Pituitary stalk lesions: systematic review and clinical guidance

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 adenoma associated with xanthogranuloma

Xanthogranuloma (XG) of the sellar region is a non-neoplastic inflammatory lesion characterized histologically by recent and remote hemorrhage, necrotic debris, fibrosis, chronic inflammation, and cholesterol clefts with associated foreign-body giant cells. The inflammatory lesion was recognized by the World Health Organization in 2000. XG of the sellar region is rare. Cases of pituitary adenoma (PA) with an associated XG (PA/XG) are extremely rare, with a total of 16 cases in the literature. PA/XG lacks specific clinical and radiologic signs, making pre-operative diagnosis challenging. Herein, we report a case of PA/XG, describe the radiologic and pathologic findings, and discuss the role of so-called silent or "subclinical pituitary apoplexy" in the possible histogenesis of PA/XGs.

Nonbrain metastases seen on magnetic resonance imaging during metastatic brain tumor screening

Although metastases found during head magnetic resonance imaging (MRI) are not limited to metastatic brain tumors, the MRI is a very common method for “brain metastasis screening,” a modality that is being increasingly performed. In this review, we describe MRI findings of nonbrain metastases and discuss ways to avoid missing these lesions. Metastatic cranial bone tumors are among the most common nonbrain metastatic lesions found on head MRI, followed by leptomeningeal carcinomatosis. The other less-frequent metastatic lesions include those in the ventricle/choroid plexus, the pituitary gland and stalk, and the pineal gland. Metastases in the head and neck area, as well as cranial and intracranial lesions, should be carefully evaluated. Furthermore, direct geographical invasion, perineural spread, and double cancers should also be considered. While it is important to recognize these metastatic lesions on MRI, because they may necessitate a change in treatment strategy that could lead to an improvement in prognosis due to early introduction of therapy, nonbrain lesions should also be given greater attention, given the increasing survival of patients with cancer and advances in MRI technology, such as contrast-enhanced-3D T1-weighted imaging.

Infantile-Onset Isolated Neurohypophyseal Langerhans Cell Histiocytosis with Central Diabetes Insipidus: A Case Report

Central diabetes insipidus (CDI) is a rare disease in children and has a variety of etiologies. The major causes of CDI with pituitary stalk thickening (PST) are germinoma, Langerhans cell histiocytosis (LCH), and Lymphocytic infundibulo-neurohypophysitis, which are difficult to differentiate by imaging and require pathological diagnosis. We report a case of infantile-onset isolated neurohypophyseal LCH diagnosed by pathological findings. A 2-year-old girl presented with polydipsia and polyuria. CDI was diagnosed and treatment with oral desmopressin was initiated. Magnetic resonance imaging (MRI) of the head showed PST and absence of high-signal intensity of posterior pituitary on T1-weighted images. Follow-up MRI scans showed that the tumor mass was gradually increasing and extending posteriorly toward the area near the mamillary body. Simultaneously, anterior pituitary dysfunction was observed. She underwent a biopsy of the PST and LCH was diagnosed by immunohistochemical analysis. DNA analysis showed no BRAF V600E mutation. Monotherapy with 2-Chlorodeoxyadenosine reduced the tumor size but did not improve pituitary function. Isolated neurohypophyseal LCH should be considered in infantile-onset cases of CDI with PST. 2-CdA treatment resulted in rapid PST shrinkage. Further cases are needed to determine whether early diagnosis and treatment can prevent anterior pituitary dysfunction.

Safety of endoscopic endonasal biopsy for the pituitary stalk-hypothalamic lesions

PURPOSE

The indications for and the optimal biopsy approach in pituitary stalk-hypothalamic (PsH) lesions are controversial. Biopsies through an endoscopic endonasal approach (EEA) for PsH lesions have often been considered to cause the infundibulo-tuberal syndrome. The purpose of this study was to analyze the surgical and endocrinological safety of EEA biopsies for PsH lesions.

METHODS

A total of 39 consecutive patients who underwent an EEA biopsy between June 2011 and August 2020 in a single institute were retrospectively analyzed. The ophthalmological and endocrinological outcomes were assessed before and after surgery.

