituitary cells by cytotoxic T cells. This novel clinical entity, paraneoplastic autoimmune hypophysitis consists of several conditions such as anti-PIT-1 hypophysitis and a part of isolated ACTH deficiency and immune checkpoint inhibitor-related hypophysitis with common mechanisms. These conditions can explain at least in part, the underlying mechanisms of acquired specific pituitary hormone deficiencies. In addition, it is important to apply a comprehensive discipline of onco-immuno-endocrinology to understand the pathophysiology and this approach; the expansion and application of immune-mediated paraneoplastic syndrome to endocrine diseases may give a new clue to understand pathophysiology of the autoimmunity against endocrine organs.

Two children with lymphocytic hypophysitis presenting with positive anti-rabphilin-3A antibody.

Lymphocytic hypophysitis (LYH) is a rare chronic inflammatory disease characterized by lymphocytic infiltration of the anterior or posterior pituitary gland and hypothalamus. LYH is subdivided into lymphocytic adenohypophysitis (LAH), lymphocytic infundibulo-neurohypophysitis (LINH), and lymphocytic panhypophysitis (LPH) depending on the primary site. Most cases occur in adults, with few cases reported in children, and it is especially important to distinguish LYH from suprasellar malignancies, such as germ cell tumors and other neoplastic diseases. Although a biopsy is necessary for definitive diagnosis, it is desirable to be able to diagnose the disease without biopsy if possible, especially in children, because of the surgical invasiveness of the procedure. Recently, serum anti-rabphilin-3A antibodies have attracted attention as diagnostic markers for LYH, especially in LINH, but there are only a few reports on pediatric patients. In the present study, we experienced two children with LPH and LAH, respectively, who tested positive for anti-rabphilin-3A antibodies. This is the first report of children with LYH other than LINH positive for anti-rabphilin-3A antibodies, and anti-rabphilin-3A antibodies may be a useful non-invasive diagnostic marker not only for LINH but also for LYH in general. We also discuss the sensitivity and specificity of anti-rabphilin-3A antibody testing in cases where histological diagnosis has been made.

Early Pulse Glucocorticoid Therapy and Improved Hormonal Outcomes in Primary Hypophysitis.

INTRODUCTION: The role of glucocorticoids in primary autoimmune hypophysitis (PAH) has been fraught with variability in regimens, leading to inconsistent outcomes in terms of anterior pituitary (AP) hormonal recovery. Hence, we aimed to compare the clinical, hormonal, and radiological outcomes of a standardized high-dose glucocorticoid therapy group (GTG) in PAH with a matched clinical observation group (COG). METHODS: Thirty-nine retrospective patients with PAH evaluated and treated at a single center in western India from 1999 to 2019 with a median follow-up duration of 48 months were subdivided into the GTG (n = 18) and COG (n = 21) and compared for the outcomes. RESULTS: Baseline demographic, hormonal, and radiological features matched between the groups, except pituitary height, which was significantly higher in GTG. Cortisol, thyroid, and gonadal axes were affected in 25 (64%), 22 (56%), and 21 (54%) patients, respectively, and central diabetes insipidus was seen in 7 (18%) patients. Panhypophysitis (PH) was the most common radiological subtype (n = 33, 84.6%). Resolution of mass effects was similar in both groups. Overall and complete AP hormonal recovery was significantly higher in the GTG than in the COG (12/14 [85.7%) vs. 6/14 [42.8%], p = 0.02; 10/14 [71.4%] vs. 1/14 [7.7%], p = 0.0007, respectively). Proportion of cases with empty sella were significantly higher in the COG (9/20 [45%] vs 1/17 [5.9%], p = 0.001). Among PH patients in the GTG (n = 17), we found duration from symptoms onset to treatment as the predictor of recovery. CONCLUSION: In a PH subtype-predominant PAH cohort, a standardized high-dose glucocorticoid regimen resulted in higher overall and complete AP hormonal recovery than that in the COG. Initiation of glucocorticoids in the early disease course may have been contributory.

Secondary autoimmune hypothalamitis with severe memory impairment 7 years after the onset of diabetes insipidus due to lymphocytic hypophysitis: a case report.

