Vasopressin and Its Analogues: From Natural Hormones to Multitasking Peptides.

Human neurohormone vasopressin (AVP) is synthesized in overlapping regions in the hypothalamus. It is mainly known for its vasoconstricting abilities, and it is responsible for the regulation of plasma osmolality by maintaining fluid homeostasis. Over years, many attempts have been made to modify this hormone and find AVP analogues with different pharmacological profiles that could overcome its limitations. Non-peptide AVP analogues with low molecular weight presented good affinity to AVP receptors. Natural peptide counterparts, found in animals, are successfully applied as therapeutics; for instance, lypressin used in treatment of diabetes insipidus. Synthetic peptide analogues compensate for the shortcomings of AVP. Desmopressin is more resistant to proteolysis and presents mainly antidiuretic effects, while terlipressin is a long-acting AVP analogue and a drug recommended in the treatment of varicose bleeding in patients with liver cirrhosis. Recently published results on diverse applications of AVP analogues in medicinal practice, including potential lypressin, terlipressin and ornipressin in the treatment of SARS-CoV-2, are discussed.

Atorvastatin does not ameliorate nephrogenic diabetes insipidus induced by lithium or potassium depletion in mice.

Acquired forms of nephrogenic diabetes insipidus (NDI) include lithium (Li)-induced and hypokalemia-induced NDI. Both forms are associated with AQP2 downregulation and collecting duct (CD) cellular remodeling. Statins are cholesterol-lowering drugs appearing to increase AQP2 membrane-translocation and improve urine concentration in other NDI models. We have investigated if statins are able to prevent or rescue the Li-induced changes in mice and in a mouse cortical CD cell line (mCCDc1l ). Biotinylation assays showed that acute (1hr) atorvastatin, simvastatin, or fluvastatin increased AQP2 membrane accumulation in mCCDc1l cells showing that the cell line responds to acute statin treatment. To see whether chronic statin treatment abolish the Li effects, mCCDc1l cells were treated with 48 h Li, combined Li/atorvastatin or combined Li/simvastatin. Li reduced AQP2, but combined Li/atorvastatin or Li/simvastatin did not prevent AQP2 downregulation. In mice, chronic (21 days) Li increased urine output and reduced urine osmolality, but combined Li/atorvastatin did not prevent these effects. In inner medulla (IM), Li reduced total AQP2 and increased pS261-AQP2. Combined Li/atorvastatin did not abolish these changes. Atorvastatin did not prevent a Li-induced increase in intercalated cells and proliferation in IM. In mice with already established NDI, atorvastatin had no effect on the Li-induced changes either. Mice subjected to 14 days of potassium-deficient diet developed polyuria and AQP2 downregulation in IM. Co-treatment with atorvastatin did not prevent this. In conclusion, atorvastatin does not appear to be able to prevent or rescue Li-NDI or to prevent hypokalemic-induced NDI.

Sorting Nexin 27 Regulates the Lysosomal Degradation of Aquaporin-2 Protein in the Kidney Collecting Duct.

Sorting nexin 27 (SNX27), a PDZ (Postsynaptic density-95/Discs large/Zonula occludens 1) domain-containing protein, cooperates with a retromer complex, which regulates intracellular trafficking and the abundance of membrane proteins. Since the carboxyl terminus of aquaporin-2 (AQP2c) has a class I PDZ-interacting motif (X-T/S-X-Φ), the role of SNX27 in the regulation of AQP2 was studied. Co-immunoprecipitation assay of the rat kidney demonstrated an interaction of SNX27 with AQP2. Glutathione S-transferase (GST) pull-down assays revealed an interaction of the PDZ domain of SNX27 with AQP2c. Immunocytochemistry of HeLa cells co-transfected with FLAG-SNX27 and hemagglutinin (HA)-AQP2 also revealed co-localization throughout the cytoplasm. When the PDZ domain was deleted, punctate HA-AQP2 labeling was localized in the perinuclear region. The labeling was intensively overlaid by Lysotracker staining but not by GM130 labeling, a cis-Golgi marker. In rat kidneys and primary cultured inner medullary collecting duct cells, the subcellular redistribution of SNX27 was similar to AQP2 under 1-deamino-8-D-arginine vasopressin (dDAVP) stimulation/withdrawal. Cell surface biotinylation assay showed that dDAVP-induced AQP2 translocation to the apical plasma membrane was unaffected after SNX27 knockdown in mpkCCD cells. In contrast, the dDAVP-induced AQP2 protein abundance was significantly attenuated without changes in AQP2 mRNA expression. Moreover, the AQP2 protein abundance was markedly declined during the dDAVP withdrawal period after stimulation under SNX27 knockdown, which was inhibited by lysosome inhibitors. Autophagy was induced after SNX27 knockdown in mpkCCD cells. Lithium-induced nephrogenic diabetes insipidus in rats revealed a significant downregulation of SNX27 in the kidney inner medulla. Taken together, the PDZ domain-containing SNX27 interacts with AQP2 and depletion of SNX27 contributes to the autophagy-lysosomal degradation of AQP2.

