Dynamic endocrine testing and magnetic resonance imaging in the long-term follow-up of childhood langerhans cell histiocytosis

Paediatric Langerhans Cell Histiocytosis Disease: Long-Term Sequelae in the Hypothalamic Endocrine System

Langerhans cell histiocytosis (LCH) is a disorder of the mononuclear phagocyte system that can affect almost any organ and system. The most common central nervous system (CNS) manifestation in LCH is the infiltration of the hypothalamic-pituitary region leading to destruction and neurodegeneration of CNS tissue. The latter causes the most frequent endocrinological manifestation, that is, central diabetes insipidus (CDI), and less often anterior pituitary hormone deficiency (APD). The reported incidence of CDI is estimated between 11.5 and 24% and is considered a risk factor for neurodegenerative disease and APD. Three risk factors for development of CDI are recognized in the majority of the studies: (1) multisystem disease, (2) the occurrence of reactivations or active disease for a prolonged period, and (3) the presence of craniofacial bone lesions. Since CDI may occur as the first manifestation of LCH, differential diagnosis of malignant diseases like germ cell tumours must be made. APD is almost always associated with CDI and can appear several years after the diagnosis of CDI. Growth hormone is the most commonly affected anterior pituitary hormone. Despite significant advances in the knowledge of LCH in recent years, little progress has been made in preventing long-term sequelae such as those affecting the hypothalamic-pituitary system.

Endocrine Outcomes In Central Diabetes Insipidus: the Predictive Value of Neuroimaging "Mismatch Pattern"

CONTEXT

The etiology of central diabetes insipidus (CDI) in children is often unknown. Clinical and radiological features at disease onset do not allow discrimination between idiopathic forms and other conditions or to predict anterior pituitary dysfunction.

OBJECTIVE

To evaluate the evolution of pituitary stalk (PS) thickening and the pattern of contrast-enhancement in relation with etiological diagnosis and pituitary function.

METHODS

We enrolled 39 children with CDI, 29 idiopathic and 10 with Langerhans cell histiocytosis (LCH). Brain magnetic resonance images taken at admission and during follow-up (332 studies) were examined, focusing on PS thickness, contrast-enhancement pattern, and pituitary gland size; T2-DRIVE and postcontrast T1-weighted images were analyzed.

RESULTS

Seventeen of 29 patients (58.6%) with idiopathic CDI displayed "mismatch pattern," consisting in a discrepancy between PS thickness in T2-DRIVE and postcontrast T1-weighted images; neuroimaging findings became stable after its appearance, while "mismatch" appeared in LCH patients after chemotherapy. Patients with larger PS displayed mismatch more frequently (P = 0.003); in these patients, reduction of proximal and middle PS size was documented over time (P = 0.045 and P = 0.006). The pituitary gland was smaller in patients with mismatch (P < 0.0001). Patients with mismatch presented more frequently with at least one pituitary hormone defect, more often growth hormone deficiency (P = 0.033).

CONCLUSIONS

The PS mismatch pattern characterizes patients with CDI, reduced pituitary gland size, and anterior pituitary dysfunction. The association of mismatch pattern with specific underlying conditions needs further investigation. As patients with mismatch show stabilization of PS size, we assume a prognostic role of this peculiar pattern, which could be used to lead follow-up.

