Summary

Whilst literature is expanding on pasireotide use in the management of Cushing’s disease (CD), there is still currently much unknown about long-term and low-dose pasireotide use in CD. We present a 60-year-old female with residual CD after transphenoidal surgery (TSS), being successfully managed with S.C. pasireotide for over 10 years. For 6 years, her S.C. pasireotide was inadvertently administered at 360 µg twice daily (BID), almost half the recommended dose of 600 µg BID. Despite the low-dose, her urinary free cortisol (UFC) normalised within 6 months and Cushingoid features resolved. She remained in biochemical and clinical remission on the same low-dose for 6 years, before a medication audit discovered her mistaken dose and directed her to take 600 µg BID. With the higher dose 600 µg BID for the next 5 years, her glycaemia worsened without any changes in her UFC and residual tumour volume. Our case showed the continuing effectiveness and safety of treatment with S.C. pasireotide for more than 10 years, and that a low-dose regimen may be considered an option for responders by its safety profile.

Learning points:

• A lower dose of pasireotide may be effective in the initial treatment of CD than the recommended 600 µg BID dosage, though more studies are required to explore this.

• Low-dose pasireotide use has the benefit of minimising adverse effects.

• In the long-term, pasireotide has a sustained clinical and biochemical effect and is well tolerated.

Summary

Single-minded homolog 1 (SIM1) is a transcription factor that plays a role in the development of both the hypothalamus and pituitary. SIM1 gene mutations are known to cause obesity in humans, and chromosomal deletions encompassing SIM1 and other genes necessary for pituitary development can cause a Prader–Willi-like syndrome with obesity and hypopituitarism. There have been no reported cases of hypopituitarism linked to a single SIM1 mutation. A 21-month-old male presented to endocrinology clinic with excessive weight gain and severe obesity. History was also notable for excessive drinking and urination. Endocrine workup revealed central hypothyroidism, partial diabetes insipidus, and central adrenal insufficiency. Genetic evaluation revealed a novel mutation in the SIM1 gene. No other genetic abnormalities to account for his obesity and hypopituitarism were identified. While we cannot definitively state this mutation is pathogenic, it is notable that SIM1 plays a role in the development of all three of the patient’s affected hormone axes. He is now 6 years old and remains on treatment for his pituitary hormone deficiencies and continues to exhibit excessive weight gain despite lifestyle interventions.

Learning points:

• Mutations in SIM1 are a well-recognized cause of monogenic human obesity, and there have been case reports of Prader–Willi-like syndrome and hypopituitarism in patients with chromosomal deletions that contain the SIM1 gene.

• SIM1 is expressed during the development of the hypothalamus, specifically in neuroendocrine lineages that give rise to the hormones oxytocin, arginine vasopressin, thyrotropin-releasing hormone, corticotropin-releasing hormone, and somatostatin.

• Pituitary testing should be considered in patients with severe obesity and a known genetic abnormality affecting the SIM1 gene, particularly in the pediatric population.

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

Renovascular hypertension (RVHT) is an important and potentially treatable form of resistant hypertension. Hypercortisolemia could also cause hypertension and diabetes mellitus. We experienced a case wherein adrenalectomy markedly improved blood pressure and plasma glucose levels in a patient with RVHT and low-level autonomous cortisol secretion. A 62-year-old Japanese man had been treated for hypertension and diabetes mellitus for 10 years. He was hospitalized because of a disturbance in consciousness. His blood pressure (BP) was 236/118 mmHg, pulse rate was 132 beats/min, and plasma glucose level was 712 mg/dL. Abdominal CT scanning revealed the presence of bilateral adrenal masses and left atrophic kidney. Abdominal magnetic resonance angiography demonstrated marked stenosis of the left main renal artery. The patient was subsequently diagnosed with atherosclerotic RVHT with left renal artery stenosis. His left adrenal lobular mass was over 40 mm and it was clinically suspected the potential for cortisol overproduction. Therefore, laparoscopic left nephrectomy and adrenalectomy were simultaneously performed, resulting in improved BP and glucose levels. Pathological studies revealed the presence of multiple cortisol-producing adrenal nodules and aldosterone-producing cell clusters in the adjacent left adrenal cortex. In the present case, the activated renin-angiotensin-aldosterone system and cortisol overproduction resulted in severe hypertension, which was managed with simultaneous unilateral nephrectomy and adrenalectomy.

Learning points:

• Concomitant activation of the renin-angiotensin-aldosterone system and cortisol overproduction may contribute to the development of severe hypertension and lead to lethal cardiovascular complications.

• Treatment with simultaneous unilateral nephrectomy and adrenalectomy markedly improves BP and blood glucose levels.