RESULTS

PsH lesions were confirmed to be diverse pathological diagnoses, ranging from lymphocytic hypophysitis to diffuse midline glioma, and the most common pathologic diagnosis was a germinoma (18 patients, 46.2%). No patients developed visual deterioration after the biopsy. In patients without preoperative panhypopituitarism, 13 out of 28 patients (46.4%) developed new anterior pituitary hormonal deficiencies after the biopsy. When the tissue was collected from the stalk, the endocrinological deterioration rate was 100% (6 of 6 patients), while the rate was 31.8% (7 of 22 patients) when tissue could be harvested from an extra-stalk lesion. The rate of newly developed permanent diabetes insipidus after surgery was 40.9% (9 of 22 patients). The median surgery time was 125 min, and there was no postoperative CSF leakage or infections noted.

CONCLUSIONS

An EEA biopsy for PsH lesions is a safe and efficient surgical method unless the tissue is collected from the stalk.

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.

Hypophysitis, the Growing Spectrum of a Rare Pituitary Disease

Hypophysitis is defined as inflammation of the pituitary gland that is primary or secondary to a local or systemic process. Differential diagnosis is broad (including primary tumors, metastases, and lympho-proliferative diseases) and multifaceted. Patients with hypophysitis typically present with headaches, some degree of anterior and/or posterior pituitary dysfunction, and enlargement of pituitary gland and/or stalk, as determined by imaging. Most hypophysitis causes are autoimmune, but other etiologies include inflammation secondary to sellar tumors or cysts, systemic diseases, and infection or drug-induced causes. Novel pathologies such as immunoglobulin G4-related hypophysitis, immunotherapy-induced hypophysitis, and paraneoplastic pituitary-directed autoimmunity are also included in a growing spectrum of this rare pituitary disease. Typical magnetic resonance imaging reveals stalk thickening and homogenous enlargement of the pituitary gland; however, imaging is not always specific. Diagnosis can be challenging, and ultimately, only a pituitary biopsy can confirm hypophysitis type and rule out other etiologies. A presumptive diagnosis can be made often without biopsy. Detailed history and clinical examination are essential, notably for signs of underlying etiology with systemic manifestations. Hormone replacement and, in selected cases, careful observation is advised with imaging follow-up. High-dose glucocorticoids are initiated mainly to help reduce mass effect. A response may be observed in all auto-immune etiologies, as well as in lymphoproliferative diseases, and, as such, should not be used for differential diagnosis. Surgery may be necessary in some cases to relieve mass effect and allow a definite diagnosis. Immunosuppressive therapy and radiation are sometimes also necessary in resistant cases.

Sellar, suprasellar, and parasellar masses: Imaging features and neurosurgical approaches

The sellar, suprasellar, and parasellar space contain a vast array of pathologies, including neoplastic, congenital, vascular, inflammatory, and infectious etiologies. Symptoms, if present, include a combination of headache, eye pain, ophthalmoplegia, visual field deficits, cranial neuropathy, and endocrine manifestations. A special focus is paid to key features on CT and MRI that can help in differentiating different pathologies. While most lesions ultimately require histopathologic evaluation, expert knowledge of skull base anatomy in combination with awareness of key imaging features can be useful in limiting the differential diagnosis and guiding management. Surgical techniques, including endoscopic endonasal and transcranial neurosurgical approaches are described in detail.

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.

Cryptorchidism is a Useful Clue for Idiopathic Hypogonadotropic Hypogonadism in Pituitary Stalk Thickening

Pituitary stalk lesions can represent a wide range of pathologies. The exact cause is often unknown due to hesitancy to proceed with biopsy. We present a 16-year-old adolescent who presented with delayed puberty, short stature and bilateral cryptorchidism. He was found to have a thickened pituitary stalk of uncertain etiology with partial hypopituitarism (gonadotrophin and growth hormone deficiency) on further assessment. The presence of bilateral cryptorchidism and micropenis represents lack of “mini puberty,” a phenomenon of activation of the hypothalamic-pituitary-gonadal (HPG) axis in-utero or within the first few months of life.¹ These key clinical features have been useful to establish an early temporal relationship and suggest a congenital origin of disease. This enabled a more conservative approach of surveillance to be employed as opposed to invasive pathological examination with pituitary stalk biopsy.