Effects of extreme potassium stress on blood pressure and renal tubular sodium transport.

We characterized mouse blood pressure and ion transport in the setting of commonly used rodent diets that drive K+ intake to the extremes of deficiency and excess. Male 129S2/Sv mice were fed either K+-deficient, control, high-K+ basic, or high-KCl diets for 10 days. Mice maintained on a K+-deficient diet exhibited no change in blood pressure, whereas K+-loaded mice developed an ~10-mmHg blood pressure increase. Following challenge with NaCl, K+-deficient mice developed a salt-sensitive 8 mmHg increase in blood pressure, whereas blood pressure was unchanged in mice fed high-K+ diets. Notably, 10 days of K+ depletion induced diabetes insipidus and upregulation of phosphorylated NaCl cotransporter, proximal Na+ transporters, and pendrin, likely contributing to the K+-deficient NaCl sensitivity. While the anionic content with high-K+ diets had distinct effects on transporter expression along the nephron, both K+ basic and KCl diets had a similar increase in blood pressure. The blood pressure elevation on high-K+ diets correlated with increased Na+-K+-2Cl- cotransporter and γ-epithelial Na+ channel expression and increased urinary response to furosemide and amiloride. We conclude that the dietary K+ maneuvers used here did not recapitulate the inverse effects of K+ on blood pressure observed in human epidemiological studies. This may be due to the extreme degree of K+ stress, the low-Na+-to-K+ ratio, the duration of treatment, and the development of other coinciding events, such as diabetes insipidus. These factors must be taken into consideration when studying the physiological effects of dietary K+ loading and depletion.

Integrated metabolome analysis reveals novel connections between maternal fecal metabolome and the neonatal blood metabolome in women with gestational diabetes mellitus.

Gestational Diabetes Mellitus (GDM), which is correlated with changes in the gut microbiota, is a risk factor for neonatal inborn errors of metabolism (IEMs). Maternal hyperglycemia exerts epigenetic effects on genes that encode IEM-associated enzymes, resulting in changes in the neonatal blood metabolome. However, the relationship between maternal gut microbiota and the neonatal blood metabolome remains poorly understood. This study aimed at understanding the connections between maternal gut microbiota and the neonatal blood metabolome in GDM. 1H-NMR-based untargeted metabolomics was performed on maternal fecal samples and targeted metabolomics on the matched neonatal dry blood spots from a cohort of 40 pregnant women, including 22 with GDM and 18 controls. Multi-omic association methods (including Co-Inertia Analysis and Procrustes Analysis) were applied to investigate the relationship between maternal fecal metabolome and the neonatal blood metabolome. Both maternal fecal metabolome and the matched neonatal blood metabolome could be separated along the vector of maternal hyperglycemia. A close relationship between the maternal and neonatal metabolomes was observed by multi-omic association approaches. Twelve out of thirty-two maternal fecal metabolites with altered abundances from 872 1H- NMR features (Bonferroni-adjusted P < 0.05) in women with GDM and the controls were identified, among which 8 metabolites contribute (P < 0.05 in a 999-step permutation test) to the close connection between maternal and the neonatal metabolomes in GDM. Four of these eight maternal fecal metabolites, including lysine, putrescine, guanidinoacetate, and hexadecanedioate, were negatively associated (Spearman rank correlation, coefficient value < -0.6, P < 0.05) with maternal hyperglycemia. Biotin metabolism was enriched (Bonferroni-adjusted P < 0.05 in the hypergeometric test) with the four-hyperglycemia associated fecal metabolites. The results of this study suggested that maternal fecal metabolites contribute to the connections between maternal fecal metabolome and the neonatal blood metabolome and may further affect the risk of IEMs.

Trametinib Toxicities in Patients With Low-grade Gliomas and Diabetes Insipidus: Related Findings?

