Pituitary stalk thickening: the role of an innovative MRI imaging analysis which may assist in determining clinical management

Pituitary stalk thickening in pediatric patients: an underrecognized diagnosis?

Objective

Pituitary stalk thickening (PST) is a rare condition in pediatric patients. Data on PST in Latin American pediatric populations are scarce. The aim of this study was to characterize a comprehensive cohort of pediatric patients diagnosed with PST in Chile between 2020 and 2022.

Subjects and methods

Retrospective review of medical records from 2020 to 2022 of patients under 18 years old diagnosed with PST, defined as a pituitary stalk width ≥ 3 mm at the pituitary insertion and/or ≥ 4 mm at the optic chiasm. A literature review was also performed to compare the identified cases with previously published ones.

Results

Nine patients with PST were identified. Their mean age at diagnosis was 10.36 years (range 2.4-17 years). The patients' main manifestations were polydipsia and polyuria (100%) and poor growth (77.8%). Eight patients had germ cell tumors, while one patient had Langerhans cell histiocytosis. At the time of diagnosis, all patients had arginine vasopressin (AVP) deficiency, along with a deficiency in at least one anterior pituitary hormone. Germ cell tumor markers were negative in all patients. A biopsy-confirmed diagnosis was obtained in all cases. Four patients required a second biopsy. The frequency of PST due to germ cell tumors was four patients/year during the study period, which is twice the expected frequency in Chile.

Conclusion

This study, characterizing the largest cohort of pediatric patients with PST in Latin America, found germ cell tumors to be the main etiology of this condition. It is important to focus diagnostic procedures on obtaining a correct diagnosis and promptly initiating appropriate treatment in patients with PST. Regional cooperation is essential for gathering data from larger cohorts to enhance our understanding of pediatric PST and improve patient outcomes.

Cerebrospinal Fluid Metabolomic Pattern of Different Pituitary Stalk Lesions

OBJECTIVE

To describe the cerebrospinal fluid (CSF) metabolomic pattern of pituitary stalk lesions.

METHODS

CSF was collected from patients with different pituitary stalk lesions treated at Peking Union Medical College Hospital: germ cell tumor (GCT, n = 27); hypophysitis (n = 10); and Langerhans cell histiocytosis (LCH) or Erdheim-Chester disease (ECD) (LCH + ECD, n = 10). The CSF metabolome profiles were characterized by liquid chromatography-mass spectrometry (LC-MS).

RESULTS

There were 44 metabolites that significantly differed between patients with GCT and those with hypophysitis (P < .05). Between patients with GCT with CSF level of beta subunit of human chorionic gonadotrophin (β-hCG) < 5 mIU/mL and those with hypophysitis, there were 15 differential metabolites (P < .05, fold change > 1.5 or < 1/1.5). All of the metabolites had an area under the curve (AUC) above 0.7. There were 9 metabolites that significantly differed between patients with GCT and those with LCH + ECD (P < .05) and 7 metabolites had significant differences between GCT (CSF β-hCG < 5 mIU/mL) and LCH + ECD (P < .05, fold change > 1.5 or < 1/1.5). We found 6 metabolites that were significantly different between patients with hypophysitis and those with LCH + ECD (P < .05) and 5 of these had fold change more than 1.5 or less than 1/1.5. Three metabolites, 5-deoxydiplosporin, cloversaponin I, and phytosphingosine, showed excellent capabilities to differentiate the 3 disease categories. Furthermore, we identified 67 metabolites associated with clinical test results (ρ > 0.2, P < .05) and 29 metabolites showed strong correlation (ρ > 0.4, P < .05).

CONCLUSION

Our study is the first to systematically investigate the metabolomics of CSF in different pituitary stalk lesions. CSF metabolomics is a useful strategy for biomarker discovery.

Pituitary T1 signal intensity at magnetic resonance imaging is reduced in patients with obesity: results from the CHIASM study

BACKGROUND

Despite obesity being well known to be associated with several pituitary hormone imbalances, pituitary appearance in magnetic resonance imaging (MRI) in patients with obesity is understudied.

OBJECTIVE

To evaluate the pituitary volume and signal intensity at MRI in patients with obesity.

METHODS

This is a prospective study performed in an endocrine Italian referral center (ClinicalTrial.gov Identifier: NCT03458533). Sixty-nine patients with obesity (BMI > 30 kg/m2) and twenty-five subjects without obesity were enrolled. Thirty-three patients with obesity were re-evaluated after 3 years of diet and lifestyle changes, of whom 17 (51.5%) achieved a > 5% loss of their initial body weight, whereas the remaining 16 (48.5%) had maintained or gained weight. Evaluations included metabolic and hormone assessments, DEXA scan, and pituitary MRI. Pituitary signal intensity was quantified by measuring the pixel density using ImageJ software.

