Summary

Severe hyponatremia and osmotic demyelination syndrome (ODS) are opposite ends of a spectrum of emergency disorders related to sodium concentrations. Management of severe hyponatremia is challenging because of the difficulty in balancing the risk of overcorrection leading to ODS as well as under-correction causing cerebral oedema, particularly in a patient with chronic hypocortisolism and hypothyroidism. We report a case of a patient with Noonan syndrome and untreated anterior hypopituitarism who presented with symptomatic hyponatremia and developed transient ODS.

Learning points:

• Patients with severe anterior hypopituitarism with severe hyponatremia are susceptible to the rapid rise of sodium level with a small amount of fluid and hydrocortisone.

• These patients with chronic anterior hypopituitarism are at high risk of developing ODS and therefore, care should be taken to avoid a rise of more than 4–6 mmol/L per day.

• Early recognition and rescue desmopressin and i.v. dextrose 5% fluids to reduce serum sodium concentration may be helpful in treating acute ODS.

Summary

Lymphocytic hypophysitis is a rare neuroendocrine disease characterised by an autoimmune inflammatory disorder of the pituitary gland. We report a 50-year-old woman who presented with headaches and bilateral sixth cranial nerve palsies. MRI of the pituitary revealed extensive fibrosis involving the sellar and extending into both cavernous sinuses causing bilateral occlusion of the internal carotid arteries (ICA). Transphenoidal biopsy confirmed the diagnosis of infiltrative fibrotic lymphocytic hypophysitis. Symptoms resolved with high dose of oral steroids but relapsed on tapering, requiring several treatments of i.v. pulse steroids over 8 months. Rituximab combined with mycophenolate mofetil was required to achieve long-term symptom relief. Serial MRI pituitary imaging showed stabilisation of her disease without reduction in sellar mass or regression of ICA occlusion. The patient’s brain remained perfused solely by her posterior circulation. This case demonstrates an unusual presentation of a rare disease and highlights a successful steroid-sparing regimen in a refractory setting.

Learning points:

• Lymphocytic hypophysitis is a rare inflammatory disorder of the pituitary gland. In exceptional cases, there is infiltration of the cavernous sinus with subsequent occlusion of the internal carotid arteries.

• First-line treatment of lymphocytic hypophysitis is high-dose glucocorticoids. Relapse after tapering or discontinuation is common and its use is limited by long-term adverse effects.

• There is a paucity of data for treatment of refractory lymphocytic hypophysitis. Goals of treatment should include improvement in symptoms, correction of hormonal insufficiencies, reduction in lesion size and prevention of recurrence.

• Steroid-sparing immunosuppressive drugs such as rituximab and mycophenolate mofetil have been successful in case reports. This therapeutic combination represents a viable alternative treatment for refractory disease.

Summary

Primary bilateral macronodular adrenal hyperplasia (PBMAH) is a rare cause of ACTH-independent Cushing syndrome (CS). This condition is characterized by glucocorticoid and/or mineralocorticoid excess, and is commonly regulated by aberrant G-protein coupled receptor expression may be subclinical, allowing the disease to progress for years undetected. Inhibin A is a glycoprotein hormone and tumor marker produced by certain endocrine glands including the adrenal cortex, which has not been previously investigated as a potential tumor marker for PBMAH. In the present report, serum inhibin A levels were evaluated in three patients with PBMAH before and after adrenalectomy. In all cases, serum inhibin A was elevated preoperatively and subsequently fell within the normal range after adrenalectomy. Additionally, adrenal tissues stained positive for inhibin A. We conclude that serum inhibin A levels may be a potential tumor marker for PBMAH.

Learning points:

• PBMAH is a rare cause of CS.

• PBMAH may have an insidious presentation, allowing the disease to progress for years prior to diagnosis.

• Inhibin A is a heterodimeric glycoprotein hormone expressed in the gonads and adrenal cortex.

• Inhibin A serum concentrations are elevated in some patients with PBMAH, suggesting the potential use of this hormone as a tumor marker.

• Further exploration of serum inhibin A concentration, as it relates to PBMAH disease progression, is warranted to determine if this hormone could serve as an early detection marker and/or predictor of successful surgical treatment.

Summary

A patient with atypical partial lipodystrophy who had a transient initial response to metreleptin experienced acute worsening of her metabolic state when neutralizing antibodies against metreleptin appeared. Because her metabolic status continued to deteriorate, a therapeutic trial with melanocortin-4 receptor agonist setmelanotide, that is believed to function downstream from leptin receptor in the leptin signaling system, was undertaken in an effort to improve her metabolic status for the first time in a patient with lipodystrophy. To achieve this, a compassionate use (investigational new drug application; IND) was initiated (NCT03262610). Glucose control, body fat by dual-energy X-ray absorptiometry and MRI, and liver fat by proton density fat fraction were monitored. Daily hunger scores were assessed by patient filled questionnaires. Although there was a slight decrease in hunger scales and visceral fat, stimulating melanocortin-4 receptor by setmelanotide did not result in any other metabolic benefit such as improvement of hypertriglyceridemia or diabetes control as desired. Targeting melanocortin-4 receptor to regulate energy metabolism in this setting was not sufficient to obtain a significant metabolic benefit. However, complex features of our case make it difficult to generalize these observations to all cases of lipodystrophy. It is still possible that melanocortin-4 receptor agonistic action may offer some therapeutic benefits in leptin-deficient patients.