Low-grade gliomas (LGG) represent the most common form of primary central nervous system tumor arising in childhood. There is growing evidence to support the role of the mitogen-activated protein kinase pathway in driving tumor growth and MEK inhibitors are being investigated in clinical trials for refractory and unresectable LGGs. As MEK inhibitors progress through clinical trials, drug toxicities have been identified. We report on 2 pediatric patients with LGG and known diabetes insipidus who developed severe hyponatraemia associated with significant decreases in desmopressin doses after starting trametinib. We review potential mechanisms for this sodium imbalance by examining the interaction between MEK inhibition and aquaporin channel physiology. We recommend close monitoring of serum sodium levels and clinical status in patients with diabetes insipidus who have optic-hypothalamic gliomas and are started on treatment with MEK inhibitors.

Vasopressin and Copeptin in health and disease.

Arginine Vasopressin (AVP) and copeptin derive from the same precursor molecule. Due to the equimolar secretion, copeptin responds as rapidly as AVP to osmotic, hemodynamic and unspecific stress-related stimuli and both peptides show a very strong correlation. The physiological functions of AVP are homeostasis of fluid balance, vascular tonus and regulation of the endocrine stress response. In contrast, the exact function of copeptin remains unknown. Since copeptin, in contrast to AVP, can easily be measured with a sandwich immunoassay, its main function so far that it indirectly indicates the amount of AVP in the circulation. Copeptin has emerged as a useful measure in different diseases. On one hand, through its characteristics as a marker of stress, it provides a unique measure of the individual stress burden. As such, it is a prognostic marker in different acute diseases such as ischemic stroke or myocardial infarction. On the other side, it has emerged as a promising marker in the diagnosis of AVP-dependent fluid disorders. Copeptin reliably differentiates various entities of the polyuria polydipsia syndrome; baseline levels >20 pmol/L without prior fluid deprivation identify patients with nephrogenic diabetes insipidus, whereas levels measured upon osmotic stimulation with hypertonic saline or upon non-osmotic stimulation with arginine differentiate primary polydipsia from central diabetes insipidus. In patients with hyponatremia, low levels of copeptin together with low urine osmolality identify patients with primary polydipsia, but copeptin levels overlap in all other causes of hyponatremia, limiting its diagnostic use in hyponatremia. Copeptin has also been put forward as predictive marker for autosomal dominant polycystic kidney disease and for diabetes mellitus, but more studies are needed to confirm these findings.

Renal response to an oral protein load in patients with central diabetes insipidus before and after treatment with vasopressin.

AIM: Different factors have been hypothesized to play a role in the cascade of events associated with the protein-induced glomerular response. However, scant data are available on the possible functional effect of vasopressin (VP) on the glomerular filtration rate (GFR) in humans with central diabetes insipidus (CDI), which was the aim of the present study. METHOD: Renal function was studied under fasting conditions (baseline) and after a meat meal in 16 patients with CDI before and after treatment with desmopressin (DDAVP) and in 16 control subjects. GFR was measured by the inulin method. RESULTS: At baseline, the GFR was lower in patients with CDI. Treatment with DDAVP resulted in an insignificant increase in GFR, which was not statistically different from untreated patients. After an acute oral protein load, the GFR increased, peaking at 45 min post meal in controls, and at 135 min post meal in treated and untreated CDI patients. CONCLUSION: After a meat meal, the peak GFR response is delayed in CDI patients suggesting that VP might indirectly affect tubule-glomerular feedback.

Neuroendocrine changes after aneurysmal subarachnoid haemorrhage.

INTRODUCTION: The prevalence of pituitary dysfunction is high following aneurysmal subarachnoid hemorrhage (aSAH) and when occurs it may contribute to residual symptoms of aSAH such as decreased cognition and quality of life. Hypopituitarism following aSAH may have non-specific, subtle symptoms and potentially serious consequences if remained undiagnosed. METHODS: We reviewed the literature on epidemiology, pathophysiology, diagnostic methods and management of neuroendocrine changes after aSAH as well as on the impact of pituitary dysfunction on outcome of the patient. RESULTS: The prevalence rates of pituitary dysfunction after aSAH varies greatly across studies due to different diagnostic methods, though growth hormone deficiency is generally the most frequently reported followed by adrenocorticotropic hormone, gonadotropin and thyroid stimulating hormone deficiencies. Pituitary deficiency tends to improve over time after aSAH but new onset deficiencies in chronic phase may also occur. There are no clinical parameters to predict the presence of hypopituitarism after aSAH. Age of the patient and surgical procedures are risk factors associated with development of hypopituitarism but the effect of pituitary dysfunction on outcome of the patient is not clear. Replacement of hypocortisolemia and hypothyroidism is essential but treatment of other hormonal insufficiencies should be individualized. CONCLUSIONS: Hypopituitarism following aSAH necessitates screening despite lack of gold standard evaluation tests and cut-off values in the follow up, because missed diagnosis may lead to untoward consequences.