Diversity of Pathological Conditions Affecting Pituitary Stalk

Pituitary stalk lesions (PSL) are a very rare pathology. The majority of conditions affecting the infundibulum do not present with clinically apparent symptoms, what makes the diagnosis difficult. The recognition might be also complicated by the non-specific and transient characteristics of hormonal insufficiencies. In our study, we retrospectively analysed demographic, biochemical, and clinical long-term data of 60 consecutive, unselected adult patients (34 women and 26 men) with PSL diagnosed in the Department of Endocrinology, Jagiellonian University in Krakow. The diagnosis of PSL were categorized as confirmed, probable, or undetermined in 26, 26 and 8 patients, accordingly. Given the possible aetiology congenital, inflammatory, and neoplastic stalk lesions were diagnosed in 17, 15 and 20 patients, accordingly. In eight cases the underlying pathology remained undetermined. The most common pituitary abnormality was gonadal insufficiency diagnosed in 50.8% of cases. Diabetes insipidus was detected in 23.3% of cases. In 5% of patients the pituitary function recovered partially over time. Stalk lesions were extensively discussed in the context of the current literature. Based on the published data and our own experience a diagnostic algorithm has been proposed to help physicians with the management of patients with this challenging condition.

A Case of Burnt-Out Langerhans Cell Histiocytosis Presenting as Postpartum Hypopituitarism

Objective

To evaluate the case of a woman who presented with central hypogonadism and diabetes insipidus and further developed a persistent cough leading to an unexpected diagnosis of burnt-out Langerhans cell histiocytosis (LCH).

Methods

Clinical and laboratory endocrine evaluation, magnetic resonance imaging, high-resolution computed tomography, and open-lung biopsy results are discussed.

Results

A 28-year-old woman presented at 10 months postpartum with polydipsia, polyuria, and amenorrhea for 3 months. Her results showed a prolactin level of 25 μg/L (reference,<23.5 μg/L), estrogen level of 91 pmol/L (reference, 110-180 pmol/L), follicle-stimulating hormone level of 6 IU/L (reference, 2-20 IU/L), and luteinizing hormone level of 6 IU/L (reference, 2-70 IU/L). A water-deprivation test found a sodium concentration of 148 mmol/L (reference, 135-145 mmol/L), serum osmolality of 310 mmol/kg (reference, 275-295 mmol/kg), and urine osmolality of 107 mmol/kg (reference, 50-1450 mmol/kg) that improved to 142 mEq/L, 295 mmol/kg, and 535 mmol/kg, respectively, after desmopressin administration. Gadolinium-enhanced pituitary magnetic resonance imaging demonstrated a markedly thickened stalk with uniform enhancement. Chest high-resolution computed tomography confirmed bilateral upper-zone cystic lung disease suggestive of either pulmonary lymphangioleiomyomatosis or LCH. Eventual histology showed CD1a-positive burnt-out LCH. This differentiation was crucial as pulmonary lymphangioleiomyomatosis exacerbates with estrogen therapy and pregnancy, which the patient was able to successfully pursue without disease exacerbation.

Conclusion

The patient's initial presentation was considered as lymphocytic hypophysitis, but subsequent cystic changes on high-resolution computed tomography led to a unifying definitive diagnosis of burnt-out LCH. This case highlights the importance of investigating for uncommon secondary causes of hypophysitis.

Resection of an Isolated Pituitary Stalk Epidermoid Cyst Through a Pretemporal Approach: Case Report and Review of the Literature

BACKGROUND

Intracranial epidermoid cysts are congenital epidermal inclusion cysts derived from ectodermal origin with desquamated skin. The majority of these cysts occur in the cerebellopontine angle cistern. Epidermoid cyst of the pituitary stalk, however, is a rare location. To date, only 4 previous cases have been reported.