Learning points:

• A patient with atypical lipodystrophy with an initial benefit with metreleptin therapy developed neutralizing antibodies to metreleptin (Nab-leptin), which led to substantial worsening in metabolic control. The neutralizing activity in her serum persisted for longer than 3 years.

• Whether the worsening in her metabolic state was truly caused by the development of Nab-leptin cannot be fully ascertained, but there was a temporal relationship. The experience noted in our patient at least raises the possibility for concern for substantial metabolic worsening upon emergence and persistence of Nab-leptin. Further studies of cases where Nab-leptin is detected and better assay systems to detect and characterize Nab-leptin are needed.

• The use of setmelanotide, a selective MC4R agonist targeting specific neurons downstream from the leptin receptor activation, was not effective in restoring metabolic control in this complex patient with presumed diminished leptin action due to Nab-leptin.

• Although stimulating the MC4R pathway was not sufficient to obtain a significant metabolic benefit in lowering triglycerides and helping with her insulin resistance as was noted with metreleptin earlier, there was a mild reduction in reported food intake and appetite.

• Complex features of our case make it difficult to generalize our observation to all leptin-deficient patients. It is possible that some leptin-deficient patients (especially those who need primarily control of food intake) may still theoretically benefit from MC4R agonistic action, and further studies in carefully selected patients may help to tease out the differential pathways of metabolic regulation by the complex network of leptin signaling system.

Summary

Central diabetes insipidus (CDI) and several endocrine disorders previously classified as idiopathic are now considered to be of an autoimmune etiology. Dermatomyositis (DM), a rare autoimmune condition characterized by inflammatory myopathy and skin rashes, is also known to affect the gastrointestinal, pulmonary, and rarely the cardiac systems and the joints. The association of CDI and DM is extremely rare. After an extensive literature search and to the best of our knowledge this is the first reported case in literature, we report the case of a 36-year-old male with a history of CDI, who presented to the hospital’s endocrine outpatient clinic for evaluation of a 3-week history of progressive facial rash accompanied by weakness and aching of the muscles.

Learning points:

• Accurate biochemical diagnosis should always be followed by etiological investigation.

• This clinical entity usually constitutes a therapeutic challenge, often requiring a multidisciplinary approach for optimal outcome.

• Dermatomyositis is an important differential diagnosis in patients presenting with proximal muscle weakness.

• Associated autoimmune conditions should be considered while evaluating patients with dermatomyositis.

• Dermatomyositis can relapse at any stage, even following a very long period of remission.

• Maintenance immunosuppressive therapy should be carefully considered in these patients.

Summary

Primary aldosteronism (PA) is more common than expected. Aberrant adrenal expression of luteinizing hormone (LH) receptor in patients with PA has been reported; however, its physiological role on the development of PA is still unknown. Herein, we report two unique cases of PA in patients with untreated Klinefelter’s syndrome, characterized as increased serum LH, suggesting a possible contribution of the syndrome to PA development. Case 1 was a 39-year-old man with obesity and hypertension since his 20s. His plasma aldosterone concentration (PAC) and renin activity (PRA) were 220 pg/mL and 0.4 ng/mL/h, respectively. He was diagnosed as having bilateral PA by confirmatory tests and adrenal venous sampling (AVS). Klinefelter’s syndrome was suspected as he showed gynecomastia and small testes, and it was confirmed on the basis of a low serum total testosterone level (57.3 ng/dL), high serum LH level (50.9 mIU/mL), and chromosome analysis. Case 2 was a 28-year-old man who had untreated Klinefelter’s syndrome diagnosed in his childhood and a 2-year history of hypertension and hypokalemia. PAC and PRA were 247 pg/mL and 0.3 ng/mL/h, respectively. He was diagnosed as having a 10 mm-sized aldosterone-producing adenoma (APA) by AVS. In the APA, immunohistochemical analysis showed co-expression of LH receptor and CYP11B2. Our cases of untreated Klinefelter’s syndrome complicated with PA suggest that increased serum LH levels and adipose tissues, caused by primary hypogonadism, could contribute to PA development. The possible complication of PA in hypertensive patients with Klinefelter’s syndrome should be carefully considered.

Learning points:

• The pathogenesis of primary aldosteronism is still unclear.