Central diabetes insipidus in children: Diagnosis and management

Central diabetes insipidus (CDI) is a complex disorder in which large volumes of dilute urine are excreted due to arginine-vasopressin deficiency, and it is caused by a variety of conditions (genetic, congenital, inflammatory, neoplastic, traumatic) that arise mainly from the hypothalamus. The differential diagnosis between diseases presenting with polyuria and polydipsia is challenging and requires a detailed medical history, physical examination, biochemical approach, imaging studies and, in some cases, histological confirmation. Magnetic resonance imaging is the gold standard method for evaluating the sellar-suprasellar region in CDI. Pituitary stalk size at presentation is variable and can change over time, depending on the underlying condition, and other brain areas or other organs - in specific diseases - may become involved during follow up. An early diagnosis and treatment are preferable in order to avoid central nervous system damage and the risk of dissemination of germ cell tumor, or progression of Langerhans Cell Histiocytosis, and in order to start treatment of additional pituitary defects without further delay. This review focuses on current diagnostic work-up and on the role of neuroimaging in the differential diagnosis of CDI in children and adolescents. It provides an update on the best approach for diagnosis - including novel biochemical markers such as copeptin - treatment and follow up of children and adolescents with CDI; it also describes the best approach to challenging situations such as post-surgical patients, adipsic patients, patients undergoing chemotherapy and/or in critical care.

Role of MRI T2-DRIVE in the assessment of pituitary stalk abnormalities without gadolinium in pituitary diseases

OBJECTIVE

To investigate the role of T2-DRIVE MRI sequence in the accurate measurement of pituitary stalk (PS) size and the identification of PS abnormalities in patients with hypothalamic-pituitary disorders without the use of gadolinium.

DESIGN

This was a retrospective study conducted on 242 patients who underwent MRI due to pituitary dysfunction between 2006 and 2015. Among 135 eligible patients, 102 showed eutopic posterior pituitary (PP) gland and 33 showed 'ectopic' PP (EPP).

METHODS

Two readers independently measured the size of PS in patients with eutopic PP at the proximal, midpoint and distal levels on pre- and post-contrast T1-weighted as well as T2-DRIVE images; PS visibility was assessed on pre-contrast T1 and T2-DRIVE sequences in those with EPP. The length, height, width and volume of the anterior pituitary (AP), PP height and length and PP area were analyzed.

RESULTS

Significant agreement between the two readers was obtained for T2-DRIVE PS measurements in patients with 'eutopic' PP; a significant difference was demonstrated between the intraclass correlation coefficient calculated on the T2-DRIVE and the T1-pre- and post-contrast sequences. The percentage of PS identified by T2-DRIVE in EPP patients was 72.7% compared to 30.3% of T1 pre-contrast sequences. A significant association was found between the visibility of PS on T2-DRIVE and the height of AP.

CONCLUSION

T2-DRIVE sequence is extremely precise and reliable for the evaluation of PS size and the recognition of PS abnormalities; the use of gadolinium-based contrast media does not add significant information and may thus be avoided.

Classical and non-classical causes of GH deficiency in the paediatric age

Growth hormone deficiency (GHD) may result from a failure of hypothalamic GHRH production or release, from congenital disorders of pituitary development, or from central nervous system insults including tumors, surgery, trauma, radiation or infiltration from inflammatory diseases. Idiopathic, isolated GHD is the most common sporadic form of hypopituitarism. GHD may also occur in combination with other pituitary hormone deficiencies, and is often referred to as hypopituitarism, combined pituitary hormone deficiency (CPHD), multiple pituitary hormone deficiency (MPHD) or panhypopituitarism. Children without any identifiable cause of their GHD are commonly labeled as having idiopathic hypopituitarism. MRI imaging is the technique of choice in the diagnosis of children with hypopituitarism. Marked differences in MRI pituitary gland morphology suggest different etiologies of GHD and different prognoses. Pituitary stalk agenesis and ectopic posterior pituitary (EPP) are specific markers of permanent GHD, and patients with these MRI findings show a different clinical and endocrine outcome compared to those with normal pituitary anatomy or hypoplastic pituitary alone. Furthermore, the classic triad of ectopic posterior pituitary gland, pituitary stalk hypoplasia/agenesis, and anterior pituitary gland hypoplasia is generally associated with permanent GHD. T2 DRIVE images aid in the identification of pituitary stalk without the use of contrast medium administration. Future developments in imaging techniques will undoubtedly reveal additional insights. Mutations in a number of genes encoding transcription factors - such as HESX1, SOX2, SOX3, LHX3, LHX4, PROP1, POU1F1, PITX, GLI3, GLI2, OTX2, ARNT2, IGSF1, FGF8, FGFR1, PROKR2, PROK2, CHD7, WDR11, NFKB2, PAX6, TCF7L1, IFT72, GPR161 and CDON - have been associated with pituitary dysfunction and abnormal pituitary gland development; the correlation of genetic mutations to endocrine and MRI phenotypes has improved our knowledge of pituitary development and management of patients with hypopituitarism, both in terms of possible genetic counseling, and of early diagnosis of evolving anterior pituitary hormone deficiencies.

