Diagnóstico radiológico del síndrome de interrupción del tallo hipofisario. Neurohipófisis ectópica / Radiological Diagnosis of Pituitary Stalk Disruption Syndrome. Ectopic Neurohypophysis

Resumen: El síndrome de interrupción del tallo pituitario es una anomalía congénita que se caracteriza por la demostración neurorradiológica de un tallo pituitario ausente, interrumpido o hipoplásico, adenohipófisis aplásica/hipoplásica y neurohipófisis ectópica. Este síndrome se ha relacionado con formas severas de hipopituitarismo congénito, asociado a múltiples deficiencias de hormonas pituitarias. Los signos y los síntomas perinatales que presentan los pacientes incluyen hipoglucemia hasta en un 61%, ictericia en un 38%, micropene en un 77% y colestasis en un 19%, las convulsiones neonatales se dieron en el 75% de los niños. Durante la infancia suelen tener talla baja y disminución en la velocidad del crecimiento, así mismo pueden presentar retardo en la expresión de los caracteres sexuales secundarios (1). En nuestro caso clínico se trata de un paciente adolescente el cual tenía como manifestaciones clínicas principales, retardo en los caracteres sexuales secundarios, los hallazgos principales que se encontraron en la resonancia magnética nuclear, incluyeron ausencia del tallo hipofisario, neurohipófisis ectópica, localizada adyacente al túber cinereum y adenohipofisis hipoplásica.

Abstract: Pituitary stalk disruption syndrome is a congenital anomaly characterized by neuroradiologic demonstration of an absent, interrupted, or hypoplastic pituitary stalk, aplastic/ hypoplastic adenohypophysis, and ectopic neurohypophysis. This syndrome has been related to severe forms of congenital hypopituitarism, associated with multiple deficiencies of pitu- itary hormones. Perinatal signs and symptoms presented by patients include hypoglycemia in up to 61%, jaundice in 38%, micropenis in 77% and cholestasis in 19%, neonatal seizures occurred in 75% of children. During childhood, they tend to have short stature and a decrease in growth speed, as well as a delay in the expression of secondary sexual characteristics. In our clinical case, an adolescent patient was presented whose main clinical manifestations were delayed secondary sexual characteristics, the main findings were found in nuclear magnetic resonance, including absence of the pituitary stalk, ectopic neurohypophysis, located adjacent to the tuber cinereum and hypoplastic adenohypophys.

Morphological and immunohistochemical comparison of the pituitary gland between a tropical Paracheirodon axelrodi and a subtropical Aphyocharax anisitsi characids (Characiformes: Characidae)

Cardinal tetra Paracheirodon axelrodi and bloodfin tetra Aphyocharax anisitsi are two species of characids with high trade value as ornamental fish in South America. Although both species inhabit middle water layers, cardinal neon exhibits a tropical distribution and bloodfin tetra a subtropical one. Generally, these species are difficult to grow, so it becomes essential to know some key components of the neuroendocrine system to achieve their reproduction in captivity. Considering the importance of deepening the knowledge of the reproductive physiology through functional morphology, for the first time in this work we performed an anatomical, morphological and immunohistochemical analysis of the pituitary gland of these two species. In both species, a leptobasic type pituitary is found in the ventral zone of the hypothalamus and it is characterized by a neurohypophysis which has a well-developed pituitary stalk and a globular adenohypophysis. The pituitary components, characterized by histochemistry and immunohistochemistry, shows a distribution pattern of cells types similar to other teleost species, with only slight differences in the distribution of βFSH and βLH for P. axelrodi.(AU)

