Genetic overlap in Kallmann syndrome, combined pituitary hormone deficiency, and septo-optic dysplasia

CONTEXT

Kallmann syndrome (KS), combined pituitary hormone deficiency (CPHD), and septo-optic dysplasia (SOD) all result from development defects of the anterior midline in the human forebrain.

OBJECTIVE

The objective of the study was to investigate whether KS, CPHD, and SOD have shared genetic origins.

DESIGN AND PARTICIPANTS

A total of 103 patients with either CPHD (n = 35) or SOD (n = 68) were investigated for mutations in genes implicated in the etiology of KS (FGFR1, FGF8, PROKR2, PROK2, and KAL1). Consequences of identified FGFR1, FGF8, and PROKR2 mutations were investigated in vitro.

RESULTS

Three patients with SOD had heterozygous mutations in FGFR1; these were either shown to alter receptor signaling (p.S450F, p.P483S) or predicted to affect splicing (c.336C>T, p.T112T). One patient had a synonymous change in FGF8 (c.216G>A, p.T72T) that was shown to affect splicing and ligand signaling activity. Four patients with CPHD/SOD were found to harbor heterozygous rare loss-of-function variants in PROKR2 (p.R85G, p.R85H, p.R268C).

CONCLUSIONS

Mutations in FGFR1/FGF8/PROKR2 contributed to 7.8% of our patients with CPHD/SOD. These data suggest a significant genetic overlap between conditions affecting the development of anterior midline in the human forebrain.

Pituicytomas: radiological findings, clinical behavior and surgical management

BACKGROUND

Pituicytomas are rare low-grade glial neoplasms originating in the neurohypophysis or infundibulum that appear as solid, noninfiltrative masses occupying the sella turcica, the suprasellar space or both. Due to their high tendency to bleed and the possible firmness and adhesion to surrounding structures, preoperative diagnosis of pituicytoma is a goal for the surgeon, but it is actually a challenge because of the absence of distinctive clinical or neuroradiological findings.

METHODS

We report the new cases of three patients who underwent transsphenoidal surgery for suspected pituitary adenomas, which were determined to be pituicytomas at histological and immunohistochemical analysis. We also review previously reported cases of pituicytoma in the literature.

RESULTS

To date, 51 cases of pituicytoma have been reported in addition to our own cases. The natural history and clinical characteristics of this rare tumor are outlined.

CONCLUSIONS

Macroscopic aspects are variable, and final diagnosis is made from the typical histological and immunohistochemical pattern. The therapy of choice is gross total surgical resection since subtotal removal can lead to local regrowth, but the time to recurrence is unpredictable and highly variable. The role of adjuvant therapy is currently undefined.

Posterior pituitary (PP) evaluation in patients with anterior pituitary defect associated with ectopic PP and septo-optic dysplasia

OBJECTIVE

Controversies exist about posterior pituitary (PP) function in subjects with ectopic PP (EPP) and with cerebral midline defects and/or their co-occurrence. We investigate water and electrolyte disturbances in patients at risk for PP dysfunction.

DESIGN

The study was conducted in a single Pediatric Endocrinology Research Unit.

METHODS

Forty-two subjects with childhood-onset GH deficiency were subdivided into five groups: normal magnetic resonance imaging (n=8, group 1); EPP (n=15, group 2); septo-optic dysplasia (SOD) with normal PP (n=4, group 3); EPP and SOD without (n=7, group 4), and with additional midline brain abnormalities (n=8, group 5). At a mean age of 16.0±1.1 years, they underwent a 120 min i.v. infusion with hypertonic 5% saline and evaluation of plasma osmolality (Posm), arginine vasopressin (AVP), thirst score (in groups 1 and 2), and urinary osmolality were performed.

