Idiopathic Diabetes Insipidus Research Articles

Paediatric Diabetes Insipidus: A Review

Diabetes insipidus is a disease characterized by partial or total inability to concentrate urine due to a vasopressin secretion deficiency (central diabetes insipidus), a resistance to its action (nephrogenic diabetes insipidus) or an excessive consumption of water (primary polydipsia). The main signs and symptoms of the disease are polydipsia, polyuria, and nocturia; central diabetes insipidus has an insidious onset, whereas nephrogenic diabetes insipidus has a gradual onset. Because of the advances in clinical, laboratory, imaging techniques and molecular biology, the etiologic diagnosis of diabetes insipidus has improved, from 50% of patients with idiopathic diabetes insipidus to 10%-20% of patients; therefore, it has been achieved more timely treatments, resulting in reduction of the risk of sequelae. Accordingly, it is pivotal to rule out secondary causes of diabetes insipidus, such as drug consumption or metabolic disorders in patients with nephrogenic diabetes insipidus, brain tumors, encephalic trauma, infiltrative diseases, autoimmune disorders or central nervous system infections in case of patients suffering from central diabetes insipidus. Regarding treatment, it is recommended the use of desmopressin, an analogue of vasopressin, for the treatment of central diabetes insipidus, whereas water consumption, decrease of salt consumption and treatment with diuretic and non-steroidal anti inflammatory drugs are recommended for treatment of patients with nephrogenic diabetes insipidus.
 DS (Child) H J 2021; 37(1): 64-70

MON-285 Clinical Characteristics of Six Patients with Infundibulo-Neurohypophysitis

Background: To date, precise pathological studies and the improvement of imaging studies have made it clear that a part of idiopathic diabetes insipidus (DI) could be lymphocytic infundibulo-neurohypophysitis (LINH) caused by autoimmune abnormality. Recently, anti-rabphilin (RPH) 3A antibody was identified and expecting as a useful diagnostic marker of LINH*. Objective: Here, we present the clinical course of 6 patients with central DI (CDI) who were thought to be due to LINH and compared with results of serum anti- RPH3A antibody in each. Patients and methods: Clinical characteristics of 6 patients with CDI regarded as due to LINH (M/F; 3/3, age range; 26–67 years old) were investigated. Clinical course, anterior pituitary functions, MRI findings, complications and results of serum anti-RPH3A antibody were retrospectively analyzed by medical charts. Pituitary biopsy was conducted in 2 patients. Results: On the T1-weighted MR image, one patient (# 3: 67 F) had only a lacking of high signal intensity in the posterior lobe. Thickening of pituitary stalk was seen in other 5 patients. Anti-RPH3A antibody was studied in those 5 patients and positive in 3 and negative in 2. Anterior pituitary function was preserved in 2 patients with positive anti-RPH3A antibody. One patient (#1: 26 F) was diagnosed as LINH by changes in MRI findings over time and the other patient (#5: 41 M) by pituitary biopsy. Impaired anterior pituitary function was observed in 2 of 6 patients. One patient (# 2: 32 F) suffered from CDI since late pregnancy. She had a history of massive bleeding at delivery. Postpartum evaluation revealed that besides CDI, she had TSH, ACTH and GH deficiency. Anti-RPH3A antibody was positive in this patient. A mild low GH response (not severe GHD) to GHRP-2 test was seen in another patient (#4: 37 M). Pituitary biopsy of this patient revealed that infiltration of lymphocytes distributed not only posterior but also anterior pituitary. Anti-RPH3A antibody was negative in this patient. As a complication, Type 2 DM in 2 patients, Graves’ disease and cerebral infarction in one each were observed. Conclusion: Anti-RPH3A antibody was useful as a non-invasive diagnostic marker for LINH. However, among patients who were inferred to have LINH, the clinical course, a degree of extension and severity of inflammation in the pituitary region varied from case to case, suggesting that the clinical features of LINH might be diverse. *: JCEM 100: E 946, 2015

Incidence of pituitary autoantibodies in idiopathic diabetes insipidus.