RESULTS

At baseline, no difference in pituitary volume was observed between the obese and non-obese cohorts. At the 3-year follow-up, pituitary volume was significantly reduced (p = 0.011) only in participants with stable-increased body weight. Furthermore, a significant difference was noted in the mean pituitary intensity of T1-weighted plain and contrast-enhanced sequences between the obese and non-obese cohorts at baseline (p = 0.006; p = 0.002), and a significant decrease in signal intensity was observed in the subgroup of participants who had not lost weight (p = 0.012; p = 0.017). Insulin-like growth factor-1 levels, following correction for BMI, were correlated with pituitary volume (p = 0.001) and intensity (p = 0.049), whereas morning cortisol levels were correlated with pituitary intensity (p = 0.007). The T1-weighted pituitary intensity was negatively correlated with truncal fat (p = 0.006) and fibrinogen (p = 0.018).

CONCLUSIONS

The CHIASM study describes a quantitative reduction in pituitary intensity in T1-weighted sequences in patients with obesity. These alterations could be explained by changes in the pituitary stromal tissue, correlated with low-grade inflammation.

Incidence and Predictors for Oncologic Etiologies in Chinese Children with Pituitary Stalk Thickening

BACKGROUND

With the increasing use of magnetic resonance imaging (MRI) in the evaluation of children with endocrine disorders, pituitary stalk thickening (PST) poses a clinical conundrum due to the potential for underlying neoplasms and challenges in obtaining a tissue biopsy. The existing literature suggests Langerhans cell histiocytosis (LCH) to be the commonest (16%) oncologic cause for PST, followed by germ cell tumors (GCTs, 13%) (CCLG 2021). As the cancer epidemiology varies according to ethnicity, we present herein the incidence and predictors for oncologic etiologies in Hong Kong Chinese children with PST.

METHODS

Based on a territory-wide electronic database, we reviewed patients aged < 19 years who presented to three referral centers with endocrinopathies between 2010 and 2022. Records for patients who underwent at least one MRI brain/pituitary were examined (n = 1670): those with PST (stalk thickness ≥ 3 mm) were included, while patients with pre-existing cancer, other CNS and extra-CNS disease foci that were diagnostic of the underlying condition were excluded.

RESULTS

Twenty-eight patients (M:F = 10:18) were identified. The median age at diagnosis of PST was 10.9 years (range: 3.8-16.5), with central diabetes insipidus (CDI) and growth hormone deficiency (GHD) being the most frequent presenting endocrine disorders. At a median follow-up of 4.8 years, oncologic diagnoses were made in 14 patients (50%), including 13 GCTs (46%; germinoma = 11, non-germinoma = 2) and one LCH (4%). Among patients with GCTs, 10 were diagnosed based on histology, two by abnormal tumor markers and one by a combination of histology and tumor markers. Three patients with germinoma were initially misdiagnosed as hypophysitis/LCH. The cumulative incidence of oncologic diagnoses was significantly higher in boys and patients with PST at presentation ≥6.5 mm, CDI or ≥2 pituitary hormone deficiencies at presentation and evolving hypopituitarism (all p < 0.05 by log-rank).

CONCLUSIONS

A higher rate of GCTs was observed in Chinese children with endocrinopathy and isolated PST. The predictors identified in this study may guide healthcare providers in Asia in clinical decision making. Serial measurement of tumor markers is essential in management.

Neoplastic Etiology and Natural Course of Pituitary Stalk Thickening

CONTEXT

Pituitary stalk thickening (PST) is often identified on magnetic resonance imaging (MRI), either incidentally or during diagnostic workup of hypopituitarism. However, the neoplastic etiology and natural course of PST are not fully understood, although this knowledge is required to establish diagnostic and surveillance strategies.

OBJECTIVE

This work aimed to investigate the neoplastic etiology and natural course of PST.

METHODS

MEDLINE/PubMed and EMBASE databases were searched up to February 2021 to identify original research investigating the etiologies of PST. The proportion of neoplastic etiology in patients with PST was meta-analytically pooled. Supplementary analysis exploring factors suggesting neoplasm was also performed. For initially indeterminate cases without confirmed diagnosis, the proportion of patients showing progression of PST during follow-up was evaluated.

RESULTS

Eighteen studies covering 1368 patients with PST were included. The pooled proportion of neoplasm was 45.2% (95% CI, 33.3%-57.8%), with substantial heterogeneity across studies (I2 = 93%). The most common neoplasm was germ cell tumor (14.0% of study population), followed by Langerhans cell histiocytosis (10.2%) and metastasis (4.7%). The studies on pediatric populations and those with more than 50% of patients having at least one pituitary hormone deficiency tended to show a higher proportion of neoplasm. The pituitary stalk was thicker in neoplasms, but the difference was not significant (pooled mean difference, 2.08 mm; P = .08). In initially indeterminate cases, 18.5% (95% CI, 7.6%-38.3%) showed progression of PST during follow-up.

CONCLUSION

PST was commonly confirmed to be neoplastic, especially in pediatric populations. As isolated PST frequently progresses, follow-up imaging is essential in initially indeterminate cases.