RESULTS

Mean Posm and AVP significantly increased from baseline scores (284.7±4.9 mosm/kg and 0.6±0.2 pmol/l) to 120 min after saline infusion (300.5±8.0 mosm/kg and 10.3±3.3 pmol/l, P<0.0001). Group 5 showed higher mean Posm and lower mean AVP at all time points (P<0.0001). Mean thirst score did not show a significantly different trend between the groups 1 and 2. Urine osmolality was above 750 mosm/kg in all but seven patients after osmotic challenge.

CONCLUSIONS

Patients with midline brain abnormalities and EPP have defective osmoregulated AVP. Patients with EPP and congenital hypopituitarism have normal PP function.

[Management and microsurgical treatment of infundibular dilatations of the posterior communicating artery. Series of nine cases and review of the literature]

INTRODUCTION

The infundibular dilatation (ID) of the posterior communicating (PCom) artery is defined as the conic, triangular or infundibular shaped, less than 3mm wide, origin of the PCom artery from the internal carotid artery. The purpose of this paper is to present the personal experience in the microsurgical management of the ID, to review the literature and to propose some algorithms to improve its clinical and microsurgical management.

MATERIAL AND METHODS

Nine cases of ID have been operated on through a pterional approach. In four patients with subarachnoid hemorrhage (SAH) the ID was considered as the potential source of the bleeding; in four cases the ID was treated after a SAH due to the rupture of an aneurysm; finally, an ID was treated in patient with diagnosis of pseudoxantoma elasticum.

RESULTS

In eight cases the ID was clipped and the Pcom artery subsequently occluded and in the remaining case the ID was associated with a fetal PComA and the ID was reinforced. There were no complications excepting a transitory third cranial nerve paresis. The Glasgow Outcome Scale was 5 in all cases at discharge and one year later.

CONCLUSIONS

The true significance of the ID remains unknown, but in some instances it is necessary to consider its management: 1. In patients with ruptured aneurysms submitted to microsurgical clipping and with an ipsilateral ID, the lesion must be explored and treated; 2. In patients with ruptured aneurysms treated with endovascular procedures or harbouring an ID contralateral to a microsurgically treated aneurysm, the microsurgical indication will be done after considering all risk factors; 3. In patients with SAH and an ID as the only potential source of the bleeding there would be an indication for microsurgical exploration; 4. The incidental finding of an ID should be indication for observation in absence of major risk factors.

Novel heterozygous nonsense GLI2 mutations in patients with hypopituitarism and ectopic posterior pituitary lobe without holoprosencephaly

CONTEXT

GLI2 is a transcription factor downstream in Sonic Hedgehog signaling, acting early in ventral forebrain and pituitary development. GLI2 mutations were reported in patients with holoprosencephaly (HPE) and pituitary abnormalities.

OBJECTIVE

The aim was to report three novel frameshift/nonsense GLI2 mutations and the phenotypic variability in the three families.

SETTING

The study was conducted at a university hospital.

PATIENTS AND METHODS

The GLI2 coding region of patients with isolated GH deficiency (IGHD) or combined pituitary hormone deficiency was amplified by PCR using intronic primers and sequenced.

RESULTS

Three novel heterozygous GLI2 mutations were identified: c.2362_2368del p.L788fsX794 (family 1), c.2081_2084del p.L694fsX722 (family 2), and c.1138 G>T p.E380X (family 3). All predict a truncated protein with loss of the C-terminal activator domain. The index case of family 1 had polydactyly, hypoglycemia, and seizures, and GH, TSH, prolactin, ACTH, LH, and FSH deficiencies. Her mother and seven relatives harboring the same mutation had polydactyly, including two uncles with IGHD and one cousin with GH, TSH, LH, and FSH deficiencies. In family 2, a boy had cryptorchidism, cleft lip and palate, and GH deficiency. In family 3, a girl had hypoglycemia, seizures, excessive thirst and polyuria, and GH, ACTH, TSH, and antidiuretic hormone deficiencies. Magnetic resonance imaging of four patients with GLI2 mutations and hypopituitarism showed a hypoplastic anterior pituitary and an ectopic posterior pituitary lobe without HPE.