Pituitary stalk thickening on MRI: when is the best time to re-scan and how long should we continue re-scanning for?

Magnetic resonance imaging (MRI) has proved to be an essential tool in the assessment of pituitary stalk lesions including lymphocytic infundibulo-hypophysitis, Langerhans cell histiocytosis (LCH), germ cell tumours, nongerminomatous germ cell tumours, pituicytomas and other tumours, metastases from lymphoma or breast cancer, Wegener's hypophysitis, neurosarcoidosis and inflammatory infiltrations by infectious diseases. The diagnosis of lesions determining pituitary stalk thickness is challenging, and the identification of the underlying condition may require a long-term follow-up. Thus, clinicians should readily recognize that, when the diagnosis of central diabetes insipidus has been established, specific MRI sequences should be used in the assessment of the hypothalamic-pituitary region, and whole-brain evaluation is recommended. For clinical practice, a timely diagnosis is advisable to avoid central nervous system damage, pituitary defects and the risk of dissemination of germ cell tumours or organ involvement by LCH. Proper aetiological diagnosis can be achieved via a series of steps that start with careful observation of several neuroimaging predictors and endocrine dysfunction and then progress to more sophisticated and advanced imaging techniques.

Management of diabetes insipidus and adipsia in the child

Central diabetes insipidus (CDI) is a complex and heterogeneous clinical syndrome affecting the hypothalamic-neurohypophyseal network and water balance. A recent national surveillance in Denmark showed a prevalence rate of twenty-three CDI patients per 100,000 inhabitants in five years. The differential diagnosis between several presenting conditions with polyuria and polydipsia is puzzling, and the etiological diagnosis of CDI remains a challenge before the identification of an underlying cause. For clinical practice, a timely diagnosis for initiating specific treatment in order to avoid central nervous system damage, additional pituitary defects and the risk of dissemination of germ cell tumor is advisable. Proper etiological diagnosis can be achieved via a series of steps that start with careful clinical observation of several signs and endocrine symptoms and then progress to more sophisticated imaging tools. This review summarizes the best practice and approach for the diagnosis and treatment of patients with CDI.

Blood spotlight on Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a rare disease affecting people of any age, with widely variable clinical manifestations and different outcomes. The precise chain of events driving lesional granuloma formation has remained elusive for many years. There is evidence for inherited predisposition to and derangement of apoptosis and inflammation in lesional dendritic cells. Recently somatic BRAF(V600E) mutation in myeloid precursor dendritic cells was associated with the more aggressive form of the disease, although the same mutation in a more differentiated dendritic cell might drive a less aggressive disease. Whether this picture convincingly put LCH in the field of myeloid neoplasm remains to be determined. Altogether, these findings suggest that future therapeutic strategy might incorporate a screening of this genetic mutation for high-risk patients potentially suitable for target therapy.

Predictors of neoplastic disease in children with isolated pituitary stalk thickening

BACKGROUND

The significance of pituitary stalk thickening (PST) on magnetic resonance imaging (MRI) is often unclear. We evaluated presenting symptoms, MRI findings, clinical course, and outcome predictors of patients with PST.

PROCEDURE

We used a computerized search of the medical record from 1995 to 2008 to identify patients with PST without pituitary mass on MRI. Baseline and follow-up MRIs were reviewed in a blinded fashion. Relevant clinical data were abstracted.