Posterior pituitary dysfunction following traumatic brain injury: review.

Neurohypophysial dysfunction is common in the first days following traumatic brain injury (TBI), manifesting as dysnatremia in approximately 1 in 4 patients. Both hyponatremia and hypernatremia can impair recovery from TBI and in the case of hypernatremia, there is a significant association with excess mortality. Hyponatremia secondary to syndrome of inappropriate antidiuretic hormone secretion (SIAD) is the commonest electrolyte disturbance following TBI. Acute adrenocorticotropic hormone (ACTH)/cortisol deficiency occurs in 10-15% of TBI patients and can present with a biochemical picture identical to SIAD. For this reason, exclusion of glucocorticoid deficiency is of particular importance in post-TBI SIAD. Cerebral salt wasting is a rare cause of hyponatremia following TBI. Hyponatremia predisposes to seizures, reduced consciousness, and prolonged hospital stay. Diabetes insipidus (DI) occurs in 20% of cases following TBI; where diminished consciousness is present, appropriate fluid replacement of renal water losses is occasionally inadequate, leading to hypernatremia. Hypernatremia is strongly predictive of mortality following TBI. Most cases of DI are transient, but persistent DI is also predictive of mortality, irrespective of plasma sodium concentration. Persistent DI may herald rising intracranial pressure due to coning. True adipsic DI is rare following TBI, but patients are vulnerable to severe hypernatremic dehydration, exacerbation of neurologic deficits and hypothalamic complications, therefore clinicians should be aware of this possible variant of DI.

The Paraventricular Nucleus of the Hypothalamus: Development, Function, and Human Diseases.

The paraventricular nucleus of the hypothalamus (PVH), located in the ventral diencephalon adjacent to the third ventricle, is a highly conserved brain region present in species from zebrafish to humans. The PVH is composed of three main types of neurons, magnocellular, parvocellular, and long-projecting neurons, which play imperative roles in the regulation of energy balance and various endocrinological activities. In this review, we focus mainly on recent findings about the early development of the hypothalamus and the PVH, the functions of the PVH in the modulation of energy homeostasis and in the hypothalamus-pituitary system, and human diseases associated with the PVH, such as obesity, short stature, hypertension, and diabetes insipidus. Thus, the investigations of the PVH will benefit not only understanding of the development of the central nervous system but also the etiology of and therapy for human diseases.

Pituitary dysfunction in granulomatosis with polyangiitis.

PURPOSE: Granulomatosis with polyangiitis (GPA) is a multisystem disease, characterized by necrotizing small-vessel vasculitis, which mainly affects the respiratory tract and the kidneys. Pituitary involvement in GPA is rare, present in about 1% of all cases of GPA. To date, only case reports or small case series have been published. Herein we report clinical features, imaging findings, treatment and outcomes in three patients with GPA-related pituitary dysfunction (PD). METHODS: A retrospective analysis of three cases of GPA-related PD was conducted, followed by systematic review of the English medical literature using PubMed. RESULTS: The three cases include three women aged between 32 and 37 years. PD was the presenting feature in one and two developed PD in the course of the disease. All patients had a pituitary lesion on MRI. Conventional treatment with high doses of glucocorticoids and cyclophosphamide led to resolution or improvement of the MRI abnormalities, whereas it was not effective in restoring PD. A systematic review identified 51 additional patients, showing that GPA can lead to partial or global PD, either at onset or, during the course of the disease. Secondary hypogonadism is the predominant manifestation, followed by diabetes insipidus (DI). Sellar mass with central cystic lesion is the most frequent radiological finding. CONCLUSION: GPA should be carefully considered in patients with a sellar mass and unusual clinical presentation with DI and systemic disease. Although conventional induction-remission treatment improves systemic symptoms and radiological pituitary abnormalities, hormonal deficiencies persist in most of the patients. Therefore, follow-up should include both imaging and pituitary function assessment.