Pituitary Stalk Thickening: Causes and Consequences. The Children's Memorial Health Institute Experience and Literature Review

BACKGROUND

Pituitary stalk thickening (PST) is a rare abnormality in the pediatric population. Its etiology is heterogeneous. The aim of the study was to identify important clinical, radiological and endocrinological manifestations of patients with PST and follow the course of the disease.

MATERIALS AND METHODS

It is a study conducted in 23 patients (13 boys) with PST with/without central diabetes insipidus (CDI) diagnosed between 1990 and 2020 at Children's Memorial Health Institute (CMHI) in Warsaw, Poland. We analyzed demographic data, clinical signs and symptoms, radiological findings, tumor markers, hormonal results, treatment protocols and outcomes.

RESULTS

The median age at the diagnosis of PST was 9.68 years (IQR: 7.21-12.33). The median time from the onset of the symptoms to the diagnosis was 2.17 years (IQR: 1.12-3.54). The most common initially reported manifestations were polydipsia, polyuria and nocturia (82.6%); most of the patients (56.5%) also presented decreased growth velocity. Hormonal evaluation at the onset of PST revealed: CDI (91.3%), growth hormone deficiency (GHD) (56.5%), hyperprolactinemia (39%), central hypothyroidism (34.8%), adrenal insufficiency (9%), precocious puberty (8.7%). The majority of the patients were diagnosed with germinoma (seventeen patients - 73.9%, one of them with teratoma and germinoma). Langerhans cell histiocytosis (LCH) was identified in three patients (multisystem LCH in two patients, and unifocal LCH in one patient). A single case of atypical teratoid rhabdoid tumor, suspected low-grade glioma (LGG) and lymphocytic infundibuloneurohypophysitis (LINH). The overall survival rate during the observational period was 87.0%.

CONCLUSIONS

The pituitary infundibulum presents a diagnostic imaging challenge because of its small size and protean spectrum of disease processes. Germinoma should be suspected in all children with PST, especially with CDI, even when neurological and ophthalmological symptoms are absent.

Pituitary Stalk Germ Cell Tumors: Retrospective Case Series and Literature Review

OBJECTIVE

Intracranial germ cell tumors with isolated pituitary stalk involvement are rare. Early recognition and long-term monitoring deserve further exploration.

METHODS

A retrospective study reviewing eleven intracranial germ cell tumor patients with isolated pituitary stalk involvement was performed.

RESULTS

Seven boys and four girls who presented with a hyperintense pituitary stalk on postcontrast T1-weighted magnetic resonance imaging without a posterior pituitary signal were included. The average maximum width of the pituitary stalk was 5.2 ± 1.6 mm. Polydipsia and polyuria occurred in all patients, followed by growth retardation, fatigue, and amenorrhoea. Eight patients (72%) had concomitant partial anterior pituitary hormone deficiency. Seven patients initially had elevated human chorionic gonadotropin levels. After chemoradiotherapy, ten patients attended follow-up. Central diabetes insipidus remained in all survivors, and four (40%) of them had concomitant partial anterior pituitary hormone deficiency, primarily of growth hormone and insulin-like growth factor-1. The causes of the delayed diagnosis of previous studies were mainly negative tumor markers and the initial pathological diagnosis of autoimmune diseases.

CONCLUSION

Isolated pituitary stalk lesions could be a signal of intracranial germ cell tumors, especially coexisting with diabetes insipidus, hypopituitarism, and a worse response to glucocorticoid therapy. Negative results of tumor markers and pathology could not exclude the diagnosis. Chemoradiotherapy is an effective therapy, leaving mild-t-moderate hypothalamus-pituitary dysfunction. This rare neuroimaging feature may be used as a factor to predict long-term neuroendocrine outcomes.

Outcome of endoscopic transcortical intraventricular biopsy of isolated thickened pituitary stalk lesions in children

OBJECTIVE

The purpose of this study was to investigate the efficacy and safety of endoscopic transcortical intraventricular biopsy in pediatric patients with isolated thickened pituitary stalk lesions.

METHODS

From 1994 to 2018, 16 pediatric patients (8 males and 8 females) underwent endoscopic transcortical intraventricular biopsy at a single institution to establish an accurate pathological diagnosis for appropriate treatment strategies.

RESULTS

Preoperatively, the median diameter of the pituitary stalks was 5.31 ± 1.67 mm (range 3.86-9.17 mm). Overall, the diagnostic yield at endoscopic intraventricular biopsy was 93.8%. Histopathological diagnosis included germinoma (n = 10, 62.5%), Langerhans cell histiocytosis (n = 4, 25%), pilocytic astrocytoma (n = 1, 6.3%), and pituicytoma (n = 1, 6.3%). Two patients developed new diabetes insipidus after the procedure, and 3 patients had new postoperative hypothyroidism. There were no postoperative neurological deficits in this series.

CONCLUSIONS

Neuroendoscopic biopsy via the transcortical intraventricular corridor was shown to be safe and to aid in a reliable histopathological diagnosis in the management of isolated pituitary stalk lesions in pediatric patients. It can be considered a minimally invasive alternative to open biopsy via transcranial or endonasal corridors.