El cardenal tetra Paracheirodon axelrodi y el tetra Aphyocharax anisitsi son dos especies de carácidos con alto valor comercial como peces ornamentales en América del Sur. Aunque ambas especies habitan en las capas medias de agua, el neón cardenal exhibe una distribución tropical, mientras que el tetra cola roja una distribución subtropical. En general estas especies son difíciles de cultivar, por lo que es esencial conocer algunos componentes clave de los sistemas neuroendocrinos para lograr su reproducción en cautiverio. Considerando la importancia de profundizar en el conocimiento de la fisiología reproductiva a través de la morfología funcional, en este trabajo realizamos, por primera vez, un análisis anatómico, morfológico e inmunohistoquímico de la glándula pituitaria de estas dos especies. En ambas especies, la hipófisis, del tipo leptobásica, se encontró en la zona ventral del hipotálamo y se caracteriza por una neurohipófisis con un tallo hipofisario bien desarrollado y una adenohipófisis globular. Los componentes hipofisarios, caracterizados por la histoquímica y la inmunohistoquímica, mostraron un patrón de distribución de tipos de células similares a otras especies de teleósteos, con solo pequeñas diferencias en la distribución de βFSH y βLH para P. axelrodi.(AU)

A Case of Ectopic Neurohypophysis Presenting with Hypogonadism

Pituitary stalk interruption and ectopic neurohypophysis seen on magnetic resonance Imaging (MRI) are often associated with either isolated growth hormone (GH) deficiency or combined anterior pituitary hormone deficiency, but their pathogenesis is not clear and the clinical data regarding these anatomical defect is limited. We experienced a 23-year-old male with the absence of secondary sexual characteristics and this was accompanied with pituitary stalk dysgenesis and ectopic neurohypophysis. He received growth hormone for a year when he was 12 years old due to his short stature. Sella MRI showed no visible pituitary stalk with minimal high signal change, suggesting ectopic neurohypophysis. The combined pituitary stimulation test revealed blunted responses of growth hormone, follicle stimulating hormone and luteinizing hormone. For the hypogonadotropic hypogonadism, the patient was given testosterone intramuscularly and he gradually developed secondary sexual characteristics. We concluded that the hypogonadism and growth hormone deficiency in this patient was caused by hypopituitarism due to pituitary stalk dysgenesis and ecopic nuerohypophysis.

A Surgical Case of Lymphocytic Hypophysitis with Progressive Visual Worsening

Lymphocytic hypophysitis is a clinically rare disease, and it has been known to be an autoimmune disease which mainly affects pregnant women at the end of gestation or right after delivery. The authors experienced a case of lymphocytic hypophysitis in a 29-year-old pregnant woman with rapid progressing visual disturbance. Sella MRI showed a mass-like lesion of hypophysis and hypertrophy of pituitary stalk with evidences of hypopituitarism. Cesarean section was done and then TSA was performed. The pathologic diagnosis was lymphocytic hypophysitis. After TSA, visual acuity was improved and visual field defect was recovered. She was given thyroid hormone replacement therapy because of transient partial hypopituitarism for 6 months after surgery. One must consider the probability of lymphocytic hypophysitis, if there are alteration of visual acuity and visual field defect which aggravate rapidly during pregnancy due to mass effect, decreased serum hormonal levels shown in hypopituitarism and sella MRI findings of hypertrophy of pituitary stalk and enlargement of pituitary gland.

Delayed Puberty due to Pituitary Stalk Dysgenesis and Ectopic Neurohypophysis

Hypopituitarism is not a common cause of delayed puberty. A 22 year old man was referred to our clinic because of the absence of the development of secondary sexual characteristics. The patient had no complaints of physical discomfort. Random serum testosterone and luteinizing hormone level were obtained and found to be low. The combined pituitary function stimulation test revealed a partial hypopituitarism. A pituitary magnetic resonance imaging (MRI) was obtained and showed decreased pituitary stalk enhancement and ectopic neurohypophysis. Therefore, we conclude that the delayed puberty was a result of hypopituitarism due to pituitary stalk dysgenesis and ectopic neurohypophysis. The patient was started on hormone replacement therapy and gradually developed secondary sexual characteristics.

Atypical Granular Cell Tumor of the Sellar Region

We report a very rare case of atypical granular cell tumor arising in the neurohypophysis of a 56-year-old woman. The tumor was seen on radiology to be lobulated, soft and diffusely enhanced, the same as pituitary macroadenoma, but it was anatomically localized within the posterior part of the hypophysis. We partially removed the tumor via the transsphenoidal approach. The pathology showed nuclear pleomorphism, spindling features, and lymphoplasmacytic infiltration. Ki-67 and S-100 protein were focally positive in tumor cells. Histological diagnosis confirmed an atypical granular cell tumor in the sellar region, which is a rare tumor that often has the clinical appearance of a pituitary adenoma. Ophthalmologic symptoms are the most common, followed by endocrinologic manifestations. Here we describe its symptoms and radiological and pathological features.

