Introduction: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an uncommon inflammatory demyelinating disorder of the central nervous system, with a reported prevalence of 1.3–2.5 per 100,000. Hypothalamic–pituitary involvement is rare and can mimic structural lesions, presenting with varying degrees of hypopituitarism and central diabetes insipidus. Case: A 30-year-old male presented with a 2-year history of poor concentration, blurring of vision and lethargy. Initial investigations revealed severe hypernatremia (serum sodium 165 mmol/L) and a 1.4 × 2.1 × 1.3 cm suprasellar cistern mass on CT scan, with differential diagnoses including meningioma and germinoma. Brain magnetic resonance imaging showed abnormal signals in the optic pathways and hypothalamus, raising suspicion of a demyelinating process. Endocrine evaluation confirmed panhypopituitarism: elevated prolactin (1125.2 mIU/L), hypogonadotropic hypogonadism (follicle-stimulating hormone 0.7 IU/L, LH 0.3 IU/L, testosterone <0.35 nmol/L), central hypothyroidism (TSH 3.8 mIU/L, free T4 5.88 pmol/L) and low cortisol (33.1 nmol/L). Persistent hypernatremia (up to 171 mmol/L) with high serum osmolality (370 mOsm/kg) and low urine osmolality (237 mOsm/kg) confirmed central diabetes insipidus, as urine osmolality rose to 755 mOsm/kg following intravenous desmopressin. He was commenced on sublingual desmopressin 60 micrograms twice daily, hydrocortisone (10 mg morning, 5 mg afternoon), levothyroxine 75 micrograms daily and monthly intramuscular testosterone 150 mg. Subsequent readmissions for generalized weakness and fever led to cerebrospinal fluid analysis and serum testing, which were positive for MOG antibodies and negative for aquaporin-4 antibodies, confirmed MOGAD. During a third admission with recurrent generalized weakness, he responded favorably to intravenous methylprednisolone (1 g daily for 5 days), followed by a tapering oral prednisolone regimen. Conclusion MOGAD can involve the hypothalamic–pituitary axis and mimic a suprasellar mass. In patients with panhypopituitarism, central diabetes insipidus and compatible imaging, inflammatory demyelination should be suspected. MOG antibody positivity and response to corticosteroids support diagnosis and guide management.
Diabetes Insipidus ; Hypopituitarism

Introduction: Immunoglobulin G4-related hypophysitis (IgG4-RH) is a rare fibro-inflammatory disorder affecting the pituitary gland. Glucocorticoids remain the first-line therapy, but their use may be complicated in patients with significant metabolic comorbidities. We report a case of suspected IgG4-RH presenting with hyperosmolar hyperglycemic state (HHS), highlighting the challenges of balancing disease control against glucocorticoid metabolic toxicity adverse effects. Case: A 32-year-old female with obesity and newly diagnosed diabetes mellitus was admitted with HHS. Prior to admission, she reported weight fluctuations, episodic headaches, progressive visual disturbance, and secondary amenorrhea. Following resolution of HHS, persistent polyuria of 10–16 L/day prompted further evaluation and led to a diagnosis of arginine vasopressin deficiency. Anterior pituitary hormonal work-up revealed hypogonadotropic hypogonadism. Pituitary magnetic resonance imaging demonstrated infundibular thickening measuring 0.5 cm, with concomitant marked bilateral parotid enlargement. Serum IgG4 was elevated at 2.26 g/L (0.63–2.01), raising strong suspicion for IgG4-RH with systemic involvement. Histopathological confirmation from the parotid gland biopsy was consistent with sialadenosis. She was commenced on sublingual desmopressin and cyclical sex hormone replacement therapy. Given the provisional diagnosis of IgG4-RH, oral prednisolone 40 mg daily was initiated as a reduced induction regimen. However, treatment was poorly tolerated, with rapid weight gain from 93 to 100 kg and worsening glycemic control. Prednisolone was therefore tapered rapidly to 10 mg daily. Repeat imaging demonstrated interval improvement in infundibular thickening, but no functional endocrine recovery was observed. Conclusion This case illustrates the therapeutic challenge of managing IgG4-RH in the setting of pre-existing metabolic syndrome. Although glucocorticoids are effective for induction, their metabolic adverse effects may significantly restrict treatment tolerability. Early consideration of steroidsparing agents, such as rituximab or azathioprine, may be important to achieve remission while minimizing glucocorticoid-related adverse effects.
Autoimmune Hypophysitis