An Infundibular Unidentified Object (IUO): a new pituitary stalk marker?

PURPOSE

Measurement of the pituitary stalk (PS) diameter does not always solve the issue of minimal PS thickening. A previously undescribed image is found at the infundibular level on high resolution thin section T2W MRI in a large number of normal individuals. We speculate that this image-whose exact origin is still unknown-may serve as a marker of the normal infundibulum.

METHODS

In the last 6 months, 350 consecutive adult patients suspected of sellar pathology or controlled after medical or surgical treatment prospectively underwent a pituitary MRI including a sagittal T2W high resolution sequence. One hundred twelwe patients presenting a pituitary mass with suprasellar extension or those whose PS was not entirely visible were excluded.

RESULTS

A short focal annular T2 hypointense thickening of the wall of the infundibular recess of the third ventricle, more pronounced anteriorly was found in 151/238 patients. Additionally, a more or less tiny ventral extension was demonstrated on sagittal T2W sequence in 105/151 patients. These images were not identified on T1W or on T1W gadolinium enhanced sequences. The ring-like infundibular thickening and/or its ventral extension were not identified in 87/238 patients; in 43/87 of these patients the PS was found severely stretched mainly in case of primary or secondary empty sella. If patients with empty sella were excluded, our finding was observed in 194/238 cases, i.e. in 82%.

CONCLUSIONS

A detailed appearance of the PS on T2W MRI is described for the first time. A previously unreported T2W hypointense annular focal image prolonged by a tiny spicular or nodular ventral bud is found at the lower part of the infundibulum in a majority of normal patients, but not if the PS is stretched such as in empty sella. This image has to be recognized as a normal anatomical landmark. The possible origin of this image is discussed but not totally elucidated. An ongoing research will demonstrate or not if this image may serve as a marker to improve the early diagnosis of PS lesions.

Management of children and young people with idiopathic pituitary stalk thickening, central diabetes insipidus, or both: a national clinical practice consensus guideline

Unexplained or idiopathic pituitary stalk thickening or central diabetes insipidus not only harbours rare occult malignancies in 40% of cases but can also reflect benign congenital defects. Between 2014 and 2019, a multidisciplinary, expert national guideline development group in the UK systematically developed a management flowchart and clinical practice guideline to inform specialist care and improve outcomes in children and young people (aged <19 years) with idiopathic pituitary stalk thickening, central diabetes insipidus, or both. All such cases of idiopathic pituitary stalk thickening and central diabetes insipidus require dynamic pituitary function testing, specialist pituitary imaging, measurement of serum β-human chorionic gonadotropin and alpha-fetoprotein concentrations, chest x-ray, abdominal ultrasonography, optometry, and skeletal survey for occult disease. Stalk thickening of 4 mm or more at the optic chiasm, 3 mm or more at pituitary insertion, or both, is potentially pathological, particularly if an endocrinopathy or visual impairment coexists. In this guideline, we define the role of surveillance, cerebrospinal fluid tumour markers, whole-body imaging, indications, timing and risks of stalk biopsy, and criteria for discharge. We encourage a registry of outcomes to validate the systematic approach described in this guideline and research to establish typical paediatric stalk sizes and the possible role of novel biomarkers, imaging techniques, or both, in diagnosis.

A clinical approach to parasellar lesions in the transition age

Many reviews have summarised the pathology and management of the parasellar region in adult patients, although an analysis of these aspects in the transition years, from puberty onset to the age of peak bone mass, has been lacking. A comprehensive search of English-language original articles, published from 2000 to 2020, was conducted in the MEDLINE database (December 2019 to March 2020). We selected all studies regarding epidemiology, diagnosis and management of the following parasellar lesions: germinoma, craniopharyngioma, Langerhans cell histiocytosis, optic glioma, hypothalamic hamartoma, tuber cinereum hamartoma, cranial chordoma, Rathke cleft cyst, hypophysitis and hypothalamitis during the transition age from childhood to adulthood. In the present review, we provide an overview of the principal parasellar lesions occurring in the transition age. Symptoms are usually a result of the mass effect of the lesions on nearby structures, as well as anterior pituitary deficits. Diabetes insipidus occurs frequently in these patients. In this age group, pubertal developmental disorders may be more evident compared to other stages of life. Parasellar lesions in the transition age mostly include neoplastic lesions such as germinomas, hamartomas, optic gliomas, craniopharyngiomas Langerhans cell histiocytosis and chordomas, and rarely inflammatory lesions (hypophysitis, hypothalamitis). There are limited data on the management of parasellar lesions in the transition age. Endocrine evaluation is crucial for identifying conditions that require hormonal treatment so that they can be treated early to improve the quality of life of the individual patient in this complex age range. The clinical approach to parasellar lesions involves a multidisciplinary effort.