Lymphocytic Hypophysitis: Case Report

The authors report two cases of lymphocytic hypophsitis: a 38-year-old male patient with headache and diabetes insipidus and in a 64-year-old female patient with headache. Magnetic resonance(MR) image of the patients showed mass-like lesions in the hypophysis as well as loss of high signal on T1-weighted MR images. There was evidence of hypopituitarism. Both patients underwent transsphenoidal approaches for histological diagnosis, which was compatable with lymphocytic hypophysitis. When MR image reveals a characteristic pituitary in the hypophysis lesion with relevant clinical symptoms in a patient, one should include "lymphocytic hypophysitis" as one of the diagnostic possibilities, since the therapeutic options are different from those of pituitary tumors.

A Case of Delayed Puberty due to Hypoplasia of Anterior Pituitary Gland with Pituitary Stalk Agenesis and Ectopic Neurohypophysis / 대한내분비학회지

Hypopituitarism is not a common cause of delayed puberty, however it should always be considered, especially if there are such signs as severe dwarfism, dollish face, truncal obesity, small hands and feet, and microgenitalia. Either congenital or acquired, hypopituitarism can be resulted from hypothalamic and hypophyseal lesions. The clinical feature can be diverse depending on age of the patients, rate of progression, degree of hormone deficiency and characteristics of the lesion. The recent high interest in delayed puberty and the improved detection of hypothalamic hypophyseal lesions using combined pituitary fuction stimulation test, brain CT and MRJ, has made the differential diagnosis of hypopituitarism possible as the cause of delayed puberty. MRI has shown hypophyeal hypoplasia accompanied by anterior pituitary hypoplasia and ectopic neurohypophysis in some of the patients with hypopituitasm, and although the anatomical abnormality around the hypophysis in these patients is considered the reason for hypopituitarism, the pathogensis of which has not yet to be known. We, here, report a case of delayed puberty by hypopituitarism due to hypoplasia of anterior pituitary gland, pituitary stalk agenesis and ectopic neurohypophysis with brief review of the litereature.

ULTRASTRUCTURAL OBSERVATION OF PITUICYTES IN NEUROHYPOPHYSIS OF ADULT RATS / 解剖学报

Neurohypophyses of six adult rats were observed under electron microscope toinvestigate the morphological features of pituicytes and their possible functionalsignificance.The results of morphological observation showed that the pituicytesmay be divided into 4 types,the two of which,astral pituicytes and ependymalpituicytes,obviously resemble to the neurogliocytes of central nervous system intheir morphological features.The third,dark pituicytes,was rich in mitochondria.Little was known about secretory pituicytes other than their presumable secretoryfunction suggested by the secretory granules present in their cytoplasm.The interstitial cisternae were the sites where the neurosecretory activities carriedon.The dilations of nerve fiber around the interstitial cisternae were rich in vesi-cles.It was substantiated that the pituicytes can participate in supporting andnourishing the nerve fibers,removing cell debris and may also serve a function oftransferring excitation,because of the presence of gap junction between pituicytes andynapselike contact between pituicyte and the nerve fiber.

ELECTRON MICROSCOPIC STUDY OF THE RELATIONSHIP BETWEEN CATECHOLAMINERGIC AND PEPTIDERGIC NERVE TERMINALS IN THE RAT NEUROHYPOPHYSIS / 解剖学报

In order to clarify the regulatory mechanism of the neurohormone releasing in the neurohypophysis, the immunohistochemical and chemical lesion method were combined to demonstrate the vasopressin (VP)-and catecholamine (CA)-containing nerve terminals, and their distribution and relationship were observed under electron microscopic level. The results showed that in the rat neurohypophysis there were not only widely distributed VP nerve terminals, but also there were many 6-OHDA induced degenerated nerve endings. The close relationship even synapse-like contacts existed between the CA-ergic endings and pituicytes as well as microglial cells. It was very interesting that the CA-ergic boutons formed axoaxonic synapses with VP-containing boutons. In this case, the CA-bouton was presynaptic element whereas the VP-bouton served as postsynaptic element. The above mentioned results probably provided ultrastructural evidence for the regulatory mechanism of the neurohormone releasing in the neurohypophysis for the first time.