Diabetes insipidus is a disorder resulting from insufficient action of vasopressin (ADH) characterized by excretion of highly diluted urine in large amounts. Idiopathic diabetes insipidus is associated with the presence of both autoantibodies against ADH-secreting neurons and pituitary autoantibodies. The aim of the present study was to evaluate the occurrence of autoantibodies against the pituitary microsomal fraction. The study included 33 sera of diabetes insipidus patients and 10 control sera obtained from 10 healthy persons. In all patients the secretion of pituitary hormones and thyroid autoantibodies was assessed. Human pituitaries were obtained during autopsy and homogenized in 0.01 mol/l pH 7.4 phosphate buffer. In addition, for the autoantibody evaluation, the electrophoretic method of separation in polyacrylamide gel and western blot were employed. Among the 33 subjects, in 23 patients the presence of autoantibodies against the pituitary was shown. Sera of 15 patients reacted with the pituitary microsomal fraction protein of 55 kDa. In other cases, 10 sera reacted with the pituitary antigen of 67 kDa. In addition, 5 sera reacted with the 60 kDa antigen, 5 sera with 52 kDa protein, 3 sera with 105 kDa protein, 3 sera with the 97 kDa antigen and 2 sera with pituitary antigen of 92 kDa weight. In our study, based on the immunoblotting method, we observed that pituitary autoantibodies against 55, 60 and 67 kDa antigens occurred frequently.

Cardiovascular autonomic dysfunction in patients with idiopathic diabetes insipidus.

Central diabetes insipidus (DI) is a rare disease characterized by the excretion of excessive volumes of dilute urine due to reduced levels of the antidiuretic hormone arginine vasopressin (AVP), caused by an acquired or genetic defect in the neurohypophysis. The aim of this study was to identify any autonomic dysfunction (AD) in patients with DI as a possible cofactor responsible for their reportedly higher mortality. The study involved 12 patients (6 females) with central idiopathic DI and a well-controlled electrolyte balance, and 12 controls matched for age, sex and cardiovascular risk factors, who were assessed using the tilt, lying-to-standing, hand grip, deep breath, Valsalva maneuver and Stroop tests. The tilt test showed a significantly more pronounced decrease in both systolic (- 20.67 ± 18 vs. - 1.92 ± 6.99mmHg, p = 0.0009) and diastolic blood pressure (- 10.5 ± 14.29 vs. - 1.5 ± 5mmHg, p = 0.012) in patients than in controls. Three patients with DI had to suspend the test due to the onset of syncope. The lying-to-standing test also revealed a marked reduction in blood pressure in patients with DI (1.05 ± 0.13 vs. 1.53 ± 0.14, p = 0.0001). Similar results emerged for the Valsalva maneuver (Valsalva ratio, 1.24 ± 0.19 vs. 1.79 ± 0.11, p < 0.0001) and deep breath test (1.08 ± 0.11 vs. 1.33 ± 0.08, p < 0.0001). All the principal autonomic tests performed in the study were concordant in indicating that patients with central DI have an impaired autonomic nervous system function despite a normal hydroelectrolytic balance under desmopressin therapy. This impairment may reflect damage to the autonomic system per se and/or the absence of any vasoactive effect of AVP on vascular smooth muscle. In our opinion, patients with central DI should be educated on how to prevent orthostatic hypotension, and pharmacological treatment should be considered for patients with a more marked impairment.

Neuroradiological features in a cohort of 53 children with Thickened Pituitary Stalk (TPS) and/or idiopathic central diabetes insipidus

Neuroradiological features in a cohort of 53 children with Thickened Pituitary Stalk (TPS) and/or idiopathic central diabetes insipidus

A case of idiopathic diabetes insipidus presented with bilateral hydroureteronephrosis and neurogenic bladder: A pediatric case report and literature review

Diabetes insipidus (DI) is a condition with heterogeneous clinical symptoms characterized by polyuria (urine output >4 mL/kg/hr) and polydipsia (water intake >2 L/m (2)/d). In children, acquired nephrogenic DI (NDI) is more common than central DI (CDI). Diagnosis is based on the presence of high plasma osmolality and low urinary osmolality with significant water diuresis. A water deprivation test with vasopressin challenge, though has limitations, is done to differentiate NDI from CDI and diagnose their incomplete forms. Neonates and young infants are better managed with hydration therapy alone. Older children with CDI are treated with desmopressin (1-deamino-8-D-arginine vasopressin, dDAVP). Its oral form is safe, highly effective and has dosing flexibility. We report a case of an 8-year-old male patient with CDI with severe bilateral non-obstructive hydronephrosis and megaureter. Dramatic clinical and radiological responses to dDAVP treatment were achieved and therapy reduced urine volume and led to marked radiological improvement in hydronephrosis.