GH deficiency in cancer survivors in the transition age: diagnosis and therapy

BACKGROUND

Survival rates among childhood cancer survivors (CCSs) have significantly risen in the last 40 years due to substantial improvements in treatment protocols. However, this improvement has brought with it serious late effects that frequently involve the endocrine system. Of the endocrine disorders, GH deficiency (GHD) is the most common among CCSs as a consequence of a history of cancers, surgery, and/or radiotherapy involving the hypothalamo-pituitary region.

METHODS

A comprehensive search of English language articles regardless of age was conducted in the MEDLINE database between December 2018 and October 2019. We selected all studies on GH therapy in CCSs during the transition age regarding the most challenging topics: when to retest; which diagnostic tests and cut-offs to use; when to start GH replacement therapy (GHRT); what GH dose to use; safety; quality of life, compliance and adherence to GHRT; interactions between GH and other hormonal replacement treatments.

RESULTS

In the present review, we provide an overview of the current clinical management of challenges in GHD in cancer survivors in the transition age.

CONCLUSIONS

Endocrine dysfunction among CCSs has a high prevalence in the transition age and increase with time. Many endocrine disorders, including GHD, are often not diagnosed or under-diagnosed, probably due to the lack of specialized centers for the long-term follow-up. Therefore, it is crucial that transition specialized clinics should be increased in terms of number and specific skills in order to manage endocrine disorders in adolescence, a delicate and complex period of life. A multidisciplinary approach, also including psychological counseling, is essential in the follow-up and management of these patients in order to minimize their disabilities and maximize their quality of life.

Thyroid disorders in programmed death 1 inhibitor-treated patients: Is previous therapy with tyrosine kinase inhibitors a predisposing factor?

BACKGROUND

Programmed death 1 (PD-1) inhibitors are frequently associated with thyroid-related adverse events (TAEs), but many aspects remain unclear. This study aims to evaluate the incidence and characteristics of such events and to find any predictive factor for its development.

METHODS

We retrospectively analysed data from patients with advanced solid tumours (non-small-cell lung carcinoma, renal cell carcinoma, metastatic melanoma) treated with PD-1 inhibitors (nivolumab, pembrolizumab) in Oncology Unit B, Policlinico Umberto I of Rome, from June 2015 to December 2018. All patients underwent baseline thyroid function evaluations repeated monthly.

RESULTS

The cohort consisted of 126 patients (66.7% male, mean age 66.4 ± 9.7 years). One hundred and seven received nivolumab and 19 pembrolizumab. Twenty-three per cent of patients experienced TAEs (mainly CTCAE grade 1), with hypothyroidism in 15.1% (subclinical: 11.9%, overt: 3.2%) and hyperthyroidism in 8.0% (subclinical: 4.8%, overt: 3.2%). Median time to TAE onset was 8.7 ± 6.8 weeks (10.4 ± 7.6 weeks for hypothyroidism, 5.4 ± 3.0 weeks for hyperthyroidism). Most TAEs (89.7%) appeared within the first 3 months, none after 8 months. Most hypothyroid patients (63.2%) had previously been treated with a tyrosine kinase inhibitor (TKI). Logistic regression analysis showed that pretreatment with a TKI was a major predisposing factor for the development of hypothyroidism (OR 9.2, 95% CI: 1.4-59.9, P = .020).

CONCLUSIONS

TAEs are common during anti-PD-1 therapy and usually occur within the first 3 months of treatment. This is the first study evaluating the impact of previous oncologic therapies on TAEs, identifying TKI as a major risk factor for the development of hypothyroidism in patients treated with anti-PD-1.

Tumor T2 signal intensity and stalk angulation correlates with endocrine status in pituitary adenoma patients: a quantitative 7 tesla MRI study

PURPOSE

Pituitary adenomas are common CNS tumors that can cause endocrine dysfunction due to hormone oversecretion and by mass effect on the normal gland. The study of pituitary adenomas and adjacent sellar anatomy with high-resolution 7 T MRI may further characterize endocrine dysfunction. The purpose of this study was to determine the efficacy of 7 T MRI in identifying radiological markers for endocrine function.

METHODS

MR images obtained in 23 patients with pituitary adenomas were reviewed by consensus between three neuroradiologists. Landmarks and criteria were devised to measure radiological features of stalk, tumor, and normal gland. Fischer's exact tests and nominal logistic regression were performed.

RESULTS

Mean cross-sectional area of the stalk just below the infundibular recess was 6.3 ± 3.7 mm². Mean curvature and deviation angles were 34.2° ± 23.2° and 29.7° ± 17.3°, respectively. Knosp scores obtained differed between 7 T and lower field strength scans (P < 0.0001 [right] and P = 0.0006 [left]). Ability to characterize tumor was rated higher at 7 T compared with lower field MRI, P = 0.05. Confidence in visualizing normal gland was also higher using 7 T MRI, P = 0.036. The six hormone-secreting tumors had higher corrected T2 mean SI than non-secreting tumors (2.54 vs. - 0.38, P = 0.0196). Seven patients had preoperative hypopituitarism and had significantly greater stalk curvature angles than patients without hypopituitarism (71.7° vs. 36.55°, P = 0.027).