ULTRASTRUCTURES AND THEIR RELATIONSHIPS OF THE NEUROHYPOPHYSIS IN THE RAT / 解剖学报

Ultrastructures of the neurohypophysis in the rats have been studied by means of electron microscopy. Besides identifying the fact that the neurosecretory substances store in the nerve terminals and release into the blood, there are also axo-axonic synaptoid structures existed between neurosecretory terminals and neuro-glial synaptoid contacts between neurosecretory terminals and pituicytes. The characteristics of these contacts mentioned above are as follows: (1) the pre-and postsynaptic membranes are insignificantly thickened; (2) clustered microvesicles are close to and attach to the presynaptic membrane; (3) the synaptic cleft is about 20 nm wide and contains various amount of electron dense materials. The authors suggest that the two kinds of synaptoid structures and pituicytes are all involved in the regulation for the releasing of the neurosecretory substances.

IMMUNOELECTRON MICROSCOPIC STUDY OF PEPTIDE SUBSTANCES IN THE RAT NEUROHYPOPHYSIS / 解剖学报

The ultrastructural localization of peptide substances——VP,SP,ENK,SRIFand distribution of peptidergic nerves in rat neurohypophysis were studied by elect-ron microscopy.The results showed that VP,SP,ENK and SRIF immunoreactiveproducts located in large granular vesicles(110-150 nm in diameter),at the surfaceof microvesicles and outer membrane of mitochondria.The VP-,SP-,ENK- andSRIF-containing nerve fibers distributed at periphery of capillaries and vicinity ofpituicytes.VP- and ENK- positive nerve terminals formed axo-axonic synapses withnegative terminals.Axo-axonic synapses also existed between two SRIF-positive ter-minals.In addition,ENK- and SP-positive terminals formed synaptoid structureswith pituicytes.The authors have discovered the VP-positive pituicytes for the firsttime.The scientific significances of present paper are as follows:(1)Several kinds ofpeptide such as VP,SP,ENK and SRIF have been identified in neurohypophysis atultrastructural level;(2)The discovery of VP-positive pituicytes and their peptide-rgic innervation imply that these structures probably participate in the regulation ofneurohormone releasing;(3)New morphological bases have been provided for theregulation of neurohormone releasing.

ELECTRON MICROSCOPY HISTOCHEMICAL OBSERVATION OF THE EFFECT OF CORTISONE ON THE ACID PHOSPHATASEOF NEUROHYPOPHYSIS / 解剖学报

Twenty-eight adult male rats were used for this study. The experimentar were injected intramuscular with 25 mg/d cortisone acetate and were killed in various intervals separately. The neurohypophysis were fixed in mixed solution of 4% paraformaldehyde and 2% glutaraldehyde in buffered cacodylate. Frozens ections were incubated in the medium of sodium glycero-phosphate and lead nitrate, postfixed in caulfield solution, dehydrated, embedded, ultrathin sectioned, stained With uranium acetate without lead citrate, and observed under EM, In the neurohypophysis of control animals, the active areas of acid phosphatase were few and were limited in lysosome and Golgi apparatus of pituicytes and endothelia of capillaries. After injection of cortisone, the lysosome of pituicytes were increased and the activity of acid phosphatase were strengthened. Besides pituicytes and endothelia cells, there were so many positive thin granules in the processes of dark pituicytes, some areas of positive reaction of AcP appeared in neurosecretion fibers. After increasing the drug dosage, positive reaction of AcP areas showed a tendency of expansion. In this study, we discussed the effect of cortisone on the AcP of neurohypophysis and the functional significance of pituicytes in neurosecretion procedure.