BACKGROUND: Autoimmune hypothalamitis is a very rare neuroendocrine disorder that causes central diabetes insipidus, headache, visual impairment, and sometimes cognitive impairment. Autoimmune hypothalamitis may occur in association with autoimmune hypophysitis, including lymphocytic hypophysitis, or in isolation. It is not known whether autoimmune hypothalamitis and autoimmune hypophysitis are consecutive diseases. CASE PRESENTATION: A 52-year-old woman developed autoimmune hypothalamitis 7 years after developing central diabetes insipidus due to lymphocytic hypophysitis, resulting in severe memory impairment. High-dose intravenous methylprednisolone therapy improved her cognitive function and decreased the size of the lesion. CONCLUSION: This case presented a unique clinical course, with a long period of time between the onset of autoimmune hypopituitaritis and the development of autoimmune hypothalamitis.

Sellar germinoma mimicking IgG4-related hypophysitis: a case report.

BACKGROUND: The differential diagnosis of IgG4-related hypophysitis and other inflammatory diseases or tumors involving sellar region is challenging even after sellar biopsy. Sellar germinoma is usually infiltrated by lymphocytes or plasma cells, and may be confused with hypophysitis. CASE PRESENTATION: A 36-year-old man with diabetes insipidus, elevated serum IgG4 level (336 mg/dl), and sellar mass was suspected to have IgG4-related hypophysitis, and no other lesion of IgG4-related disease was detected. After treated by prednisone and mycophenolate mofetil, the serum IgG4 decreased to 214 mg/dl. However, after withdrawal of the drugs, the IgG4 level increased to 308 mg/dl. Endocrine assessments revealed panhypopituitarism, and the sellar mass enlarged. Transsphenoidal sellar exploration and biopsy was conducted. Pathological examination showed that the lesion was germinoma with lymphocytes and plasma cells infiltration, and IgG4-staining was positive (70/HPF, IgG4/IgG ratio = 10%). The patient was then treated by cisplatin and etoposide. After four cycles of chemotherapy, the serum IgG4 was 201 mg/dl, and the sellar mass was invisible. CONCLUSION: Sellar germinoma can mimic the clinical characteristics of IgG4-related hypophysitis. Poor response to glucocorticoids can be used as an exclusion criterion in the clinical diagnosis of IgG4-related hypophysitis.

Lymphocytic panhypophysitis and anti-rabphilin-3A antibody with pulmonary sarcoidosis.

PURPOSE: To explore the clinical significance of anti-rabphillin-3A antibody for the differential diagnosis of lymphocytic panhypophysitis. METHODS AND RESULTS: A 58-year-old Japanese man developed uveitis of unknown cause in 2017. In 2019, he became aware of polyuria. In August 2020, he noticed transient diplopia and was diagnosed with right abducens nerve palsy. At the same time, he complained of fatigue and loss of appetite. Head magnetic resonance imaging demonstrated enlargement of the pituitary stalk and pituitary gland, corresponding to hypophysitis. Hormone stimulation tests showed blunted responses with respect to all anterior pituitary hormones. Central diabetes insipidus was diagnosed on the basis of a hypertonic saline loading test. Taking these findings together, a diagnosis of panhypopituitarism was made. Computed tomography showed enlargement of hilar lymph nodes. Biopsies of the hilar lymph nodes revealed non-caseating epithelioid cell granulomas that were consistent with sarcoidosis. Biopsy of the anterior pituitary revealed mild lymphocyte infiltration in the absence of IgG4-positive cells, non-caseating granulomas, or neoplasia. Western blotting revealed the presence of anti-rabphilin-3A antibody, supporting a diagnosis of lymphocytic panhypophysitis. Because the patient had no visual impairment or severe uveitis, we continued physiological hormone replacement therapy and topical steroid therapy for the uveitis. CONCLUSION: To the best of our knowledge, this is the first case of anti-rabphilin 3A antibody positive lymphocytic panhypophysitis comorbid with sarcoidosis, diagnosed by both pituitary and hilar lymph node biopsy. The utility of anti-rabphilin-3A antibody for the differential diagnosis of hypophysitis like this case should be clarified with further case studies.