Langerhans Cell Histiocytosis Presenting as Endocrine Disorders in an Adult Patient: A Case Report

ABSTRACT Objective: To present a case of Langerhans cell histiocytosis (LCH) involving the pituitary and thyroid that was misdiagnosed as idiopathic diabetes insipidus (DI) and Hashimoto thyroiditis. Methods: The history, clinical findings, laboratory and imaging results, management, and follow-up of the case are presented, and the endocrine involvement is discussed. Results: A 50-year-old female with a 13-year history of DI and a 5-year history of progressive goiter with hypothyroidism had been initially diagnosed with idiopathic DI and Hashimoto thyroiditis. She also had a 10-year history of diabetes mellitus (DM). A partial thyroidectomy was conducted when the goiter caused dyspnea, and the postoperative pathological results suggested LCH. After a thorough examination, the diagnosis of LCH was confirmed, and the patient was treated with chemotherapy and radiotherapy. After the treatment, she went into persistent remission. Conclusion: LCH cases mainly presenting as endocrine disorders are very rare, and the diagnosis tends to be delayed or missed due to atypical clinical manifestations. Lesions or functional disorders of the pituitary and thyroid need to be differentially diagnosed against LCH of these organs. Appropriate therapy and long-term follow-up are necessary for the management of endocrine LCH. Abbreviations: CT computed tomography DI diabetes insipidus DM diabetes mellitus LCH Langerhans cell histiocytosis MRI magnetic resonance imaging TSH thyroid-stimulating hormone

Nephrotic syndrome complicated by idiopathic central diabetes insipidus

There is ongoing discussion regarding the mechanisms underlying edema formation in nephrotic syndrome (NS). Many studies published in the last decade reported that primary renal sodium retention was a major factor in edema formation. However, many of the factors influencing edema formation in NS remain unclear, including the role of arginine vasopressin (AVP). We report a 12-year-old boy with steroid-dependent NS complicated by idiopathic central diabetes insipidus (CDI). He did not develop edema during his first relapse of NS after developing CDI, despite having hypoalbuminemia. He had polydipsia, polyuria, low urine osmolality, and a low serum arginine AVP level. His fractional excretion of sodium was only slightly low. Endocrinological testing and magnetic resonance imaging revealed idiopathic CDI. After starting desmopressin therapy, he developed edema when his NS relapsed. This is the first known reported case of NS in a patient with CDI. The findings suggest that appropriate AVP secretion in response to an increase in serum osmolality caused by renal sodium retention is necessary for excess extracellular fluid accumulation in NS. Further investigation is needed to more fully understand the role of AVP in edema formation in NS.

A Rare Case of MRI Negative Pituitary Germinoma

To the Editor: Magnetic resonance imaging (MRI) is the preferred imaging modality to evaluate pituitary tumors; however a normal MRI scan has to be interpreted with caution. We present a case of pituitary germinoma with a normal MRI at presentation. A 15-y-old boy was evaluated for short stature, polyuria and polydipsia in our clinic. Family history was unremarkable. Patient’s height at 6 y was 105.6 cm (5th percentile), at 13 y 128.75 cm (3rd percentile) and, at 15 y was 133.1 cm (<3rd percentile). Physical exam showed sparse pubic hair and small testes (Tanner stage 2). Laboratory evaluation revealed low IGF-1, normal thyroid function tests, elevated sodium and low urine specific gravity. Bone agewas delayed by 4 y.MRI of the brain and pituitary was normal (Fig. 1a). Patient was diagnosed with diabetes insipidus (DI) and growth failure and started on desmopressin acetate (DDAVP) and growth hormone therapy. The patient’s symptoms resolved and he grew 13 cm. Three years later he presented with fatigue and declining school performance. Physical exam showed small testes (Tanner stage 3). Hormonal evaluation showed a low free T4 and mildly elevated TSH. Thyroid hormone replacement and short duration (3-mo) testosterone therapy were started. Repeat MRI of the brain and pituitary (Fig. 1b) showed pineal gland enlargement, pituitary stalk thickening (PST) and hyperintense lesions in the basal ganglia, internal capsule and corpus callosum. Biopsy revealed pituitary germinoma. Following 6 wk of external beam radiotherapy, repeat MRI showed near complete resolution of lesions. About 32 % of childhood DI cases are idiopathic however growth failure, presentation after age five and anterior pituitary deficiencies suggest an organic etiology of DI [1]. MRI findings in pituitary germinomas include PST, loss of posterior pituitary enhancement, and pituitary gland enlargement; however these are not sensitive or specific [2]. Mootha et al. recommended that patients presenting with apparent idiopathic DI receive pituitary MRIs every 3–6 mo for 1–2 y, then every 6 mo for 5 y to rule out a structural pituitary lesion [3]. Pituitary germinomas can be occult and nonspecific, therefore a comprehensive pituitary evaluation and follow up neuroimaging is essential for an accurate diagnosis.