CASE DESCRIPTION

A 63-year-old male presented to our clinic with migraine headaches, dizziness, increased thirst, increased urinary frequency, and impotence. Magnetic resonance imaging of the brain demonstrated a rim-enhancing cystic mass with diffusion restriction on diffusion-weighted imaging located within the pituitary stalk. The patient underwent a pretemporal approach with gross total resection of the cyst. The patient's postoperative course was uneventful with no new deficits and/or endocrinopathies.

CONCLUSION

Epidermoid cyst of the pituitary stalk is an unusual and rare presentation. Four other cases treated via endoscopic approaches have been previously reported in the neurosurgical literature. To our knowledge this is the first case description of an infundibular epidermoid cyst pressing with isolated diabetes insipidus surgically treated via a transcranial pretemporal approach with gross total resection. The patient had a smooth and uneventful postoperative course with persistent diabetes insipidus.

Central diabetes insipidus caused by a pituitary stalk germinoma resembling infundibuloneurohypophysitis

We report the case of a pituitary stalk germinoma initially misdiagnosed and treated as infundibuloneurohypophysitis (INH). A 27-year-old man presented with a 1-year history of polydipsia, polyuria, nycturia consistent with central diabetes insipidus and a hyperintense pituitary stalk lesion on MRI. A possible INH diagnosis was considered, after excluding other pathologies. Lesion biopsy was discarded at that time on the ground of a small target and the high risk of added morbidity. Oral desmopressin led to initial symptoms resolution but, in the following months, an anterior panhypopituitarism developed, in spite of appropriate treatment and, by that time, the brain MRI also revealed lesion growth, which prompted a biopsy recommendation. The pathology analysis revealed a germinoma. After chemotherapy and radiotherapy, there was complete disappearance of the pituitary lesion, but the panhypopituitarism persisted. In conclusion, this case highlights the importance and difficulty of precise diagnosis in the initial assessment of pituitary stalk lesions and the need for close monitoring of treatment response. Diagnostic reassessment and biopsy in atypical cases is the only path to achieve the correct diagnosis and treatment.

Multiple endocrinological failures as a clinical presentation of a metastatic lung adenocarcinoma

SUMMARY

Multiple endocrine metastases are a rare but possible complication of lung adenocarcinoma (LAC). Pituitary metastasis is a rare condition with poor clinical expression. Diabetes insipidus (DI) is its most common presenting symptom. Here we report an original case of a pituitary stalk (PS) metastasis from LAC presenting as central DI followed by adrenal insufficiency (AI) from bilateral adrenal metastasis, without known evidence of the primary malignancy. A 45-year-old woman whose first clinical manifestations were polyuria and polydipsia was admitted. She was completely asymptomatic with no cough, no weight loss or anorexia. Chest radiography was normal. Brain MRI showed a thick pituitary stalk (PS). DI was confirmed by water restriction test and treated with vasopressin with great clinical results. Explorations for systemic and infectious disease were negative. Few months later, an acute AI led to discovering bilateral adrenal mass on abdominal CT. A suspicious 2.3 cm apical lung nodule was found later. Histopathological adrenal biopsy revealed an LAC. The patient received systemic chemotherapy with hormonal replacement for endocrinological failures by both vasopressin and hydrocortisone. We present this rare case of metastatic PS thickness arising from LAC associated with bilateral adrenal metastasis. Screening of patients with DI and stalk thickness for lung and breast cancer must be considered. Multiple endocrine failures as a diagnostic motive of LAC is a rare but possible circumstance.

LEARNING POINTS

Adrenal metastasis is a common location in lung adenocarcinoma; however, metastatic involvement of the pituitary stalk remains a rare occurrence, especially as a leading presentation to diagnose lung cancer. The posterior pituitary and the infundibulum are the preferential sites for metastases, as they receive direct arterial blood supply from hypophyseal arteries. Patients diagnosed with diabetes insipidus due to pituitary stalk thickness should be considered as a metastasis, after exclusion of the classical systemic and infectious diseases. The diagnosis of an endocrinological metastatic primary lung adenocarcinoma for patients without respiratory symptoms is often delayed due to a lack of correlation between endocrinological symptoms and lung cancer. The main originality of our case is the concomitant diagnosis of both endocrinological failures, as it was initiated with a diabetes insipidus and followed by an acute adrenal insufficiency.