Hypophysitis.

OBJECTIVE: Hypophysitis is considered a rare inflammatory disease of the pituitary gland. For a long time, primary autoimmune hypophysitis has stood out as the most relevant type of hypophysitis. However, with the advent of immunotherapy for the treatment of malignancies and identification of hypophysitis as an immune-related adverse event, hypophysitis has garnered increasing interest and recognition. Therefore, awareness, early recognition, and appropriate management are becoming important as the indication for immunomodulatory therapies broaden. METHODS: In this review, we discuss the epidemiology, diagnosis, and treatment of hypophysitis with a focus on recent data and highlight subtypes of particular interest while recognizing the gaps in knowledge that remain. RESULTS: Regardless of cause, symptoms and signs of hypophysitis may be related to mass effect (headache and visual disturbance) and hormonal disruption that warrant prompt evaluation. In the vast majority of cases, a diagnosis of hypophysitis can be made presumptively in the appropriate clinical context with radiologic findings consistent with hypophysitis and after the exclusion of other causes. CONCLUSION: Although subtle differences currently exist in management and outcome expectations between primary and secondary causes of hypophysitis, universally, treatment is aimed at symptom management and hormonal replacement therapy.

Autoimmune antibodies correlate with immune checkpoint therapy-induced toxicities.

Immune checkpoint (IC) therapy provides substantial benefits to cancer patients but can also cause distinctive toxicities termed immune-related adverse events (irAEs). Biomarkers to predict toxicities will be necessary to improve management of patients receiving IC therapy. We relied on serological analysis of recombinant cDNA expression libraries to evaluate plasma samples from patients treated with IC therapy and identified autoantibodies, both in pretreatment and on-treatment samples prior to the development of irAEs, which correlate with the development of immune-related hypophysitis (anti-GNAL and anti-ITM2B autoantibodies) and pneumonitis (anti-CD74 autoantibody). We developed an enzyme-linked immunosorbent assay and tested additional patient samples to confirm our initial findings. Collectively, our data suggest that autoantibodies may correlate with irAEs related to IC therapy, and specific autoantibodies may be detected early for the management of irAEs.

IgG4-related hypophysitis: a retrospective cohort study.

PURPOSE: IgG4-related hypophysitis (IgG4-RH) is a rare chronic inflammatory condition of the pituitary gland. This study reports the presentation, management and outcomes for patients with histologically proven IgG4-related hypophysitis. METHODS: A prospectively maintained electronic database was searched over a 14-year period from 1 January 2007 to 31 December 2020 at a single academic centre to identify all patients with a histological diagnosis of IgG4-RH. A retrospective case note review from electronic health records was conducted for each case to extract data on their presentation, management and outcomes. RESULTS: A total of 8 patients (5 male) with a median age of 51 years were identified. The most common presenting symptoms were headache (4/8; 50%), fatigue (3/8; 37.5%) and visual impairment (2/8; 25%). Three patients were initially treated with high-dose steroids aiming for reduction of the pituitary mass. However, ultimately all patients underwent transsphenoidal surgery. Post-operative changes included radiological reduction in pituitary mass in all patients that had imaging (7/7; 100%), improvement in vision (1/2; 50%), residual thick pituitary stalk (5/7; 71.4%), persistent anterior hypopituitarism (4/8; 50%) and panhypopopituitarism including diabetes insipidus (3/8; 37.5%). CONCLUSIONS: IgG4-RH is an increasingly recognised entity presenting with a variety of symptoms and signs. Clinical presentation is similar to other forms of hypophysitis. It is therefore important to consider IgG4-RH as a differential and to have a low threshold for pituitary biopsy, the diagnostic gold standard. The diagnosis of IgG4-RH will guide decisions for additional workup for IgG4-related disease, multi-disciplinary team involvement and follow-up.

Inhibition of IRAK1 Is an Effective Therapy for Autoimmune Hypophysitis in Mice.