CONCLUSION

We describe three novel heterozygous frameshift or nonsense GLI2 mutations, predicting truncated proteins lacking the activator domain, associated with IGHD or combined pituitary hormone deficiency and ectopic posterior pituitary lobe without HPE. These phenotypes support partial penetrance, variable polydactyly, midline facial defects, and pituitary hormone deficiencies, including diabetes insipidus, conferred by heterozygous frameshift or nonsense GLI2 mutations.

Rosai-Dorfman disease involving the neurohypophysis

Rosai-Dorfman disease is a rare, histiocytic proliferative disorder of unknown etiology commonly affecting lymph nodes. Extranodal lesions with or without nodal involvement also occur. We report the case of a 63 year-old woman with disseminated Rosai-Dorfman disease involving the neurohypophysis and associated with adenohypophysial PRL cell hyperplasia.

Transient polyuria related to central diabetes insipidus caused by lymphocytic infundibulo-neurohypophysitis in a patient treated for Graves' disease

A 45-year-old man was hospitalized because of weight loss, finger tremor, thirst, polydipsia and increased urinary frequency. He was diagnosed with Graves' disease (GD) and central diabetes insipidus (CDI). Magnetic resonance imaging revealed the enlarged posterior pituitary with thickened stalk. Histological examination obtained from biopsy of the pituitary revealed lymphocytic infundibulo-neurohypophysitis. He received treatment with thiamazole (MMI) for GD and desmopressin acetate (DDAVP) for CDI. However, DDAVP administration could be discontinued as GD was gradually improved. This course indicates that not only the recovered renal response to arginine-vasopressin but also the immunomodulative effects of MMI might attribute to the improvement of polyuria.

Granular cell tumour of the neurohypophysis: a rare sellar tumour with specific radiological and operative features

Symptomatic granular cell tumours of the neurohypophysis are rare sellar lesions. Preoperative prediction of the diagnosis on the basis of radiological appearance is useful as these tumours carry specific surgical difficulties. This is possible when the tumour arises from the pituitary stalk, rostral to a normal pituitary gland. This has not been emphasized previously.

Spontaneous regression of isolated neurohypophyseal langerhans cell histiocytosis with diabetes insipidus

In pediatric and adolescent patients, the most common causes for a thickened pituitary stalk with central diabetes insipidus are germ cell tumors, lymphocytic infundibuloneurohypophysitis (LIN), and Langerhans cell histiocytosis (LCH). We describe here a 13-year-old girl who had an abrupt onset of polyuria and polydipsia. Magnetic resonance imaging of the brain revealed thickening of the pituitary stalk, and loss of the physiological hyperintense signal of the posterior pituitary gland. Based on a histopathology, she was diagnosed as having LCH. Another LCH lesion was not detected. The prognoses for LCH patients with single-system and single-site are generally good so we decided on only simple observation. The lesion spontaneously regressed 3 months later, resembling a typical self-limiting course of LIN. In conclusion, the present case suggests that 1) radiological differential diagnosis between LIN and LCH is so difficult that histological confirmation is crucial for correct diagnosis, 2) some past cases of histologically-unconfirmed LIN can include LCH, 3) solitary neurohypophyseal LCH can shrink spontaneously up to near remission level.

Pituitary and stalk lesions (infundibulo-hypophysitis) associated with immunoglobulin G4-related systemic disease: an emerging clinical entity