CONCLUSION

Radiological characterization of pituitary adenomas and adjacent native pituitary tissue may benefit with the use of 7 T MRI. Corrected T2 SI of tumor may be a sensitive predictor of hormonal secretion and may be useful in the diagnostic work-up for pituitary adenoma. 7 T MRI may be valuable in identifying markers of endocrine function in patients with pituitary adenomas. Our results indicate that hormone-secreting tumors have higher T2-weighted SI and tumors associated with preoperative hypopituitarism have greater stalk curvature angles.

Pituitary Stalk Enlargement in Adults

Pathologies involving the pituitary stalk (PS) are generally revealed by the presence of diabetes insipidus. The availability of MRI provides a major diagnostic contribution by enabling the visualization of the site of the culprit lesion, especially when it is small. However, when only an enlarged PS is found, the etiological workup may be difficult, particularly because the biopsy of the stalk is difficult, harmful and often not contributive. The pathological proof of the etiology thus needs to be obtained indirectly. The aim of this article was to provide an accurate review of the literature about PS enlargement in adults describing the differences between the numerous etiologies involved and consequent different diagnostic approaches. The etiological diagnostic procedure begins with the search for possible other lesions suggestive of histiocytosis, sarcoidosis, tuberculosis or other etiologies elsewhere in the body that could be more easily biopsied. We usually perform neck, thorax, abdomen, and pelvis CT scan; positron emission tomography scan; bone scan; or other imaging methods when we suspect generalized lesions. Measurement of serum markers such as human chorionic gonadotropin, alpha-fetoprotein, angiotensin converting enzyme, and IgG4 may also be helpful. Obviously, in the presence of an underlying carcinoma (particularly breast or bronchopulmonary), one must first consider a metastasis located in the PS. In the case of an isolated PS enlargement, simple monitoring, without histological proof, can be proposed (by repeating MRI at 3-6 months) with the hypothesis of a germinoma (particularly in a teenager or a young adult) that, by increasing in size, necessitates a biopsy. In contrast, a spontaneous diminution of the lesion is suggestive of infundibulo-neurohypophysitis. We prefer not to initiate steroid therapy to monitor the spontaneous course when a watch-and-see attitude is preferred. However, in many cases, the etiological diagnosis remains uncertain, requiring either close monitoring of the lesion or, in exceptional situations, trying to obtain definitive pathological evidence by a biopsy, which, unfortunately, is in most cases performed by the transcranial route. If a simple surveillance is chosen, it has to be very prolonged (annual surveillance). Indeed, progression of histiocytosis or germinoma may be delayed.

Late Effects of Parasellar Lesion Treatment: Hypogonadism and Infertility

Central hypogonadism, also defined as hypogonadotropic hypogonadism, is a recognized complication of hypothalamic-pituitary-gonadal axis damage following treatment of sellar and parasellar masses. In addition to radiotherapy and surgery, CTLA4-blocking antibodies and alkylating agents such as temozolomide can also lead to hypogonadism, through different mechanisms. Central hypogonadism in boys and girls may lead to pubertal delay or arrest, impairing full development of the genitalia and secondary sexual characteristics. Alternatively, cranial irradiation or ectopic hormone production may instead cause early puberty, affecting hypothalamic control of the gonadostat. Given the reproductive risks, discussion of fertility preservation options and referral to reproductive specialists before treatment is essential. Steroid hormone replacement can interfere with other replacement therapies and may require specific dose adjustments. Adequate gonadotropin stimulation therapy may enable patients to restore gametogenesis and conceive spontaneously. When assisted reproductive technology is needed, protocols must be tailored to account for possible long-term gonadotropin insufficiency prior to stimulation. The aim of this review was to provide an overview of the risk factors for hypogonadism and infertility in patients treated for parasellar lesions and to give a summary of the current recommendations for management and follow-up of these dysfunctions in such patients. We have also briefly summarized evidence on the physiological role of pituitary hormones during pregnancy, focusing on the management of pituitary deficiencies.

Etiological Spectrum and Pattern of Change in Pituitary Stalk Thickening: Experience in 321 Patients

OBJECTIVE

To summarize the etiologies of pituitary stalk thickening (PST) and the natural course of indistinguishable PST.

METHODS

Clinical information, including the symptoms at onset and laboratory, imaging, operative, pathological, and follow-up data, of patients with MRI-confirmed PST at Peking Union Medical College Hospital from January 2014 to May 2017 was collected and reviewed.