Autoimmune hypophysitis (AH) is an autoimmune disease of the pituitary for which the pathogenesis is incompletely known. AH is often treated with corticosteroids; however, steroids may lead to considerable side effects. Using a mouse model of AH (experimental autoimmune hypophysitis, EAH), we show that interleukin-1 receptor-associated kinase 1 (IRAK1) is upregulated in the pituitaries of mice that developed EAH. We identified rosoxacin as a specific inhibitor for IRAK1 and found it could treat EAH. Rosoxacin treatment at an early stage (day 0-13) slightly reduced disease severity, whereas treatment at a later stage (day 14-27) significantly suppressed EAH. Further investigation indicated rosoxacin reduced production of autoantigen-specific antibodies. Rosoxacin downregulated production of cytokines and chemokines that may dampen T cell differentiation or recruitment to the pituitary. Finally, rosoxacin downregulated class II major histocompatibility complex expression on antigen-presenting cells that may lead to impaired activation of autoantigen-specific T cells. These data suggest that IRAK1 may play a pathogenic role in AH and that rosoxacin may be an effective drug for AH and other inflammatory diseases involving IRAK1 dysregulation.

An autopsy case study of lymphocytic hypophysitis induced by nivolumab treatment for esophageal malignant melanoma.

Immune checkpoint inhibitors such as anti-cytotoxic T-lymphocyte antigen-4 and anti-programmed death-1 antibodies are effective against malignant tumors. However, they induce unique adverse events known as immune-related adverse events. Hypophysitis is one of the most frequent immune-related adverse events of anti-cytotoxic T-lymphocyte antigen-4 therapies. However, there have been few reports describing the pathological findings of hypophysitis induced by anti-programmed death-1 antibodies. The present case is the first autopsy case of hypophysitis induced by nivolumab monotherapy, an anti-programmed death-1 antibody. Pathologically, lymphocytes infiltrated the anterior lobe of the pituitary gland, and the number of pituitary cells, especially adrenocorticotropic hormone-positive cells, decreased. However, necrosis and remarkable fibrosis were not observed. Immunohistologically, some pituitary cells expressed programmed death-ligand 1. Lymphocytes were predominantly CD8-positive T cells, and CD68-positive macrophages and CD20-positive B-cells were also observed. IgG and C4d were deposited on pituitary cells, but IgG4 (a subclass of nivolumab) was not detected. These findings indicate that type IVc and type II hypersensitivity mechanisms may occur in hypophysitis induced by anti-programmed death-1 antibodies and that the inflammatory mechanisms underlying hypophysitis induced by anti-programmed death-1 and anti-cytotoxic T-lymphocyte antigen-4 antibodies are different.

A case of isolated hypothalamitis with a literature review and a comparison with autoimmune hypophysitis.

Idiopathic hypothalamitis is a rare condition that can cause anterior pituitary dysfunction and central diabetes insipidus (CDI), occasionally accompanied by a disturbance of autonomic regulation known as hypothalamic syndrome. This condition has been described as a subtype of autoimmune (lymphocytic) hypophysitis; however, some cases of isolated hypothalamic involvement with no inflammatory lesions in either the pituitary gland or infundibulum have been reported. The detailed epidemiology and pathophysiology of isolated hypothalamitis have not been clarified. We herein report a case of a solitary hypothalamic lesion in a young woman who showed spontaneous development of CDI and panhypopituitarism accompanied by hyperphagia. The hypothalamic lesion increased from 11 × 7 to 17 × 7 mm over 16 months based on the sagittal slices of magnetic resonance imaging examinations. The negative results for anti-pituitary antibodies and anti-Rabphilin-3A antibodies suggested that upward extension of lymphocytic adenohypophysitis or infundibulo-neurohypophysitis was unlikely. Infectious disease, granulomatosis, Langerhans cell histiocytosis, vasculitis, and systemic neoplastic diseases were excluded by the findings of a laboratory investigation, cerebrospinal fluid examination, and imaging studies. To make a definitive diagnosis, we performed a ventriculoscopic biopsy of the hypothalamic lesion. Histology revealed an infiltration of nonspecific lymphoplasmacytes with no evidence of neoplasm, which was consistent with a diagnosis of idiopathic hypothalamitis. Subsequently, the patient was treated with methylprednisolone pulse therapy followed by oral prednisolone. The hypothalamic lesion improved and remained undetectable after withdrawal of the prednisolone, suggesting that the glucocorticoid treatment was effective for isolated hypothalamitis while the patient remains dependent on the replacement of multiple hormones.