• CYP11B2 immunohistochemistry staining revealed the existence of aldosterone-producing cell clusters (APCCs) in the adjacent non-nodular adrenal gland, suggesting that APCCs may contribute to aldosterone overproduction in patients with RVHT.

Summary

Isolated, adult-onset central hypothyroidism is very rare, and its diagnosis can be challenging. A 42-year-old patient was referred for evaluation of a 2.8 cm thyroid nodule. She referred symptoms that could be attributed to hypothyroidism and thyroid tests showed low TSH and normal-low levels of free T4. However, evaluation of the remaining pituitary hormones and pituitary MRI were normal, yet a radionuclide scanning revealed that the thyroid nodule was ‘hot’ and the tracer uptake in the remaining thyroid tissue was suppressed. Interpretation of these studies led to a misdiagnosis of subclinical hyperthyroidism and the patient was treated with radioiodine. Soon after treatment, she developed a frank hypothyroidism without appropriate elevation of TSH and the diagnosis of central hypothyroidism was made a posteriori. Long term follow-up revealed a progressive pituitary failure, with subsequent deficiency of ACTH and GH. This case should alert to the possibility of overlooking central hypothyroidism in patients simultaneously bearing primary thyroid diseases able to cause subclinical hyperthyroidism.

Learning points:

• Although rarely, acquired central hypothyroidism can occur in the absence of other pituitary hormone deficiencies.

• In these cases, diagnosis is challenging, as symptoms are unspecific and usually mild, and laboratory findings are variable, including low, normal or even slightly elevated TSH levels, along with low or low-normal concentrations of free T4.

• In cases with low TSH levels, the coexistence of otherwise common disorders able to cause primary thyroid hyperfunction, such as autonomous nodular disease, may lead to a misdiagnosis of subclinical hyperthyroidism.

Summary

Cushing’s disease is a rare disorder characterised by excessive cortisol production as a consequence of a corticotroph pituitary tumour. While the primary treatment is surgical resection, post-operative radiation therapy may be used in cases of ongoing inadequate hormonal control or residual or progressive structural disease. Despite improved outcomes, radiotherapy for pituitary tumours is associated with hypopituitarism, visual deficits and, rarely, secondary malignancies. We describe an unusual case of a 67-year-old female with presumed Cushing’s disease diagnosed at the age of 37, treated with transsphenoidal resection of a pituitary tumour with post-operative external beam radiotherapy (EBRT), ketoconazole for steroidogenesis inhibition, and finally bilateral adrenalectomy for refractory disease. She presented 30 years after her treatment with a witnessed generalised tonic-clonic seizure. Radiological investigations confirmed an extracranial mass infiltrating through the temporal bone and into brain parenchyma. Due to recurrent generalised seizures, the patient was intubated and commenced on dexamethasone and anti-epileptic therapy. Resection of the tumour revealed a high-grade osteoblastic osteosarcoma. Unfortunately, the patient deteriorated in intensive care and suffered a fatal cardiac arrest following a likely aspiration event. We describe the risk factors, prevalence and treatment of radiation-induced osteosarcoma, an exceedingly rare and late complication of pituitary irradiation. To our knowledge, this is the longest reported latency period between pituitary irradiation and the development of an osteosarcoma of the skull.

Learning points:

• Cushing’s disease is treated with transsphenoidal resection as first-line therapy, with radiotherapy used in cases of incomplete resection, disease recurrence or persistent hypercortisolism.

• The most common long-term adverse outcome of pituitary tumour irradiation is hypopituitarism occurring in 30–60% of patients at 10 years, and less commonly, vision loss and oculomotor nerve palsies, radiation-induced brain tumours and sarcomas.

• Currently proposed characteristics of radiation-induced osteosarcomas include: the finding of a different histological type to the primary tumour, has developed within or adjacent to the path of the radiation beam, and a latency period of at least 3 years.

• Treatment of osteosarcoma of the skull include complete surgical excision, followed by systemic chemotherapy and/or radiotherapy.

• Overall prognosis in radiation-induced sarcoma of bone is poor.

• Newer techniques such as stereotactic radiosurgery may reduce the incidence of radiation-induced malignancies.

Summary

The etiology of hyponatremia is assessed based on urine osmolality and sodium. We herein describe a 35-year-old Asian man with pulmonary tuberculosis and perforated duodenal ulcer who presented with hyponatremia with hourly fluctuating urine osmolality ranging from 100 to 600 mosmol/kg, which resembled urine osmolality observed in typical polydipsia and SIADH simultaneously. Further review revealed correlation of body temperature and urine osmolality. Since fever is a known non-osmotic stimulus of ADH secretion, we theorized that hyponatremia in this patient was due to transient ADH secretion due to fever. In our case, empiric exogenous glucocorticoid suppressed transient non-osmotic ADH secretion and urine osmolality showed highly variable concentrations. Transient ADH secretion-related hyponatremia may be underrecognized due to occasional empiric glucocorticoid administration in patients with critical illnesses. Repeatedly monitoring of urine chemistries and interpretation of urine chemistries with careful review of non-osmotic stimuli of ADH including fever is crucial in recognition of this etiology.