• Expression of luteinizing hormone receptor has been reported in aldosterone-producing adenoma.

• Serum luteinizing hormone, which is increased in patients with Klinefelter’s syndrome, might contribute to the development of primary aldosteronism.

Summary

Primary amenorrhea could be caused by disorders of four parts: disorders of the outflow tract, disorders of the ovary, disorders of the anterior pituitary, and disorders of hypothalamus. Delay in diagnosis and hormone substitution therapy causes secondary osteoporosis. Herein, we report a case of a 23-year-old phenotypical female who presented with primary amenorrhea from 46, XX gonadal dysgenesis but had been misdiagnosed as Mayer–Rokitansky–Kuster–Hauser (MRKH) syndrome or Mullerian agenesis. The coexistence of gonadal dysgenesis and MRKH was suspected after laboratory and imaging investigations. However, the vanishing uterus reappeared after 18 months of hormone replacement therapy. Therefore, hormone profiles and karyotype should be thoroughly investigated to distinguish MRKH syndrome from other disorders of sex development (DSD). Double diagnosis of DSD is extremely rare and periodic evaluation should be reassessed. This case highlights the presence of estrogen deficiency state, the uterus may remain invisible until adequate exposure to exogenous estrogen.

Learning points:

• An early diagnosis of disorders of sex development (DSD) is extremely important in order to promptly begin treatment, provide emotional support to the patient and reduce the risks of associated complications.

• Hormone profiles and karyotype should be investigated in all cases of the presumptive diagnosis of Mayer–Rokitansky–Kuster–Hauser (MRKH) syndrome or Mullerian agenesis.

• The association between 46, XX gonadal dysgenesis and Mullerian agenesis has been occasionally reported as a co-incidental event; however, reassessment of the presence of uterus should be done again after administration of exogenous estrogen replacement for at least 6–12 months.

• A multidisciplinary approach is necessary for patients presenting with DSD to ensure appropriate treatments and follow-up across the lifespan of individuals with DSD.

Summary

ACTH-secreting pheochromocytoma is a very rare cause of Cushing’s syndrome, with a high morbidity and mortality risk due to both cortisol and catecholamines excess. We report the case of a 45-year-old female patient with a 3 cm, high-density, left adrenal mass, diagnosed as an ACTH-secreting pheochromocytoma. The biochemical sensitivity of the tumor to somatostatin analogues was tested by a 100 μg s.c. octreotide administration, which led to an ACTH and cortisol reduction of 50 and 25% respectively. In addition to alpha and beta blockers, preoperative approach to laparoscopic adrenalectomy included octreotide, a somatostatin analogue, together with ketoconazole, in order to achieve an adequate pre-surgical control of cortisol release. Histopathological assessment confirmed an ACTH-secreting pheochromocytoma expressing type 2 and 5 somatostatin receptors (SSTR-2 and -5).

Learning points:

• ACTH-secreting pheochromocytomas represent a rare and severe condition, characterized by high morbidity and mortality risk.

• Surgical removal of the adrenal mass is the gold standard treatment, but adequate medical therapy is required preoperatively to improve the surgical outcome and to avoid major complications.

• Somatostatin analogs, in addition to other medications, may represent a useful therapeutic option for the presurgical management of selected patients.

• In this sense, the octreotide challenge test is a useful tool to predict favorable therapeutic response to the treatment.

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

Summary

Silent corticotroph adenoma (SCA) is an unusual type of nonfunctioning pituitary adenoma (NFA) that is silent both clinically and biochemically and can only be recognized by positive immunostaining for ACTH. Under rare circumstances, it can transform into hormonally active disease presenting with severe Cushing syndrome. It might often produce diagnostic dilemma with difficult management issue if not thoroughly investigated and subtyped accordingly following surgery. Here, we present a 21-year-old male who initially underwent pituitary adenomectomy for presumed NFA with compressive symptoms. However, he developed recurrent and invasive macroadenoma with severe clinical as well as biochemical hypercortisolism during post-surgical follow-up. Repeat pituitary surgery was carried out urgently as there was significant optic chiasmal compression. Immunohistochemical analysis of the tumor tissue obtained on repeat surgery proved it to be an aggressive corticotroph adenoma. Though not cured, he showed marked clinical and biochemical improvement in the immediate postoperative period. Anticipating recurrence from the residual tumor, we referred him for cyber knife radio surgery.

Learning points:

• Pituitary NFA commonly present with compressive symptoms such as headache and blurred vision.

• Post-surgical development of Cushing syndrome in such a case could be either drug induced or endogenous.

• In the presence of recurrent pituitary tumor, ACTH-dependent Cushing syndrome indicates CD.

• Rarely a SCA presenting initially as NFA can transform into an active corticotroph adenoma.

• Immunohistochemical marker for ACTH in the resected tumor confirms the diagnosis.