Postpartum headache: A broader differential.

A 40-year-old female presented to the ED with a history of intermittent headaches since a vaginal delivery 8 days prior. Her pregnancy was unremarkable and was not complicated by pre-eclampsia. She did not present with signs or symptoms consistent with postdural puncture headache or pre-eclampsia. Her delivery was not complicated by hypotension or post-partum hemorrhage. By chance, she was found to be hyponatremic and admitted to internal medicine for further work-up. She was diagnosed with postpartum lymphocytic adenohypophysitis and treated with steroids. She was discharged with a steroid taper and had complete resolution on follow up. Lymphocytic hypophysitis (LH), or commonly known as autoimmune hypophysitis, is a rare inflammatory condition affecting the pituitary gland. Acute LH can result in sudden death as demonstrated in some case reports. The most common symptom in >50% of cases is headache. First-line pharmacological treatment consists of high-dose corticosteroids and is effective in reducing pituitary size and improving endocrine insufficiency in 75% of cases. LH is a potential cause of postpartum headache that can be easily screened for with history and routine bloodwork and has good outcomes with early intervention. LH should be added to the differential for postpartum headaches presenting to the emergency department and routine blood work should be considered for all postpartum headaches.

Role of 18F-fluorodeoxyglucose (FDG) and 18F-2-fluorodeoxy sorbitol (FDS) in autoimmune hypophysitis: a case report.

BACKGROUND: Autoimmune hypophysitis is a rare disease characterized by the infiltration of lymphocytic cells into the pituitary gland. 18F-fluorodeoxyglucose (FDG) and 18F-2-fluorodeoxy sorbitol (FDS) positron emission tomography (PET) are well-established and emerging techniques, respectively, which may aid in the diagnosis and classification of autoimmune hypophysitis. CASE PRESENTATION: Here, we report a 40-year-old female diagnosed with central diabetes insipidus and multiple pituitary hormone deficiencies, and MRI revealed homogeneous signals in the pituitary gland as well as thickened in the pituitary stalk. FDG PET localized the pituitary and pituitary stalk lesions and displayed an SUVmax of 5.5. FDS, a sensitive radiotracer for bacterial infections but remains unproven under aseptic inflammation, also demonstrated elevated radioactivity, with an SUVmax of 1.1 at 30 min and 0.73 at 120 min. Transnasal biopsy suggested a diagnosis of autoimmune hypophysitis, and the patient displayed radiological and clinical improvement after treatment with glucocorticoids and hormone replacement. CONCLUSIONS: Autoimmune hypophysitis can display elevated FDG uptake, which aids in the localization of the lesions. In addition to revealing bacterial infection specifically, FDS can also accumulate under autoimmune conditions, suggesting that it could serve as a potential radiotracer for both bacterial and aseptic inflammation. TRIAL REGISTRATION: The patient was enrolled in study NCT02450942 (clinicaltrials.gov, Registered May 21, 2015).

Anti-pituitary antibodies as a marker of autoimmunity in pituitary glands.

Autoimmunity contributes to the pathogenesis of hypophysitis, a chronic inflammatory disease in the pituitary gland. Although primary hypophysitis is rare, the number of pituitary dysfunction cases induced by immune checkpoint inhibitors (ICIs) is increasing. While it is difficult to prove the involvement of autoimmunity in the pituitary glands, circulating anti-pituitary antibodies (APAs) can be measured by indirect immunofluorescence and used as a surrogate marker of pituitary autoimmunity. APAs are present in several pituitary diseases, including lymphocytic adenohypophysitis, lymphocytic infundibulo-neurohypophysitis (LINH), IgG4-related hypophysitis, and pituitary dysfunction induced by ICIs. Mass spectrometry analysis of antigens targeted by APAs clarified rabphilin-3A as an autoantigen in LINH. This demonstrates that APAs can be applied as a probe to identify novel autoantigens in other pituitary autoimmune diseases, including pituitary dysfunction induced by ICIs, which can aid in biomarker discovery.