Learning points:

• Hourly fluctuations in urine osmolality can be observed in patients with fever, which is a non-osmotic stimulant of ADH secretion.

• Repeated monitoring of urine chemistries aids in the diagnosis of the etiology underlying hyponatremia, including fever, in patients with transient ADH secretion.

• Glucocorticoid administration suppresses ADH secretion and improves hyponatremia even in the absence of adrenal insufficiency; the etiology of hyponatremia should be determined carefully in these patients.

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

Multiple endocrine metastases are a rare but possible complication of lung adenocarcinoma (LAC). Pituitary metastasis is a rare condition with poor clinical expression. Diabetes insipidus (DI) is its most common presenting symptom. Here we report an original case of a pituitary stalk (PS) metastasis from LAC presenting as central DI followed by adrenal insufficiency (AI) from bilateral adrenal metastasis, without known evidence of the primary malignancy. A 45-year-old woman whose first clinical manifestations were polyuria and polydipsia was admitted. She was completely asymptomatic with no cough, no weight loss or anorexia. Chest radiography was normal. Brain MRI showed a thick pituitary stalk (PS). DI was confirmed by water restriction test and treated with vasopressin with great clinical results. Explorations for systemic and infectious disease were negative. Few months later, an acute AI led to discovering bilateral adrenal mass on abdominal CT. A suspicious 2.3 cm apical lung nodule was found later. Histopathological adrenal biopsy revealed an LAC. The patient received systemic chemotherapy with hormonal replacement for endocrinological failures by both vasopressin and hydrocortisone. We present this rare case of metastatic PS thickness arising from LAC associated with bilateral adrenal metastasis. Screening of patients with DI and stalk thickness for lung and breast cancer must be considered. Multiple endocrine failures as a diagnostic motive of LAC is a rare but possible circumstance.

Learning points:

• Adrenal metastasis is a common location in lung adenocarcinoma; however, metastatic involvement of the pituitary stalk remains a rare occurrence, especially as a leading presentation to diagnose lung cancer.

• The posterior pituitary and the infundibulum are the preferential sites for metastases, as they receive direct arterial blood supply from hypophyseal arteries.

• Patients diagnosed with diabetes insipidus due to pituitary stalk thickness should be considered as a metastasis, after exclusion of the classical systemic and infectious diseases.

• The diagnosis of an endocrinological metastatic primary lung adenocarcinoma for patients without respiratory symptoms is often delayed due to a lack of correlation between endocrinological symptoms and lung cancer.

• The main originality of our case is the concomitant diagnosis of both endocrinological failures, as it was initiated with a diabetes insipidus and followed by an acute adrenal insufficiency.

Summary

Cushing’s syndrome is an endocrine disorder that causes anovulatory infertility secondary to hypercortisolism; therefore, pregnancy rarely occurs during its course. We present the case of a 24-year-old, 16-week pregnant female with a 10-month history of unintentional weight gain, dorsal gibbus, nonpruritic comedones, hirsutism and hair loss. Initial biochemical, hormonal and ultrasound investigations revealed hypokalemia, increased nocturnal cortisolemia and a right adrenal mass. The patient had persistent high blood pressure, hyperglycemia and hypercortisolemia. She was initially treated with antihypertensive medications and insulin therapy. Endogenous Cushing’s syndrome was confirmed by an abdominal MRI that demonstrated a right adrenal adenoma. The patient underwent right laparoscopic adrenalectomy and anatomopathological examination revealed an adrenal adenoma with areas of oncocytic changes. Finally, antihypertensive medication was progressively reduced and glycemic control and hypokalemia reversal were achieved. Long-term therapy consisted of low-dose daily prednisone. During follow-up, despite favorable outcomes regarding the patient’s Cushing’s syndrome, stillbirth was confirmed at 28 weeks of pregnancy. We discuss the importance of early diagnosis and treatment of Cushing’s syndrome to prevent severe maternal and fetal complications.

Learning points:

• Pregnancy can occur, though rarely, during the course of Cushing’s syndrome.

• Pregnancy is a transient physiological state of hypercortisolism and it must be differentiated from Cushing’s syndrome based on clinical manifestations and laboratory tests.

• The diagnosis of Cushing’s syndrome during pregnancy may be challenging, particularly in the second and third trimesters because of the changes in the maternal hypothalamic-pituitary-adrenal axis.

• Pregnancy during the course of Cushing’s syndrome is associated with severe maternal and fetal complications; therefore, its early diagnosis and treatment is critical.