Introduction: Pituitary macroadenomas may present with mass effects, hypopituitarism, or hormone hypersecretion. Hyperprolactinemia, resulting from a prolactin-secreting tumor or stalk compression, typically suppresses gonadotropins. Thus, elevated follicle-stimulating hormone (FSH) and luteinizing hormone (LH) with low testosterone in this context are unusual. We report a macroprolactinoma with a clinically non-functioning gonadotroph adenoma. Case: A 69-year-old male presented with acute giddiness and headache while in Vietnam. He reported reduced libido but no visual symptoms or galactorrhea. Examination showed no neurological deficits, normal visual fields, and secondary sexual characteristics; bilateral testes volume of 25 mL. Magnetic resonance imaging (MRI) brain revealed a 1.6 × 2.2 × 2.1 cm pituitary macroadenoma compressing the optic chiasm and pituitary stalk. Initial pituitary evaluation demonstrated hyperprolactinemia (prolactin >200 µg/L; normal 2.4–13.1), central hypothyroidism (T4 6.8 pmol/L [7.8–14.4], thyroid-stimulating hormone 2.3 mIU/L [0.38–5.3]), elevated FSH (21.5 IU/L [1.2–19.2]) and LH (191 IU/L [1.24–8.62]), low testosterone (8.88 nmol/L), normal insulin-like growth factor 1 (IGF-1) (68 µg/L [46.5–191.9]), and cortisol 237 nmol/L. Cabergoline was initiated at 0.25 mg twice weekly and titrated to 1 mg twice weekly over 4 months, alongside levothyroxine 25 µg daily. Repeated MRI brain 2 months after cabergoline initiation showed a persistent macroadenoma (1.7 × 2.2 × 2.2 cm) with bilateral cavernous sinus extension. Prolactin decreased to <170 µg/L, central hypothyroidism persisted; levothyroxine was optimized, and hydrocortisone was initiated. At the 5-month follow-up, prolactin further improved to 57 µg/L. Central hypothyroidism and borderline adrenal function persisted, requiring continued replacement therapy. Testosterone remained low-normal (10.2 nmol/L) despite elevated FSH (15.4 IU/L) and LH (92 IU/L). Followup MRI and hormonal reassessment were planned in May 2026. Conclusion Profoundly elevated prolactin level >200 µg/L and response to cabergoline reflect true prolactinoma rather than stalk effect. Persistently low testosterone with discordant high FSH/LH suggests a non-functioning gonadotroph component producing biologically inactive gonadotropins. Definitive diagnosis requires histopathological confirmation, while serial biochemical and radiological follow-up guides management and clarifies tumor subtype.
Gonadotrophs ; Hyperprolactinemia