RESULTS

69 patients with reported PST and adequate imaging for review were identified; 42 met study criteria. Median age at first abnormal MRI was 13.6 years (range: 0.8-19.7); 43% were male. Median follow-up was 3.4 years (range 0-12.8). Patients with diabetes insipidus (DI) were significantly more likely to have a neoplastic process than those without (P = 0.0008). Of 16 patients with DI, 8 (50%) had a neoplastic process, including germ cell tumor (n = 4), Langerhans cell histiocytosis (n = 3), and lymphoma (n = 1). Among patients with DI, 7 (44%) also developed anterior pituitary hormone dysfunction (APD), either at presentation or on pre-biopsy follow-up, including 6/8 patients with stalk neoplasm and only 1/8 patients with non-neoplastic PST (P = 0.04). Twenty-six patients presented without DI; none was found to have neoplasm of the stalk except one patient with craniopharyngioma. Progression of PST on follow-up imaging was significantly associated with a subsequent neoplastic diagnosis (P = 0.04).

CONCLUSION

Patients with PST without DI are unlikely to have a neoplastic process. Among patients with DI, APD or progressive stalk increase over time are predictive of neoplasia.

Primary hypothyroidism, precocious puberty and hypothalamic obesity in Langerhans cell histiocytosis

A 5 year old girl presented with central diabetes insipidus and primary hypothyroidism. No clinical or radiological evidence of Langerhans cell histiocytosis (LCH) was present. Absent posterior pituitary bright spot was seen in magnetic resonance imaging of the brain. She subsequently developed severe headache, massive obesity, accelerated growth and thelarche. A repeat MRI of the brain revealed hypothalamic tumor. Hormonal investigations revealed, paradoxically, undetectable growth hormone on a clonidine stimulation test. Langerhans cell histiocytosis was proved on electron microscopy of the thyroid tissue. There needs to be a high degree of suspicion for LCH as an etiology of primary hypothyroidism, especially in the presence of diabetes insipidus. Precocious puberty, accelerated growth despite growth hormone deficiency, hypothalamic obesity may occur in pediatric LCH. CNS lesions may have an evolving course, thus repeat neuroimaging is important.

Autoimmune hypophysitis: expanding the differential diagnosis to CTLA-4 blockade

Autoimmune hypophysitis is an increasingly recognized disorder that enters in the differential diagnosis of nonfunctioning pituitary masses. The differential diagnosis of these conditions is challenging because of similar clinical presentations and radiological signs. This review describes the essential features of hypophysitis and the other nonfunctioning pituitary masses. It also emphasizes a recently described feature of hypophysitis: its appearance with unexpectedly high frequency in patients receiving treatments that abrogate the function of cytotoxic T lymphocyte antigen 4.

Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a poorly understood proliferative disease, with different patterns of clinical presentation. Currently it is classified according to the number and type of system involved and the degree of organ dysfunction. The aetiology of the disease remains uncertain, and in some cases the disease is polyclonal, suggesting a reactive condition. Many cytokines have been implicated in the pathogenesis of LCH. Different therapeutic approaches can be considered depending on the affected organ, including surgery, radiotherapy and chemotherapy. Long-term organ dysfunction may remain, despite disease control and/or eradication, making indefinite supportive treatment mandatory. Here we present a literature review on all of the aspects of the disease, treatment approaches and existing protocols, and finally an adult clinical case.

Langerhans cell histiocytosis: update for the pediatrician

PURPOSE OF REVIEW

Langerhans cell histiocytosis is the commonest of the histiocytic disorders. Owing to the relative rarity of the condition, it remains a disease in which the diagnosis is often delayed or missed and in which many questions remain unanswered, ranging from etiology and pathogenesis to therapy. The management is often frustrating for care-givers and parents/patients. The purpose of the review is therefore to raise awareness of the disease and to highlight the clinical findings that should make the pediatrician or primary care-giver suspect the diagnosis, as well as current thinking regarding management of the various and diverse manifestations of this disease.