Diabetes Insipidus.

Disruption of water and electrolyte balance is frequently encountered in clinical medicine. Regulating water metabolism is critically important. Diabetes insipidus (DI) presented with excessive water loss from the kidney is a major disorder of water metabolism. To understand the molecular and cellular mechanisms and pathophysiology of DI and rationales of clinical management of DI is important for both research and clinical practice. This chapter will first review various forms of DI focusing on central diabetes insipidus (CDI) and nephrogenic diabetes insipidus (NDI ) . This is followed by a discussion of regulatory mechanisms underlying CDI and NDI , with a focus on the regulatory axis of vasopressin, vasopressin receptor 2 (V2R ) and the water channel molecule, aquaporin 2 (AQP2 ). The clinical manifestation, diagnosis and management of various forms of DI will also be discussed with highlights of some of the latest therapeutic strategies that are developed from in vitro experiments and animal studies.

Jean Camus and Gustave Roussy: pioneering French researchers on the endocrine functions of the hypothalamus.

At the beginning of the twentieth century, the hypothalamus was known merely as an anatomical region of the brain lying beneath the thalamus. An increasing number of clinicopathological reports had shown the association of diabetes insipidus and adiposogenital dystrophy (Babinski-Fröhlich's syndrome), with pituitary tumors involving the infundibulum and tuber cinereum, two structures of the basal hypothalamus. The French physicians Jean Camus (1872-1924) and Gustave Roussy (1874-1948) were the first authors to undertake systematic, controlled observations of the effects of localized injuries to the basal hypothalamus in dogs and cats by pricking the infundibulo-tuberal region (ITR) with a heated needle. Their series of surgical procedures, performed between 1913 and 1922, allowed them to claim that both permanent polyuria and adiposogenital dystrophy were symptoms caused by damage to the ITR. Their results challenged the dominant doctrine of hypopituitarism as cause of diabetes insipidus and adiposogenital dystrophy that derived from the experiments performed by Paulescu and Cushing a decade earlier. With their pioneering research, Camus and Roussy influenced the experimental work on the hypothalamus performed by Percival Bailey and Frederic Bremer at Cushing's laboratory, confirming the hypothalamic origin of these symptoms in 1921. More importantly, they provided the foundations for the physiological paradigm of Neuroendocrinology, the hypothalamus' control over the endocrine secretions of the pituitary gland, as well as over water balance and fat metabolism. This article aims to credit Camus and Roussy for their groundbreaking, decisive contributions to postulate the hypothalamus being the brain region in control of endocrine homeostasis and energy metabolism.

Adipsic diabetes insipidus in adult patients.

INTRODUCTION: Adipsic diabetes insipidus (ADI) is a very rare disorder, characterized by hypotonic polyuria due to arginine vasopressin (AVP) deficiency and failure to generate the sensation of thirst in response to hypernatraemia. As the sensation of thirst is the key homeostatic mechanism that prevents hypernatraemic dehydration in patients with untreated diabetes insipidus (DI), adipsia leads to failure to respond to aquaresis with appropriate fluid intake. This predisposes to the development of significant hypernatraemia, which is the typical biochemical manifestation of adipsic DI. METHODS: A literature search was performed to review the background, etiology, management and associated complications of this rare condition. RESULTS: ADI has been reported to occur in association with clipping of an anterior communicating artery aneurysm following subarachnoid haemorrhage, major hypothalamic surgery, traumatic brain injury and toluene exposure among other conditions. Management is very difficult and patients are prone to marked changes in plasma sodium concentration, in particular to the development of severe hypernatraemia. Associated hypothalamic disorders, such as severe obesity, sleep apnoea and thermoregulatory disorders are often observed in patients with ADI. CONCLUSION: The management of ADI is challenging and is associated with significant morbidity and mortality. Prognosis is variable; hypothalamic complications lead to early death in some patients, but recent reports highlight the possibility of recovery of thirst.

Amyloid-like aggregation of provasopressin in diabetes insipidus and secretory granule sorting.