Introduction: Hypernatremia is a common yet high-mortality electrolyte disorder. The hypothalamus maintains water homeostasis via thirst sensation and arginine vasopressin (AVP) secretion. Hypothalamic tumors, such as gliomas, can progressively destroy these osmoregulatory centres, leading to “malignant” hypernatremia (>180 mmol/L). We report a case of life-threatening hypernatremia in a patient with a progressive hypothalamic glioma, exploring its complex pathophysiology. Case: A 41-year-old female with a progressive high-grade hypothalamic glioma and persistent hydrocephalus presented with generalized weakness, reduced oral intake, and dehydration. Her initial Glasgow Coma Scale was E4V3M6. Laboratory investigations revealed malignant hypernatremia (serum sodium 209 mmol/L) and a serum osmolarity of 441 mOsm/kg. Despite life-threatening dehydration (urea 26.2 mmol/L, creatinine 343 umol/L), she was still able to deceptively produce urine output of 400 mL/day with a concentrated urine osmolarity of 890 mOsm/kg. A 1 mcg IV desmopressin trial reduced urine output to 60 mL/day and serum sodium by 10 mmol/L within 14 hours, confirming relative AVP deficiency. The patient’s malignant hypernatremia was gradually corrected to 168 mmol/L over 1 week (8–12 mmol/L/day) using controlled intravenous hydration. However, her condition deteriorated due to hospital-acquired infection, and she succumbed 10 days after admission. Conclusion This case underscores several critical learning points for managing hypothalamic emergencies. First, hypothalamic tumors can reset the osmostat or destroy osmoregulatory centres, causing adipsic AVP deficiency. Second, clinicians must be alert to “masked polyuria” where severe hypovolemia reduces the glomerular filtration rate, causing urine output to appear “normal” despite underlying AVP deficiency. This state of “relative polyuria” is a hallmark of hypothalamic hypernatremia, thus indicating that a normal urine output does not rule out AVP deficiency. While desmopressin is indicated, its use in adipsic patients demands strict fluid titration to prevent iatrogenic hyponatremia. Rapid hypotonic correction carries a proven risk of cerebral oedema, and sodium measurement accuracy varies significantly across laboratory methods in extreme ranges.
Hypernatremia ; Hypothalamic Neoplasms

Introduction: Polycystic ovary syndrome (PCOS) is the most common cause of hyperandrogenism in women of reproductive age. However, several endocrine disorders, particularly Cushing disease (CD), can closely mimic the clinical, biochemical, and radiological features of PCOS. This overlap may lead to misdiagnosis and delayed recognition of hypercortisolism, with significant metabolic and reproductive consequences. Case: We report a 24-year-old female with young-onset diabetes mellitus who was referred for endocrine co-management during admission for recurrent mons pubis and labial abscesses with poorly controlled glycemia. She had a 5-year history of progressive hirsutism, oligomenorrhoea, scalp hair loss, significant weight gain, and insulin resistance, and had previously been labelled as having PCOS during adolescence, with subsequent default of follow-up. On examination, she was obese (body mass index 33 kg/ m²) with plethoric facies, acanthosis nigricans, proximal myopathy, and hirsutism (Ferriman–Gallwey score 10), without overt virilization or acromegalic features. Biochemical evaluation demonstrated severe hyperandrogenism with markedly elevated total testosterone (7.05 nmol/L), suppressed gonadotropins, and adrenocorticotropic hormone (ACTH)-dependent hypercortisolism. Cortisol failed to suppress on low-dose dexamethasone testing, and 24-hour urinary free cortisol was markedly elevated (>4,900 nmol/24 h). Pelvic ultrasonography and computed tomography imaging showed polycystic ovarian morphology without evidence of an ovarian mass. Pituitary magnetic resonance imaging revealed a small right-sided pituitary microadenoma measuring 2.6 × 3.7 mm. Inferior petrosal sinus sampling demonstrated a central-to-peripheral ACTH gradient with adequate prolactin ratios, confirming pituitary CD. Conclusion This case highlights how Cushing disease can closely mimic PCOS, including polycystic ovarian morphology and hyperandrogenism. Progressive symptoms, severe biochemical androgen excess, and marked insulin resistance should prompt evaluation for secondary causes of hyperandrogenism, particularly hypercortisolism, to avoid delayed diagnosis and prolonged morbidity.
Female ; Hyperandrogenism ; Pituitary ACTH Hypersecretion ; Polycystic Ovary Syndrome

Managing a patient with both pituitary hypersecretory and hyposecretory manifestations may be perplexing. We report a 14-year-old female who presented with weight gain, polyuria and polydipsia. Biochemical results were consistent with Cushing disease with central diabetes insipidus. Pituitary magnetic resonance imaging showed right adenoma with stalk thickening. The immunohistochemistry staining of both adenomas was positive for adrenocorticotropic hormone, thyroid stimulating hormone, growth hormone and luteinizing hormone. Postoperatively, the patient developed panhypopituitarism with persistent diabetes insipidus. The coexistence of double adenomas can pose diagnostic and management challenges and is a common cause of surgical failure. Intraoperative evaluation is important in the identification of double or multiple pituitary adenomas in a patient presenting with multiple secretory manifestations.
Pituitary ACTH Hypersecretion ; Cushing disease ; Diabetes Insipidus