RESULTS

Of 321 eligible patients with PST, 28.3% were ≤18 years old. Central diabetes insipidus was the initial symptom in 68.8% of patients. At least one anterior pituitary hormone deficit was found in 57.6% of patients. The adjusted OR of panhypopituitarism associated with hypothalamus involvement was 7.3 (95% CI, 3.0 to 17.8; P < 0.001). Confirmed diagnoses were established in 137 patients (42.7%), including neoplasms (75.2%), inflammation (13.1%), and congenital anomalies (11.7%). Intracranial germ cell tumors (66.7%) were the leading cause among children, whereas histiocytoses (20.0%) and malignant metastases (14.7%) were the most common causes in adults. Thirty-eight patients with indistinguishable PST underwent a second MRI at a median time of 4.4 months. Spontaneous remission was observed in 17 of these patients (44.7%) after a median 8.5 months, with complete remission in 14 (36.8%) and partial remission in three (7.0%); five (13.2%) patients exhibited progression, and the remaining 16 (42.1%) stabilized.

CONCLUSION

PST is highly heterogeneous, and most confirmed cases are attributed to neoplasms. The etiological spectrum varies with age. Physicians must be familiar with the major differential diagnoses, necessary investigations, and follow-up. Biopsy is indicated when radiological progression and/or worsening of pituitary function is detected.

PITUITARY STALK THICKENING IN A LARGE COHORT: TOWARD MORE ACCURATE PREDICTORS OF PITUITARY DYSFUNCTION AND ETIOLOGY

Objective: To summarize the characteristics of patients with pituitary stalk thickening, analyze the association between pituitary stalk width and hypopituitarism, and develop a diagnostic model to differentiate neoplastic and inflammatory origins. Methods: A total of 325 patients with pituitary stalk thickening in a tertiary teaching hospital between January 2012 and February 2018 were enrolled. Basic characteristics and hormonal status were evaluated. Indicators to predict etiology in patients with histologic diagnoses were analyzed. Results: Of the 325 patients, 62.5% were female. Deficiency in gonadotropin was most common, followed by corticotropin, growth hormone, and thyrotropin. The increase in pituitary stalk width was associated with a risk of central diabetes insipidus (odds ratio [OR], 3.57; P<.001) and with a combination of central diabetes insipidus and anterior pituitary deficiency (OR, 2.28; P = .029). The cut-off pituitary stalk width of 4.75 mm had a sensitivity of 69.2% and a specificity of 71.4% for the presence of central diabetes insipidus together with anterior pituitary deficiency. Six indicators (central diabetes insipidus, pattern of pituitary stalk thickening, pituitary stalk width, neutrophilic granulocyte percentage, serum sodium level, and gender) were used to develop a model having an accuracy of 95.7% to differentiate neoplastic from inflammatory causes. Conclusion: Pituitary stalk width could indicate the presence of anterior pituitary dysfunction, especially in central diabetes insipidus patients. With the use of a diagnostic model, the neoplastic and inflammatory causes of pituitary stalk thickening could be preliminarily differentiated. Abbreviations: APD = anterior pituitary dysfunction; AUC = area under the curve; CDI = central diabetes insipidus; GH = growth hormone; MRI = magnetic resonance imaging; OR = odd ratio; PHBS = posterior hypophyseal bright spots; PST = pituitary stalk thickening; PSW = pituitary stalk width.

Single center study of 53 consecutive patients with pituitary stalk lesions

BACKGROUND

The etiological spectrum of pituitary stalk lesions (PSL) is wide and yet specific compared to the other diseases of the sellar and suprasellar region. Because of the pituitary stalk's (PS) critical location and role, biopsies of these lesions are rarely performed, and their underlying pathology is often a conundrum for clinicians. A pituitary MRI in association with a clinical context can facilitate their diagnosis.

AIM

To present the various causes of PSL-their clinical, hormonal, histopathological, and MRI characteristics in order to gain better insight into this pathology.

METHOD

A retrospective observational study consisting of 53 consecutive patients with PSL of the mean age 32 ± 4.2 years (range 6-67), conducted at the Department for Neuroendocrinology, Clinical Center of Serbia 2010-2018.

RESULTS

Congenital malformations were the most common cause of PSL in 25 of 53 patients (47.1%), followed by inflammatory (9/53; 16.9%) and neoplastic lesions (9/53; 16.9%). The exact cause of PSL was established in 31 (58.4%) patients, of whom 23 were with congenital PS abnormalities and 8 with histopathology of PSL (7 neoplastic and 1 Langerhans Cell Hystiocytosis). A probable diagnosis of PSL was stated in 12 patients (22.6%): 6 with lymphocytic panhypophysitis, while Rathke cleft cyst, tuberculosis, dissemination of malignancy in PS were each diagnosed in 2 patients. In 10 patients (18.8%), the etiology of PSL remained unknown.

CONCLUSION

Due to the inability of establishing an exact diagnosis, the management and prognosis of PSL are difficult in many patients. By presenting a wide array of causes implicated in this condition, we believe that our study can aid clinicians in the challenging cases of this pathology.