BACKGROUND: Aggregation of peptide hormone precursors in the trans-Golgi network is an essential process in the biogenesis of secretory granules in endocrine cells. It has recently been proposed that this aggregation corresponds to the formation of functional amyloids. Our previous finding that dominant mutations in provasopressin, which cause cell degeneration and diabetes insipidus, prevent native folding and produce fibrillar aggregates in the endoplasmic reticulum (ER) might thus reflect mislocalized amyloid formation by sequences that evolved to mediate granule sorting. RESULTS: Here we identified two sequences responsible for fibrillar aggregation of mutant precursors in the ER: the N-terminal vasopressin nonapeptide and the C-terminal glycopeptide. To test their role in granule sorting, the glycopeptide was deleted and/or vasopressin mutated to inactivate ER aggregation while still permitting precursor folding and ER exit. These mutations strongly reduced sorting into granules and regulated secretion in endocrine AtT20 cells. CONCLUSION: The same sequences - vasopressin and the glycopeptide - mediate physiological aggregation of the wild-type hormone precursor into secretory granules and the pathological fibrillar aggregation of disease mutants in the ER. These findings support the amyloid hypothesis for secretory granule biogenesis.

Actualités autour de la prise en charge des diabètes insipides centraux: Management of central diabetes insipidus in 2016.

Diabetes insipidus is a syndrome that associates both hypotonic polyuria and polydipsia, due to insufficient or ineffective arginine vasopressin (AVP) synthesis, or to AVP resistance. The diagnosis between central/renal origin, or an abnormal thirst regulation (primary polydipsia) is required to organize an adapted management. Because water deprivation tests are not reliable, it's often based on medical history, response to treatment and MRI. Copeptin is an AVP precursor which could be very helpful for the diagnosis. Its basal dosage may identify nephrogenic DI whereas osmotic stimulated dosage would discriminate central DI and primary polydipsia. Central DI is quite frequent after pituitary surgeries or traumatic brain injuries, and often transient. In case of early diagnosis and familial history of DI, a mutation of AVP gene is suspected, most of the time autosomal dominant. MRI is required to identify the other causes, i.e. tumors and inflammatory diseases (sarcoidosis, histiocytosis, hypophysitis). An advanced evaluation is required before idiopathic DI be retained, especially if a thickening of pituitary stalk is observed. The treatment of central DI is mainly based on lyophilisate of desmopressin administration.

Disorders of water metabolism: diabetes insipidus and the syndrome of inappropriate antidiuretic hormone secretion.

Disorders of body fluids are among the most commonly encountered problems in the practice of clinical medicine. This is in large part because many different disease states can potentially disrupt the finely balanced mechanisms that control the intake and output of water and solute. It therefore behooves clinicians treating such patients to have a good understanding of the pathophysiology, the differential diagnosis and the management of these disorders. Since body water is the primary determinant of the osmolality of the extracellular fluid (ECF), disorders of body water homeostasis can be divided into hypoosmolar disorders, in which there is an excess of body water relative to body solute, and hyperosmolar disorders, in which there is a deficiency of body water relative to body solute. The classical hyperosmolar disorder is diabetes insipidus (DI), and the classical hypoosmolar disorder is the syndrome of inappropriate antidiuretic hormone secretion (SIADH). This chapter first reviews the regulatory mechanisms underlying water and sodium metabolism, the two major determinants of body fluid homeostasis. The major disorders of water metabolism causing hyperosmolality and hypoosmolality, DI and SIADH, are then discussed in detail, including the pathogenesis, differential diagnosis and treatment of these disorders.

Rathke's cleft cyst.

Rathke's cleft cysts are benign sellar and suprasellar lesions arising from epithelial remnants of Rathke's pouch with a peak incidence at 30-50 years of age. The majority are between 10 and 20mm in diameter and contain mucoid or gelatinous material encapsulated in a thin cyst wall of simple or pseudostratified cuboidal or columnar epithelium. Symptomatic cases are rare, but incidental lesions are found in 11% of unselected postmortem cases. The pathogenesis of these lesions is uncertain, but they may occasionally share histopathologic features with (papillary) craniopharyngiomas. The most common presenting symptoms include headaches, visual disturbance, and pituitary hormone abnormalities. MRI reveals well-demarcated homogenous lesions with variable intensity that is highly dependent on cyst contents, which can range from clear, CSF-like fluid to thick, mucoid material. Treatment is almost invariably surgical with the aim of draining the cyst contents and removing the surrounding capsule. The recurrence rate is uncertain due to a lack of studies with long follow-up periods, but risk factors associated with increased likelihood of recurrence include cyst size, presence of squamous metaplasia of the cyst wall, incomplete resection or intraoperative CSF leak, and the need for an abdominal fat graft or sellar packing.