Inflammatory lesions of the pituitary gland are rarely encountered. Recently, the concept of immunoglobulin G4 (IgG4)-related systemic disease was proposed in Japan, and more than 20 cases have been reported as possibly associated with infundibulo-hypophysitis since 2000. We herein review such case reports in the published literature and in the abstracts of scientific meetings. Almost all cases involved middle-aged to elderly men presenting with various degrees of hypopituitarism and diabetes insipidus and demonstrating a thickened pituitary stalk and/or pituitary mass. These structures shrank remarkably in response to glucocorticoid therapy, even in a lower dose range similar to that prescribed as a replacement for adrenocortical insufficiency. Some of the anterior pituitary insufficiencies were also resolved by glucocorticoid administration. The presence of IgG4-related systemic disease and an elevated serum IgG4 level before glucocorticoid therapy were the main clues to a correct diagnosis of IgG4-related infundibulo-hypophysitis. Autoimmunity is suggested but not yet established to play a role in the pathogenesis for IgG4-related systemic disease. The fact that hypertrophic pachymeningitis and para-sinusitis accompanied some cases suggested that both sellar and parasellar structures are involved in the chronic inflammation. We therefore classify this disorder not as a variant form of primary autoimmune hypophysitis but as a secondary form of infundibulo-hypophysitis associated with IgG4-related systemic disease.

[Permeability of rat neurohypophysial blood vessels for neurophysins and ferritin in acute hyperoxia]

The time course of the release of vasopressin-binding (nicotine-stimulated) and oxytocin-binding (estrogen-stimulated) neurophysins (NPs) into the rat pituitary and blood serum has been studied during the convulsive phase of hyperbaric oxygenation (HBO) and the postconvulsive period (PCP). The ultrastructure of the posterior pituitary (neurohypophysis) and the state of the blood-pituitary barrier in the caudal region of the gland have been studied with the use of ferritin as an exogenous marker of vascular permeability.

Histologic study of the human pituitary gland in acute traumatic brain injury

PURPOSE

Approximately 25% of patients with traumatic brain injury (TBI) may develop partial or complete hypopituitarism. The causative mechanisms involved in its development are not clear. To the authors' knowledge, there have been no recent morphologic studies of the pituitary following TBI.

METHODS

To characterize the resultant histologic changes, this study investigated the pituitaries of 42 patients who died following a motor vehicle accident, all from the Mayo Tissue Registry. Twelve patients died instantly at the scene of the accident (Group I) whereas 30 survived between 3 hours and 7 days (Group II). All pituitary specimens were obtained at autopsy, formalin-fixed and paraffin-embedded. Hematoxylin-eosin sections cut in horizontal or sagittal plane were examined light-microscopically.

RESULTS

No infarction was noted in the pituitary specimens from group I. In group II, 13 of 30 (43%) showed acute infarcts of varying size. The extent of infarction in group II ranged from focal to sub-total necrosis involving 90% of the adenohypophysis.

CONCLUSIONS

Underlying adenohypophysial pathology in patients dying after TBI is acute infarction. Loss of large numbers of adenohypophysial cells causes reduced secretion of adenohypophysial hormones and may contribute to post-traumatic hypopituitarism.

Ganglioglioma of the neurohypophysis

The normal infundibulum and neurohypophysis consist entirely of neuronal processes, the neuronal cell bodies of which lie within the supraoptic and paraventricular nuclei of the hypothalamus and supportive glial cells or pituicytes. The finding of neurons within the neurohypophysis is exceedingly rare, as are ganglion cell tumors at this site. In this paper, we report a ganglion cell tumor of the neurohypophysis found incidentally at autopsy. Despite chronic hypertension and the finding of some vasopressin immunoreactivity in lesional neurons, the syndrome of inappropriate antidiuretic hormone secretion (SIADH) was excluded on the basis of normal serum sodium levels. The morphologic and immunohistochemical features of the tumor are presented, cytogenetic considerations are discussed, and literature regarding neuronal lesions of the pituitary gland is reviewed.