RECENT FINDINGS

We discuss new and interesting insights into the biology of Langerhans cell histiocytosis that raise the possibility of future targeted therapy. Important points in the diagnosis, investigation and management of the various forms of the disease are also discussed.

SUMMARY

We present a review of childhood Langerhans cell histiocytosis, highlighting new insights into pathogenesis and management of the various forms of this complex disease.

Isolated Langerhans cell histiocytosis in an adult with central diabetes insipidus: case report and review of literature

OBJECTIVE

To report a case of ectopic adrenocorticotropic hormone (ACTH) syndrome (EAS) in a patient with two distinct neuroendocrine tumors and to highlight the difficulties of establishing the differential diagnosis of EAS.

METHODS

We describe the clinical presentation of the current case, discuss its management, and report the results of molecular studies undertaken to determine whether the two tumors had a common origin.

RESULTS

A 52-year-old woman presented with obvious features of Cushing's syndrome. Findings on hormonal evaluation were consistent with EAS. Pituitary magnetic resonance imaging revealed normal findings. Computed tomographic imaging disclosed two masses, one in the lung and one in the pancreas. Somatostatin receptor scintigraphy showed uptake only in the pancreatic mass, which was surgically removed. It was a well-differentiated neuroendocrine tumor, with negative immunostaining for ACTH. Hypercortisolemia did not resolve after removal of the pancreatic tumor. The lung mass was subsequently excised, and pathology examination showed a carcinoid tumor with immunostaining for ACTH. Thereafter, plasma ACTH became immeasurable. The two tumors had similar patterns of X-chromosome inactivation; thus, whether they arose independently could be neither confirmed nor excluded.

CONCLUSION

This case demonstrates that, in the presence of more than one neuroendocrine tumor, somatostatin receptor scintigraphy may misguide the decision regarding the appropriate surgical course in patients with EAS, and it highlights the need for accurate studies to determine the source of ACTH in patients with EAS.

[Impact of systemic disease on the pituitary gland]

Systemic diseases located in hypothalamo-pituitary region can slowly induce pituitary deficiency, diabetes insipidus and morphological abnormalities. The aim of this study is to review recent clinical data about diagnosis of these rare diseases, with a focus on granulomatous diseases: histiocytosis and sarcoidosis. Recent clinical studies on histiocytosis have improved our knowledge about endocrine expression of the disease in children and in adults as well. Diabetes insipidus is the most frequent condition, described mainly in children. GH deficiency is the most frequent pituitary deficit in children and adult patients. During neurosarcoidosis, diabetes insipidus is the most frequent condition and gonadotropic deficiency is the most frequent deficit but GH has not been systematically studied. MRI allows visualisation of some lesions and is very useful to follow the disease course. Diagnosis of these diseases is made by clinical evaluation of all the sites and by pathological analysis of biopsies of peripheral lesions. While pituitary hormone replacement therapy does not seem to raise specific problems in these diseases, etiological treatments are not yet available and indications for antimitotic or immunomodulatory treatment are sometimes discussed.

Spontaneous gonadotrophin deficiency recovery in an adult patient with Langerhans cell histiocytosis (LCH)

Langerhans cell histocytosis (LCH) is a rare disease which exhibits a particular predilection for pituitary involvement leading to diabetes insipidus (DI) and other anterior pituitary hormonal deficiencies that are usually permanent and unresponsive to treatment. We report a 35 year old woman with a 10 year history of multisystemic LCH who developed DI, mild hyperprolactinemia, gonadotrophin and partial growth hormone deficiency following a normal delivery that was accompanied with infundibular thickening on pituitary magnetic resonance imaging (MRI). Following several courses of glucocorticoid administration, that were not associated with any substantial improvement, the patient was started on estrogen replacement therapy and cabergoline. After a three year period free of further relapses she developed irregular uterine bleeding. Following estrogen and cabergoline discontinuation she resumed normal menstruation while a repeated MRI of the pituitary showed an almost normal infundibulum. Endocrine investigation revealed normal gonadotrophin axis and prolactin levels, while the patient continues to menstruate, every 30-40 days, ten months after the resumption of her menstrual cycle. This case demonstrates for the first time that LCH induced pituitary deficiencies can run a variable clinical course and even spontaneously recover.