A 20-year-old male was referred to the Endocrinology Clinic in view of abnormal thyroid function test result and poor development of secondary sexual characteristics. He was born out of non-consanguineous marriage and had a history of breech delivery at term. He had perinatal complications in the form of delayed cry and lower respiratory tract infection. Developmental delay was also present (delayed motor, speech and social milestones). His scholastic performance was below average and he reported being the shortest child in class from kindergarten.
Hypopituitarism

Antineoplastic Agents/therapeutic use* ; Bortezomib/therapeutic use* ; Humans ; Inappropriate ADH Syndrome/chemically induced* ; Multiple Myeloma/drug therapy*

This paper discussed the guiding significance of "disease-syndrome-symptom" mode in FU Qing-zhu's Obstetrics and Gynecology(FU Qing-zhu Nyu Ke) for dealing with ovulation disorder infertility caused by hyperprolactinemia(HPRL). FU Qing-zhu's Obstetrics and Gynecology(FU Qing-zhu Nyu Ke) concentrates on the disease entities, main symptoms, pathogenesis, and syndrome differentiation, based on which the prescriptions are prescribed. This reflects the "disease-syndrome-symptom" mode, with the core lying in the "combination of disease with syndrome". The contained Discussion on Menstruation Regulation(Tiao Jing Pian) and Discussion on Getting Pregnant(Zhong Zi Pian) have important reference significance for later doctors in the diagnosis and treatment of inferti-lity, and many prescriptions are still in use due to good effects. It is believed in traditional Chinese medicine(TCM) that HPRL results from kidney deficiency and liver depression, among which kidney deficiency is the main cause. Liver depression accelerates the onset of HPRL, so the kidney-tonifying and liver-soothing herbs were mainly selected. The "disease-syndrome-symptom" mode in FU Qing-zhu's Obstetrics and Gynecology(FU Qing-zhu Nyu Ke) sheds enlightenment on the diagnosis and treatment of ovulation infertility caused by HPRL, in that it is not confined to disease entity and syndrome type. The integration of "disease-syndrome-symptom" highlights the main complaint of patients and emphasizes the main pathogenesis, thus giving full play to the overall advantage of syndrome differentiation. For multiple diseases in FU Qing-zhu's Obstetrics and Gynecology(FU Qing-zhu Nyu Ke) such as infertility due to liver depression, infertility due to obesity, delayed menstruation, and irregular menstruation, although the typical lactation symptom of HPRL is not mentioned, the medication can still be determined according to the chief complaint, syndrome type, and symptoms and signs, making up for the defects of excessive reliance on serum biochemical indicators in modern Chinese medicine. We should learn its diagnosis and treatment thoughts of paying attention to liver, spleen, kidney, and heart, holism, and strengthening body resistance to eliminate pathogenic factors.
Female ; Gynecology ; Humans ; Hyperprolactinemia/drug therapy* ; Infertility ; Obstetrics ; Ovulation ; Pregnancy