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.

Imaging findings in hypophysitis: a review

Hypophysitis (HP) is a rare acute or chronic inflammatory condition of the pituitary gland. The greatest challenge in the management of HP is establishing a diagnosis through clinical criteria and non-invasive methods and predicting the patients' clinical outcome. The aim of this review is to describe the neuroradiological findings of this rare disease, providing some information regarding the possible differential diagnosis in order to avoid unnecessary surgery. Gadolinium-enhanced pituitary magnetic resonance imaging (MRI) is considered the neuroradiological investigation of choice. The features suggestive for HP include an enlarged triangular- or dumbbell-shaped gland with a thickened and not obviously deviated stalk, further supported by the absence of posterior pituitary bright spot on T1weighted images, particularly in patients presenting with diabetes insipidus. Contrast enhancement pattern is quite variable; dural enhancement has been reported in some cases after intravenous contrast administration. The characterization of the unusual sellar mass is not straightforward and generally results in a wide differential. HP should be primarily differentiated from pituitary adenomas (including pituitary apoplexy), from pituitary metastases, and from other sellar and parasellar tumors, e.g., craniopharyngiomas, germinomas, gliomas, lymphomas, meningiomas, pituicytomas, chordomas, teratomas, dermoids and epidermoids, Rathke's cleft cysts, and abscesses. In patients suspected for secondary forms related to systemic pathology, additional imaging is helpful in identifying other involved sites. Neuroradiologists need to know MRI appearance of this rare disease, as well as its typical symptoms and serological markers. A strict collaboration with endocrinologists and neurosurgeons is mandatory in order to reach a definitive diagnosis, allowing to promptly initiating an appropriate treatment.

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.

A UNIQUE CASE OF CENTRAL HYPOPITUITARISM AND CENTRAL DIABETES INSIPIDUS CAUSED BY DIFFUSE LARGE B-CELL LYMPHOMA

OBJECTIVE

To present the case of a 39-year-old male admitted to the hospital with diabetes insipidus as a sequela of a previously undiagnosed diffuse large B-cell lymphoma. This case is unique, as the patient's disease was determined to be an infiltrative malignancy affecting the pituitary infundibular stalk, resulting in multifocal pituitary dysfunction.

METHODS

Case report.

RESULTS

Initially presenting with gastrointestinal bleed, later discovered to be from tumor infiltration of gastric vessels, diagnosis of lymphoma was made when gastrectomy became necessary for hemostasis. Subsequent hypernatremia on basic laboratory studies led to further investigation and revealed central diabetes insipidus. Magnetic resonance imaging of the pituitary was performed, showing thickening of the infundibular stalk. Additional endocrine evaluation revealed central hypothyroidism and central adrenal insufficiency.

CONCLUSION

Radiologic findings of thickened pituitary infundibulum can support the diagnosis of central diabetes insipidus when additional symptoms are present. Central diabetes insipidus due to lymphomatous infundibular stalk infiltration is an uncommon presentation of endocrine deficiency as well as malignancy; this case demonstrates the management of a critically ill patient with central hypopituitarism due to diffuse B-cell lymphoma.

Primary hypophysitis and other autoimmune disorders of the sellar and suprasellar regions

The pituitary gland and the hypothalamus can be affected by autoimmune-mediated structural and functional disruption. These autoimmune-mediated diseases occur more commonly in females and are often found during pregnancy or in the post-partum period. Autoimmune diseases can either affect parts of the pituitary or hypothalamus, or can involve both sellar and suprasellar structures. Most of these cases comprise primary hypophysitis (PRH). Over the years, there has been a tremendous increase in the number of reported PRH cases and related disorders, including hypophysitis induced by immune checkpoint inhibitors. With this increasing data, more light is being shed on the spectrum of clinical presentations, biochemical and imaging abnormalities of these disorders. Regardless, these disorders are still relatively rare. The clinical presentation can vary vastly, based on the type of pituitary cell or the area of the suprasellar region affected. The severity can range from clinically silent disease to progressive and rapid deterioration and death, likely due to unrecognized central adrenal insufficiency. Although biopsy remains a gold standard for diagnosing these disorders, the current standard of practice is biochemical assessment for hormonal deficiencies and imaging studies. In several instances, these disorders spontaneously resolve, but medical or surgical intervention might be necessary to treat symptomatic disease. Due to the subtlety and a vast spectrum of clinical manifestations which could often be asymptomatic, and the rarity of the occurrence of these diseases in clinical practice, the diagnosis can be easily missed which could potentially lead to substantial morbidity or mortality. Therefore, it is crucial to have a strong clinical suspicion and pursue timely biochemical and imaging studies to initiate prompt treatment. In this article, we review the various autoimmune conditions that affect the sellar and suprasellar structures, their diagnostic approach and management of these disorders.