Immunoexpression of androgen receptor in the nontumorous pituitary and in adenomas

Little information is available regarding androgen receptor immunoexpression (AR) in the normal and neoplastic human pituitary. Available experimental data links it to primarily gonadotroph cells. We undertook an immunohistochemical study of 41 autopsy-derived normal glands from patients of both sexes and all ages as well as 79 fully characterized pituitary adenomas of all types, the focus being upon AR expression in normal and neoplastic gonadotrophs. Nuclear AR immunoreactivity was noted in gonadotrophs and other normal adeno- and neurohypophysial cells. In addition to its presence in 74% of gonadotroph and 55% of null cell adenomas, lesser proportions of other adenoma types (adrenocorticotropic hormone 50%, prolactin 38%, growth hormone 33%) also exhibited AR immunoreactivity. No staining of thyroid-stimulating hormone adenomas was noted. The physiologic significance of our findings remains to be explored. The literature regarding AR expression in animal and human pituitaries is reviewed.

Remission of congenital diabetes insipidus after eight years

Septo-optic dysplasia (SOD) (De Morsier's syndrome) is a complex developmental disorder marked by variable and often incomplete formation of cranial midline structures, resulting in absence of the septum pellucidum, optic nerve hypoplasia, and hypothalamic-pituitary dysfunction. We describe a patient with SOD who manifested symptoms in the early neonatal period with severe deficiencies of multiple pituitary hormones including anti-diuretic hormone (ADH). Her congenital diabetic insipidus (DI), consequence of an anatomic defect, can be argued to be of the most severe type. Our patient resolved her severe DI 8 years after her initial presentation, suddenly requiring no further medical treatment for DI following longstanding pharmacological replacement of ADH. This is the first report of a patient with SOD with spontaneous resolution of congenital DI.

Anatomic and pathologic spectrum of pituitary infundibulum lesions

OBJECTIVE

The pathologic spectrum of pituitary infundibulum disease is diverse. We reviewed 65 infundibular lesions in 44 adult and 21 pediatric patients and summarized their imaging features and clinical presentation.

CONCLUSION

The spectrum of pathology involving the pituitary infundibulum is broad yet distinct from other pathology in the sella and parasellar region. Pituitary stalk lesions can be grouped into three categories: congenital and developmental, inflammatory and infectious, and neoplastic. Knowledge of the imaging appearance of diseases specific to adults and to children is important for accurate diagnosis and treatment.

Abnormal prion protein in the pituitary in sporadic and variant Creutzfeldt-Jakob disease

By using high-sensitivity Western blotting and immunohistochemistry, pituitary glands from patients with sporadic and variant Creutzfeldt-Jakob disease (sCJD and vCJD, respectively) were analysed for the presence of the protease-resistant form of the prion protein (PrPres). PrPres was detected in a greater proportion of vCJD pituitaries than sCJD pituitaries and was localized predominantly in the neurohypophysis. PrPres was also detected in a recurrent pituitary adenoma from an sCJD patient. Immunohistochemical analysis showed sparse positive labelling, predominantly in folliculostellate cells, in vCJD and sCJD adenohypophyses. The PrPres glycosylation pattern in the vCJD neurohypophyses showed a predominance of the unglycosylated band, which differed markedly from patterns found in all other vCJD tissues. The presence of PrPres in the pituitary of CJD patients at autopsy suggests that human growth hormone-related iatrogenic CJD may have indeed resulted from infectivity in collected pituitaries rather than necessarily from contamination of pituitary pools by adjacent brain tissue.

Contribution of magnetic resonance imaging in non-tumoral hypopituitarism in children

BACKGROUND

Magnetic resonance imaging (MRI) is of paramount importance for evaluating the hypothalamo-pituitary axis in children.

METHODS

We summarize the main points of the MRI technique, and describe the normal appearance of the hypothalamo-pituitary axis as a function of age and pubertal status. The most frequent causes of non-tumoral hypopituitarism include anterior pituitary deficiency (growth hormone deficiency may be isolated or associated with other anterior pituitary hormone deficiencies, with or without other malformations, and related to a known genetic abnormality in some cases), isolated hypogonadotropic hypogonadism and posterior pituitary deficiency with or without anterior pituitary hormone deficiency (central diabetes insipidus may be observed without tumor development).

RESULTS

We describe in detail the appearance of the adenohypophysis, the pituitary stalk and the neurohypophysis, correlations with hormone deficiencies, the abnormalities that may be associated and progression over time for each condition.