Anterior hypopituitarism is rare and autoimmune disease is common in adults with idiopathic central diabetes insipidus

Central diabetes insipidus is a rare clinical condition with a heterogenous aetiology. Up to 40% of cases are classified as idiopathic, although many of these are thought to have an autoimmune basis. Published data have suggested that anterior hypopituitarism is common in childhood-onset idiopathic diabetes insipidus. We aimed to assess the incidence of anterior hypopituitarism in a cohort of adult patients with idiopathic diabetes insipidus. We performed a retrospective review of the databases of two pituitary investigation units. This identified 39 patients with idiopathic diabetes insipidus. All had undergone magnetic resonance imaging scanning and dynamic pituitary testing (either insulin tolerance testing or GHRH/arginine and short synacthen testing) to assess anterior pituitary function. One patient had partial growth hormone deficiency; no other anterior pituitary hormonal deficits were found. Thirty-three percent had at least one autoimmune disease in addition to central diabetes insipidus. Our data suggest that anterior hypopituitarism is rare in adult idiopathic diabetes insipidus. Routine screening of these patients for anterior hypopituitarism may not, therefore, be indicated. The significant prevalence of autoimmune disease in this cohort supports the hypothesis that idiopathic diabetes insipidus may have an autoimmune aetiology.

Natural History of Idiopathic Diabetes Insipidus

To determine what percentage of diabetes insipidus (DI) in childhood is idiopathic and to assess the natural history of idiopathic DI. We conducted a retrospective chart review of 105 patients with DI who were born or had DI diagnosed between 1980-1989 at 3 medical centers. A second cohort of 30 patients from 6 medical centers in whom idiopathic DI was diagnosed after 1990 was evaluated retrospectively for subsequent etiologic diagnoses and additional hypothalamic/pituitary deficiencies and prospectively for quality of life. In the first cohort, 11% of patients had idiopathic DI. In the second cohort, additional hypothalamic/pituitary hormone deficiencies developed in 33%, and 37% received an etiologic diagnosis for DI. Health-related quality of life for all the patients with idiopathic DI was comparable with the healthy reference population. Only a small percentage of patients with DI will remain idiopathic after first examination. Other hormone deficiencies will develop later in one-third of those patients, and slightly more than one-third of those patients will have an etiology for the DI diagnosed. Long-term surveillance is important because tumors have been diagnosed as long as 21 years after the onset of DI. Quality of life for these patients is as good as the reference population.

Hypopituitarism due to Isolated Lymphocytic Hypothalamitis in a Young Girl

Autoimmune hypothalamitis has been implicated in idiopathic central diabetes insipidus, and lymphocytic infiltration of hypothalamus hasbeen reported in patients with lymphocytic hypophysitis manifesting as hypopituitarism with diabetes insipidus. Here, we report a case ofyoung girl who presented with visual impairment, raised intracranial tension with hypopituitarism without diabetes insipidus, whose investigationsrevealed isolated lymphocytic hypothalamitis.

From idiopathic diabetes insipidus to neurodegenerative Langerhans cell histiocytosis – an unusual presentation and progression of disease

Diabetes insipidus (DI) is rare in childhood and has a wide-ranging aetiology including the involvement of uncontrolled proliferation of dendritic cells in the hypothalamic-pituitary axis, characteristic of Langerhans cell histiocytosis (LCH). DI may manifest as a sequela of multisystem LCH disease involving skin, bone, liver, spleen and lymph nodes. In very rare cases patients diagnosed with LCH exhibit neurodegenerative changes, such as severe ataxia, tremor, dysarthria and intellectual impairment. We report a 2 1/2-year-old boy who presented initially with apparent idiopathic DI, developed anterior pituitary hormone deficiency and progressive neurological deterioration secondary to neurodegenerative LCH.