Pituitary immune-related adverse events induced by programmed cell death protein 1 inhibitors in advanced lung cancer patients: A report of 3 cases SUMMARY Programmed cell death protein 1 (PD-1) and its ligand 1 (PD-L1) have been widely used in lung cancer treatment, but their immune-related adverse events (irAEs) require intensive attention. Pituitary irAEs, including hypophysitis and hypopituitarism, are commonly induced by cytotoxic T lymphocyte antigen 4 inhibitors, but rarely by PD-1/PD-L1 inhibitors. Isolated adrenocorticotropic hormone(ACTH) deficiency (IAD) is a special subtype of pituitary irAEs, without any other pituitary hormone dysfunction, and with no enlargement of pituitary gland, either. Here, we described three patients with advanced lung cancer who developed IAD and other irAEs, after PD-1 inhibitor treatment. Case 1 was a 68-year-old male diagnosed with metastatic lung adenocarcinoma with high expression of PD-L1. He was treated with pembrolizumab monotherapy, and developed immune-related hepatitis, which was cured by high-dose methylprednisolone [0.5-1.0 mg/(kg·d)]. Eleven months later, the patient was diagnosed with primary gastric adenocarcinoma, and was treated with apatinib, in addition to pembrolizumab. After 17 doses of pembrolizumab, he developed severe nausea and asthenia, when methylprednisolone had been stopped for 10 months. His blood tests showed severe hyponatremia (121 mmol/L, reference 137-147 mmol/L, the same below), low levels of 8:00 a.m. cortisol (< 1 μg/dL, reference 5-25 μg/dL, the same below) and ACTH (2.2 ng/L, reference 7.2-63.3 ng/L, the same below), and normal thyroid function, sex hormone and prolactin. Meanwhile, both his lung cancer and gastric cancer remained under good control. Case 2 was a 66-year-old male with metastatic lung adenocarcinoma, who was treated with a new PD-1 inhibitor, HX008, combined with chemotherapy (clinical trial number: CTR20202387). After 5 months of treatment (7 doses in total), his cancer exhibited partial response, but his nausea and vomiting suddenly exacerbated, with mild dyspnea and weakness in his lower limbs. His blood tests showed mild hyponatremia (135 mmol/L), low levels of 8:00 a.m. cortisol (4.3 μg/dL) and ACTH (1.5 ng/L), and normal thyroid function. His thoracic computed tomography revealed moderate immune-related pneumonitis simultaneously. Case 3 was a 63-year-old male with locally advanced squamous cell carcinoma. He was treated with first-line sintilimab combined with chemotherapy, which resulted in partial response, with mild immune-related rash. His cancer progressed after 5 cycles of treatment, and sintilimab was discontinued. Six months later, he developed asymptomatic hypoadrenocorticism, with low level of cortisol (1.5 μg/dL) at 8:00 a.m. and unresponsive ACTH (8.0 ng/L). After being rechallenged with another PD-1 inhibitor, teslelizumab, combined with chemotherapy, he had pulmonary infection, persistent low-grade fever, moderate asthenia, and severe hyponatremia (116 mmol/L). Meanwhile, his blood levels of 8:00 a.m. cortisol and ACTH were 3.1 μg/dL and 7.2 ng/L, respectively, with normal thyroid function, sex hormone and prolactin. All of the three patients had no headache or visual disturbance. Their pituitary magnetic resonance image showed no pituitary enlargement or stalk thickening, and no dynamic changes. They were all on hormone replacement therapy (HRT) with prednisone (2.5-5.0 mg/d), and resumed the PD-1 inhibitor treatment when symptoms relieved. In particular, Case 2 started with high-dose prednisone [1 mg/(kg·d)] because of simultaneous immune-related pneumonitis, and then tapered it to the HRT dose. His cortisol and ACTH levels returned to and stayed normal. However, the other two patients' hypopituitarism did not recover. In summary, these cases demonstrated that the pituitary irAEs induced by PD-1 inhibitors could present as IAD, with a large time span of onset, non-specific clinical presentation, and different recovery patterns. Clinicians should monitor patients' pituitary hormone regularly, during and at least 6 months after PD-1 inhibitor treatment, especially in patients with good oncological response to the treatment.
Adenocarcinoma of Lung/drug therapy* ; Adrenocorticotropic Hormone/therapeutic use* ; Aged ; B7-H1 Antigen/therapeutic use* ; Humans ; Hydrocortisone/therapeutic use* ; Hyponatremia/drug therapy* ; Hypopituitarism/drug therapy* ; Immune Checkpoint Inhibitors ; Lung Neoplasms/pathology* ; Male ; Methylprednisolone/therapeutic use* ; Middle Aged ; Nausea/drug therapy* ; Pituitary Gland/pathology* ; Pneumonia ; Prednisone/therapeutic use* ; Programmed Cell Death 1 Receptor/therapeutic use* ; Prolactin/therapeutic use*