CONCLUSION

An accurate description of hypothalamo-pituitary axis abnormalities is necessary for accurate diagnosis and prognosis evaluation, with certain features suggestive of particular diseases and some prognostic data correlated with phenotype.

[Optic nerve hypoplasia associated to ectopic neurohypophysis]

Hypoplasia of the optic nerve is a rare congenital anomaly of unknown etiology that is a frequent cause of blindness in children. It can present in isolation or associated to other malformations of the central nervous system. Magnetic resonance is the technique of choice for the study of this condition; it enables both the hypoplasia of the nerve and the possible associated malformations to be demonstrated. We present a case of optic nerve hypoplasia associated to ectopic neurohypophysis.

Idiopathic central diabetes insipidus in children and young adults is commonly associated with vasopressin-cell antibodies and markers of autoimmunity

OBJECTIVES

Autoimmune targeting of hypothalamic-neurohypophyseal structures in children and young adults with posterior pituitary and anterior pituitary dysfunction, as well as pituitary stalk involvement, are not yet completely understood.

DESIGN

We aimed to (1) evaluate the presence of circulating vasopressin-cell autoantibodies (AVPc-Abs) in young patients with central diabetes insipidus (CDI), (2) detect organ-specific autoantibodies as markers of autoimmunity, and (3) define the relationship between immune markers and neuroimaging findings.

PATIENTS

Twenty patients were evaluated at a median age of 16.3 years. Twelve patients had idiopathic CDI, six had Langerhans cell histiocytosis (LCH) and two had germinoma. AVPc-Abs were evaluated in 40 healthy children. Magnetic resonance imaging (MRI) of the hypothalamic-pituitary region was performed longitudinally in all subjects.

MEASUREMENTS

Circulating arginine vasopressin (AVP), protein tyrosine phosphatase (IA2), glutamic acid decarboxylase (GAD), 21-hydroxylase (21-OH), endomysium antibodies (EMA), parietal cell (PCA), thyroid peroxidase (TPO), thyroglobulin (TG) and TSH-receptor (TSHr) autoantibodies were evaluated.

RESULTS

Circulating AVPc-Abs were found in 15 patients (75%), nine with idiopathic CDI, four with LCH and two with germinoma; the pituitary stalk was involved in most of them. Five patients with idiopathic CDI showed a persistence of AVPc-Abs during follow-up and one became positive subsequently. Serum IA2 autoantibodies were demonstrated in 14 patients (70%) and 21-OH autoantibodies in three of them.

CONCLUSION

In idiopathic CDI, circulating AVPc-Abs suggest an autoimmune involvement of the neurohypophyseal system. The identification of AVPc-Abs in subjects who could have either idiopathic CDI or LCH or germinoma, however, indicates that AVPc-Abs cannot be considered a completely reliable marker of autoimmune CDI. Thus, close clinical and MRI follow-up are needed because AVPc-Abs may mask germinoma or LCH.

Participation of the subfornical nucleus in hypothalamic-neurohypophyseal axis activation during the early phase of endotoxic shock

During the early phase of endotoxic shock the hypothalamus is activated and neurohypophyseal hormone secretion is increased. In order to study the participation of the subfornical organ (SFO) in this response we lesioned the nucleus and determined hormone secretion and c-fos expression in the paraventricular and supraoptic nuclei after administration of lipopolysaccharides (LPS) in rats. LPS significantly increased the number of cells showing Fos immunoreactivity in the paraventricular and supraoptic nuclei of the hypothalamus (p < 0.05) and also caused an increase in plasma levels of vasopressin and oxytocin (p < 0.05). SFO lesion significantly reduced LPS-induced Fos immunoreactivity (p < 0.05) and hormone secretion (p < 0.05). We conclude that the SFO participates in the activation of the hypothalamic-neurohypophyseal axis in the early phase of endotoxic shock.