Is Idiopathic Central Diabetes Insipidus Really Idiopathic

Diabetes insipidus (DI) is an uncommon diagnosis and might be idiopathic or caused by Langerhans cell histiocytosis, brain tumors, congenital anomalies, inflammation, autoimmune conditions, or other disorders. To clarify the natural history of idiopathic DI, researchers reviewed records of two cohorts of pediatric patients diagnosed with DI at multiple referral centers in the U.S. The first cohort included 105 …

Clinical features and molecular analysis of arginine-vasopressin neurophysin II gene in long-term follow-up patients with idiopathic central diabetes insipidus

Central diabetes insipidus (DI) characterized by polyuria, polydipsia and inability to concentrate urine, has different etiologies including genetic, autoimmune, post-traumatic, among other causes. Autosomal dominant central DI presents the clinical feature of a progressive decline of arginine-vasopressin (AVP) secretion. In this study, we characterized the clinical features and sequenced the AVP-NPII gene of seven long-term follow-up patients with idiopathic central DI in an attempt to determine whether a genetic cause would be involved. The diagnosis of central DI was established by fluid deprivation test and hyper-tonic saline infusion. For molecular analysis, genomic DNA was extracted and the AVP-NPII gene was amplified by polymerase chain reaction and sequenced. Sequencing analysis revealed a homozygous guanine insertion in the intron 2 (IVS2 +28 InsG) of the AVP-NPII gene in four patients, which represents an alternative gene assembly. No mutation in the code region of the AVP-NPII gene was found. The homozygous guanine insertion in intron 2 (IVS2 +28 InsG) is unlikely to contribute to the AVP-NPII gene modulation in DI. In addition, the etiology of idiopathic central DI in children may not be apparent even after long-term follow-up, and requires continuous etiological surveillance.

Pituitary Teratoma Presenting as Central Diabetes Insipidus with a Normal MRI Finding

Dear Sir, Central diabetes insipidus (DI) is a diverse condition characterized by polydipsia and polyuria due to a defect of arginine vasopressin. Known conditions for this disorder include inflammatory, autoimmune, traumatic brain injury, and brain tumors. Brain tumors such as craniopharyngioma1 and germinoma2 are associated with Central DI. Up to 50 percent of cases of central DI are thought to be idiopathic in nature.3,4 Herein we describe an interesting case of a 17-year-old man who was diagnosed with central DI, initially thought to be idiopathic but found to have pituitary teratoma. A 17-year-old male was admitted to our hospital with a 4-month history of polyuria and polydipsia with severe thirst. Initial laboratory work revealed serum BUN 8.4 mg/dL, creatinine 0.65 mg/dL, sodium 147 mEq/l, potassium 3.9 mEq/L, chloride 108 mEq/L, calcium 9.1 mg/dL, phosphate 4.6 mg/dL, fasting plasma glucose 109 mg/dL, and hemoglobinA1C 6.0%. A thyroid function test was normal. Plasma osmolarity was 291 mOsm/kgH2O and urinary osmolarity was 79 mOsm/kgH2O. His urine output was 4 to 5 liters per day without glycosuria. Urine osmolarity increased from 115 to 297 mosm/Kg H2O after 6 hours of water deprivation. Two hours later, urine osmolarity was still under 300 mosm/KgH2O (296 mosm/KgH2O) and the serum level of the antidiuretic hormone (ADH) level was < 0.4 pg/mL. After using nasal spray with 1-desamino-8-D-arginine vasopressin (DDAVP) 10 µg, his urine osmolarity increased from 296 to 600 mosm/KgH2O. His clinical course and laboratory finding led us to suspect Central DI. No abnormality was detected in a brain MRI (Fig. 1A). A complete work-up result to find the cause of Central DI was negative and his central DI was thought to be due to idiopathic cause. Fig. 1 (A) Initial brain MRI showed normal signal intensity in the posterior pituitary gland. (B) Follow-up MRI showed 3.3 cm sized lobulated solid mass on the sella and supurasellar area involving hypothalamus and optic chiasm. He was treated with 10 µg of desmopressin nasal spray every night. His urine volume decreased to around 2 L/day. He was discharged with DDAVP and was followed monthly in an outpatient clinic. After 45 months, he presented with a headache and diplopia persisting for 1 month. A brain MRI was completed, which showed a 3.3 cm sized lobulated solid mass involving the sellar and suprasellar area (Fig. 1B). He underwent a transspenoidal excision biopsy and the biopsy result was confirmed by pituitary teratoma. He received chemotherapy and radiation therapy. Magnetic resonance imaging (MRI) is the best imaging technique for detecting subtle abnormalities of the hypothalamic-pituitary region.5 Idiopathic central DI is a diagnosis of exclusion, and is diagnosed when central DI occurs in the absence of any alteration that is known to be responsible for DI.2,5 Central DI can precede overt brain tumors. Therefore, even though idiopathic central DI is diagnosed initially with a normal brain MRI, we may need a periodic clinical follow-up and thus serial brain MRIs to detect occult brain lesions.2,6