MECHANISMS IN ENDOCRINOLOGY: Hypophysitis: diagnosis and treatment

Hypophysitis is a rare condition characterised by inflammation of the pituitary gland, usually resulting in hypopituitarism and pituitary enlargement. Pituitary inflammation can occur as a primary hypophysitis (most commonly lymphocytic, granulomatous or xanthomatous disease) or as secondary hypophysitis (as a result of systemic diseases, immunotherapy or alternative sella-based pathologies). Hypophysitis can be classified using anatomical, histopathological and aetiological criteria. Non-invasive diagnosis of hypophysitis remains elusive, and the use of currently available serum anti-pituitary antibodies are limited by low sensitivity and specificity. Newer serum markers such as anti-rabphilin 3A are yet to show consistent diagnostic value and are not yet commercially available. Traditionally considered a very rare condition, the recent recognition of IgG4-related disease and hypophysitis as a consequence of use of immune modulatory therapy has resulted in increased understanding of the pathophysiology of hypophysitis. Modern imaging techniques, histological classification and immune profiling are improving the accuracy of the diagnosis of the patient with hypophysitis. The objective of this review is to bring readers up-to-date with current understanding of conditions presenting as hypophysitis, focussing on recent advances and areas for future development. We describe the presenting features, investigation and diagnostic approach of the patient with likely hypophysitis, including existing conventional techniques and those in the research/development arena. Hypophysitis usually results in acute and persistent pituitary hormone deficiency requiring long-term replacement. Management of hypophysitis includes control of the inflammatory pituitary mass using a variety of treatment strategies including surgery and medical therapy. Glucocorticoids remain the mainstay of medical treatment but other immunosuppressive agents (e.g. azathioprine, rituximab) show benefit in some cases, but there is a need for controlled studies to inform practice.

Clinical presentation and outcome of children with central diabetes insipidus associated with a self-limited or transient pituitary stalk thickening, diagnosed as infundibuloneurohypophysitis

OBJECTIVE

Despite lymphocytic or autoimmune infundibuloneurohypophysitis (INH) is an increasingly recognized aetiology in children with central diabetes insipidus (CDI); clinical data on epidemiology (clinical evolution, predisposing factors, complications), diagnosis and management of this entity are limited and mostly based on published case reports. The aim of this study was to gain a broader insight in the natural history of this disease by analysing the clinical presentation, radiological pituitary stalk changes, associated autoimmunity and hormonal deficiencies in children with CDI and a self-limiting or transient stalk thickening (ST), diagnosed as autoimmune infundibuloneurohypophysitis, during the last 15 years in four Belgian university hospitals.

DESIGN AND PATIENTS

The medical files of nine CDI patients with a ST at initial presentation and no signs of Langerhans cell histiocytosis or germinoma at presentation and/or during follow-up of more than 1.5 years were reviewed.

RESULTS

Age at presentation ranged from 3 to 14 years. Two patients had a positive family history of autoimmunity. Three children presented with associated growth failure, two with nausea and one with long-standing headache. Median maximal diameter of the stalk was 4.6 mm (2.7-10 mm). Four patients had extra-pituitary brain anomalies, such as cysts. One patient had central hypothyroidism, and another had a partial growth hormone deficiency at diagnosis. Within a mean follow-up of 5.4 (1.5-15) years, stalk thickening remained unchanged in two patients, regressed in one and normalized in six children. CDI remained in all, while additional pituitary hormone deficiencies developed in only one patient.

CONCLUSIONS

In this series of children INH with CDI as initial presentation, CDI was permanent and infrequently associated with anterior pituitary hormone deficiencies, despite a frequent association with nonstalk cerebral lesions.

Diabetes insipidus is an unfavorable prognostic factor for response to glucocorticoids in patients with autoimmune hypophysitis

INTRODUCTION

Autoimmune hypophysitis (AH) has a variable clinical presentation and natural history; likewise, its response to glucocorticoid therapy is often unpredictable.

OBJECTIVE

To identify clinical and radiological findings associated with response to glucocorticoids.

DESIGN AND METHODS

12 consecutive patients with AH, evaluated from 2008 to 2016. AH was the exclusion diagnosis after ruling out other pituitary masses and secondary causes of hypophysitis. Mean follow-up time was 30 ± 27 months (range 12-96 months).

RESULTS

MRI identified two main patterns of presentation: global enlargement of the pituitary gland or panhypophysitis (n = 4, PH), and pituitary stalk abnormality only, or infundibulo-neuro-hypophysitis (n = 8, INH). Multiple tropin defects were more common in PH (100%) than those in INH (28% P = 0.014), whereas diabetes insipidus was more common in INH (100%) than that in PH (50%; P = 0.028). All 4 PH and 4 out of 8 INH were treated with glucocorticoids. Pituitary volume significantly reduced in all PH patients (P = 0.012), defective anterior pituitary function recovered only in the two patients without diabetes insipidus (50%) and panhypopituitarism persisted, along with diabetes insipidus, in the remaining 2 (50%). In all INH patients, either treated or untreated, pituitary stalk diameter reduced (P = 0.008) but diabetes insipidus persisted in all.

CONCLUSIONS

Glucocorticoid therapy may improve anterior pituitary function in a subset of patients but has no effect on restoring posterior pituitary function. Diabetes insipidus appears as a negative prognostic factor for response to glucocorticoids.