Granulomatosis with polyangiitis (GPA) is a systemic necrotizing vasculitis associated with anti-neutrophil cytoplasmic antibodies (ANCA). Although pituitary involvement is rare, it represents a clinically relevant manifestation that may present as a sellar mass mimicking a pituitary neuroendocrine tumour (PitNET), leading to diagnostic delay and inappropriate management. We report the case of a male patient who initially presented at 24 years of age with recurrent epistaxis and nasal crusting, with histopathological evidence of chronic granulomatous inflammation of undetermined aetiology. Four years later, he developed headache, diplopia, bitemporal hemianopia, polyuria, and polydipsia. Magnetic resonance imaging revealed a pituitary mass with suprasellar extension. Endocrine evaluation demonstrated hypopituitarism and arginine vasopressin (AVP) deficiency. The patient underwent transcranial resection under the presumptive diagnosis of a non-functioning PitNET; however, postoperative imaging showed lesion progression. Further investigation revealed positive C-ANCA and systemic features consistent with GPA. Histopathological reassessment with immunohistochemistry supported the diagnosis of granulomatous hypophysitis in the context of GPA. Induction therapy with cyclophosphamide achieved initial disease control, but pituitary relapse occurred during maintenance therapy with azathioprine, prompting treatment escalation to rituximab. Rituximab led to reduction of the pituitary mass and sustained clinical stability over four years. Persistent hypopituitarism required long-term hormone replacement. Pituitary involvement in GPA is an uncommon but important diagnostic challenge and may closely mimic a PitNET. This case highlights the need for careful integration of systemic clinical features, endocrine findings, imaging, and histopathological reassessment when evaluating sellar masses. Immunosuppressive therapy with cyclophosphamide and rituximab was effective in controlling pituitary involvement, although permanent pituitary hormone deficiencies may persist despite disease control.

Hyponatremia induced by hypopituitarism is an underrecognized complication in neurocritical care settings. This article presents a case of a patient with severe traumatic brain injury who developed euvolemic hyponatremia one month after the injury, accompanied by decreased serum osmolality. The hyponatremia remained refractory to conventional management, including fluid restriction and hypertonic saline supplementation. Subsequent endocrine evaluation confirmed hypopituitarism, characterized by markedly suppressed ACTH (<1 pg/ml) and low morning cortisol (1.68 μg/dl). Notably, serum sodium levels normalized following the initiation of exogenous hormone replacement. Our findings may represent an important but underrecognized cause of hyponatremia in neurocritical care patients, particularly those with severe acute brain injuries. Comprehensive testing for neuroendocrine hormones in this subset of patients is beneficial.

Programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitors and cytotoxic Lymphocyte-associated protein 4 (CTLA-4) inhibitors are the core classes of immune checkpoint inhibitors (ICIs) widely used in cancer treatment. These agents, including PD-1, PD-L1, and CTLA4 inhibitors, have demonstrated efficacy across multiple cancer types, enhancing progression free survival (PFS) and overall survival (OS). However, their use is associated with immune related adverse events (irAEs) that can manifest as skin rashes, hepatitis, diarrhea, colitis, hypopituitarism, and pneumonitis, among other conditions. In this systematic review, we discuss the safety and efficacy of ICIs based on 15 randomized controlled trials and cohort studies that met our eligibility criteria. All selected studies focused on analysing primary clinical outcomes including OS, PFS, objective response rate (ORR), and irAEs. These findings demonstrate that ICIs offer durable antitumor activity with favourable outcomes observed in patients with high tumour mutational burden (TMB) and PD-L1 expression. However, toxicity remains a significant concern, as some reports show substantial adverse events requiring immunosuppressive management. While PD-L1 expression and TMB are established biomarkers for predicting ICI response, their role in predicting immune-related adverse events remains investigational and is not supported by robust evidence. This review further examines combination strategies, including dual checkpoint blockade and ICI combined with chemotherapy, which have demonstrated superior clinical outcomes compared with monotherapy but are associated with increased toxicity. Future research should focus on refining patient selection criteria, optimizing toxicity management protocols, and identifying novel predictive biomarkers for ICI therapy. Understanding these aspects will facilitate the development of more effective ICI-based treatments with improved benefit-to-risk ratios, ultimately enhancing patient outcomes in oncology.

Adult medulloblastoma is a rare cerebellar tumour with an incidence of 0.6-1 per million per year in post-pubertal patients. Craniospinal radiotherapy is a key component of treatment. Endocrine organs commonly involved in the radiation field - such as the hypothalamus, pituitary and thyroid gland - are particularly sensitive to radiation-induced damage, often resulting in hormonal deficiencies in a dose-dependent manner. We report the case of a 43-year-old woman who developed both hypopituitarism and primary hypothyroidism following craniospinal radiotherapy for medulloblastoma at the age of 34. She was diagnosed with primary hypothyroidism two years later. Seven years later, hormonal substitution therapy was started for menopausal symptoms, and nine years later, she presented with persisting long-standing fatigue, amenorrhoea, nausea upon waking, vomiting and anorexia. Laboratory testing was suggestive of hypopituitarism. Dynamic testing confirmed severe growth hormone deficiency but a normal cortisol response. Thyroid-releasing hormone stimulation test revealed a blunted and delayed response. Magnetic resonance imaging revealed significantly reduced pituitary height over time. Although radiation-induced endocrine dysfunction is well documented in children, its prevalence in adult populations also reaches 50%, and its clinical significance is increasingly recognised. Despite the common occurrence of hypothalamic-pituitary axis dysfunction and primary hypothyroidism following craniospinal irradiation, their simultaneous presentation provides an important educational example of the complex and multifaceted endocrine effects of radiation exposure. This paper highlights the importance of minimising radiation dose on these endocrine glands, as well as long-term multidisciplinary follow-up and screening after craniospinal radiotherapy. It also raises the question whether pituitary evaluation on surveillance imaging could help predict pituitary dysfunction, a possibility that warrants further exploration.

Background and Clinical Significance: Osmotic demyelination syndrome (ODS) and pituitary apoplexy are rare but potentially severe neurological and endocrine complications that can arise in the context of profound metabolic stress. Case Presentation: We describe the case of a previously healthy 34-year-old man who developed severe symptomatic hyponatremia shortly after receiving his second dose of an mRNA COVID-19 vaccine. Initial laboratory findings and clinical assessment were consistent with syndrome of inappropriate antidiuretic hormone secretion. Following correction of serum sodium, the patient experienced neurological deterioration with gait disturbance, dysarthria, and cognitive impairment. Follow-up brain MRI demonstrated extrapontine osmotic demyelination involving the basal ganglia and thalamus, despite initially normal imaging. During subsequent endocrinological follow-up, pituitary MRI revealed pituitary apoplexy in a previously unrecognized adenoma, accompanied by evolving partial hypopituitarism. The patient was managed with careful electrolyte control and long-term hormone replacement therapy, including hydrocortisone, levothyroxine, and recombinant growth hormone, resulting in gradual functional and cognitive improvement. Conclusions: This case highlights the interaction between severe hyponatremia, osmotic stress, and pituitary vulnerability, and emphasizes the need for cautious sodium correction, careful interpretation of temporal associations, and continued clinical vigilance in the context of COVID-19 vaccination programs.