Lymphocytic Hypophysitis with a Long Latent Period from Onset of Central Diabetes Insipidus to Development of Pituitary Enlargement

A 61-year-old man presented with central lymphocytic hypophysitis. Initial pituitary MRI imaging was normal, except for loss of the "bright spot" of the posterior lobe. A diagnosis of idiopathic diabetes insipidus was made. Two years later, pituitary gland enlargement with panhypopituitarism was detected. Eight months after commencing a replacement dose of corticosteroid, the pituitary enlargement was reduced in size. These findings resulted in a diagnosis of lymphocytic hypophysitis. In patients with idiopathic diabetes insipidus, it is important to suspect lymphocytic hypophysitis and to perform a long follow-up to repeat endocrinological examinations and pituitary imaging.

Imagerie par résonance magnétique nucléaire de la neurohypohyse

The main illness of the neural pituitary is diabetes insipidus (DI). MRI is essential if DI occurs during childhood, in order to highlight malignant germinoma prognosis of which remains excellent if the diagnosis is made as early as possible. In adults, primary intracranial tumours causing DI include craniopharyngioma, or pineal tumours. Infiltrative histicytosis is another frequent aetiology. One third of previously considered idiopathic DI is in fact auto-immune. Early MRI findings advocate for such a diagnosis. Finally, meticulous analysis of the neural pituitary imaging may avoid several pitfalls and help the analysis of adenopituitary abnormalities.

Autoimmune form of central diabetes insipidus with antibodies against vasopressin-producing hypothalamic cells

Autoantibodies against vasopressin (AVP)-producing cells of the human pituitary gland as well as conventional antibodies were determined in 67 patients with central diabetes insipidus and in 141 controls without diabetes insipidus using an immunofluorescence technique. Eleven out of 30 patients (37%) with nonfamilial idiopathic diabetes insipidus, two out of 28 patients (7%) with symptomatic diabetes insipidus and none of the control persons had AVP-cell antibodies. Antibody titres were between 1 : 2 and 1 : 32, in 8 of the 13 cases the antibodies were complement-binding. In 9 patients with idiopathic diabetes insipidus and in none of the symptomatic cases one or more autoimmune diseases were demonstrable. Demonstration of autoantibodies against AVP-cells of the pituitary in the serum of patients with so-called idiopathic diabetes insipidus indicates an autoimmune basis of the disease. This interpretation of the new antibody results is supported by a frequent association of idiopathic diabetes insipidus with recognized auto-immune diseases.

A Case of Lymphocytic Infundibuloneurohypophysitis Along with Central Diabetes Insipidus, and this Improved with Conservative Care

Idiopathic central diabetes insipidus is most likely to occur in young patients who have a clinical history of autoimmune disease. The presentation of clinical findings such as central diabetes insipidus and pituitary stalk thickening on sellar magnetic resonance imaging (MRI) in a young women would strongly suggest lymphocytic hypophysitis, which is a rare inflammatory process involving the pituitary stalk and the pituitary gland, yet this disease can sometimes regress. We describe here a young woman with lymphocytic hypophysitis. She suffered from an abrupt onset of central diabetes insipidus. Sellar MRI showed thickening of pituitary stalk and loss of high signal of normal neurohypophysis on T1-weighted image. Combind pituitary stimuat ion test showed a blunted response of GH. To avoid the potential detrimental complications of invasive diagnostic procedures for testing the pituitary function in a fertile unmarried young woman, we chose close clinical and radiologic follow-up in the proper clinical context. The requirement for DDAVP was slightly decreased over time and the MR imaging obtained serially for 6 months revealed spontaneous partial regression of the pituitary lesion. (J Korean Endocr Soc 23:142~147, 2008)