Hypopituitarism in langerhans cell histiocytosis: seven cases and literature review

Central nervous system (CNS) involvement and, in particular, hypothalamic-pituitary involvement are well described features of Langerhans cell histiocytosis (LCH). The actual incidence of CNS-LCH disease is unknown and the natural history is poorly understood. Diabetes insipidus (DI) is reported to be the most common and well described manifestation of hypothalamic-pituitary involvement (up to 50%). Anterior pituitary dysfunction has been reported in up to 20% of patients with LCH, and occurs almost exclusively concurrently with DI. In the current paper we describe our experience with 7 patients (6 females and 1 male) in whom hypothalamicpituitary involvement was a major feature of LCH. Diagnosis was made in 4 patients during childhood or adolescence, and 3 patients were over 18 years old at the time of diagnosis. Our series exemplifies the wide spectrum of LCH-induced hypopituitarism, and demonstrates some unique features, including a higher incidence of CRH/ACTH deficiency compared to other reports (4/7 patients), and massive obesity in 2 of our patients. Endocrine function was not improved in any of our patients following medical treatment of LCH with chemotherapy and glucocorticoids. We conclude that pituitary-hypothalamic dysfunction is a common feature of LCH, and therefore all LCH patients should undergo a thorough endocrine evaluation periodically.

Reversible hypogonadotrophic hypogonadism in sexually infantile male thalassaemic patients with transfusional iron overload

OBJECTIVE

To determine the severity and reversibility of the lesion in the hypothalamic-pituitary (H-P) axis of male transfusion-dependent thalassaemic patients with failed puberty (FP).

DESIGN AND SUBJECTS

The hypothalamic-pituitary axes of 20 male thalassaemic patients (study group) were compared with two male subjects with idiopathic hypogonadotrophic hypogonadism (IHH) and five prepubertal healthy siblings (control group). GnRH-gonadotrophin insufficiency was characterized by nocturnal 12 h ultradian gonadotrophin profiles followed by a 100 microg GnRH bolus test (GBT) 4-6 times at 6 monthly intervals. Thalassaemic and IHH patients were then subjected to pulsatile subcutaneous GnRH infusions every 120 minutes for 3 months. Ultradian gonadotrophin profiles and GBT were repeated after 6 weeks of GnRH infusion and again at 3 months following infusion.

MEASUREMENTS

FSH and LH were measured by radio-immunoassay. Ferritin was assayed by an immunoradiometric method.

RESULTS

Patients with IHH who were apulsatile prior to infusion, developed normal gonadotrophin pulses with marked increment in their gonadotrophin responses to the GBT after 3 months of GnRH infusion. In contrast, the thalassaemic patients with apulsatile failed puberty (AFP) remained apulsatile (nonresponders) and had no increment in their gonadotrophin responses to the GBT after GnRH infusion. All patients with pulsatile failed puberty (PFP) had abnormal gonadotrophin pulses prior to GnRH infusion. Their pulse defects were either totally or partially corrected (responders) following infusion. The serum ferritin levels (9500 +/- 500 microg/l vs. 5966.67 +/- 1139 microg/l; P < 0.01) and percentage of organ dysfunction (87% vs. 17%; P < 0.01) were higher in the nonresponders than the responders.

CONCLUSIONS

This study shows that thalassaemic patients with severe organ damage and iron overload are likely to be apulsatile with irreversible damage to their hypothalamo-pituitary axis, while those with less severe iron overload are likely to have potentially reversible hypogonadotrophic hypogonadism (HH). Our results also suggest that gonadotrophin pulse parameters, rather than the gonadotrophin response to a GnRH bolus following prolonged pulsatile GnRH infusion, may be more useful in discriminating reversible from irreversible hypogonadotrophic hypogonadism.