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.

Difficulties in cerebrospinal fluid βhCG interpretation in a patient with an infundibular lesion

A variety of neoplastic, inflammatory and congenital conditions can cause pituitary stalk thickening. Differentiating between these causes is important as targeted treatment may be offered. Diagnostic work-up consists of a thorough history, examination, biochemical analysis and imaging. We present the case of a 33-year-old male who presented with diabetes insipidus and had pituitary stalk thickening on magnetic resonance imaging. Further investigations revealed an elevated CSF βhCG, which raised the possibility of an intracranial germ cell tumor. However, when repeated on four different assays, the βhCG levels were discordant. On serial imaging, the pituitary stalk thickening reduced slightly, which would be unexpected for a germ cell tumor. This case raises the difficulties interpreting CSF βhCG, as not all immunoassays for βhCG have been validated for use in CSF. The Roche Diagnostics Elecsys and Siemens Centaur assays have been validated for CSF βhCG, and so we advocate using one of these methods. If unavailable or serum/CSF results are ambiguous, serial MRI is appropriate, with pituitary stalk biopsy considered if the stalk measures >6.5 mm or other imaging abnormalities are present.

LEARNING POINTS

Most adult patients with central diabetes insipidus have imaging abnormalities on a pituitary MRI. The most common abnormalities are loss of the posterior pituitary bright spot and pituitary stalk thickening, both of which are non-specific.Causes of pituitary stalk thickening include neoplastic, inflammatory, infective and congenital lesions.Investigation of pituitary stalk thickening should encompass the many possible causes and include biochemical analyses as well as imaging of the chest, abdomen and pelvis. Further investigations should be guided by the clinical context, but may include testicular ultrasound, CSF analysis and pituitary stalk biopsy.Germ cell tumors involving the pituitary stalk may be suspected on clinical grounds, but in the absence of a tissue diagnosis (biopsy) confirmation may be difficult and relies on biochemical assessment of blood and possibly CSF as well as serial MRI imaging.CSF βhCG levels should be analyzed on an instrument validated for use in CSF or on multiple instruments, and the pitfalls of testing this marker (false negative in some germ cell tumors, false positives in other conditions, lack of internationally agreed reference ranges for diagnosing germ cell tumors) should be considered when interpreting the results.

Intraoperative Magnetic Resonance Imaging-Guided Biopsy in the Diagnosis of Suprasellar Langerhans Cell Histiocytosis

BACKGROUND

Magnetic resonance imaging (MRI)-guided biopsy is an emerging diagnostic technique that holds great promise for otherwise difficult to access neuroanatomy.

CASE DESCRIPTION

Here we describe MRI-guided biopsy of a suprasellar lesion located posterior and superior to the pituitary stalk. The approach was implemented successfully in a 38-year-old woman who had developed progressive visual deterioration.

CONCLUSION

Intraoperative MRI revealed the need for trajectory adjustment due to an unintended, minor deviation in the burr hole entry point, demonstrating the benefit of an MRI-guided approach. Langerhans cell histiocytosis was diagnosed after biopsy, and the lesion regressed after cladribine treatment. Technical nuances of the case are reviewed in the context of the available literature.

Treatment of Multifocal Multisystem BRAF Positive Langerhans Cell Histiocytosis with Cladribine, Surgery and Allogenic Stem Cell Transplantation

Langerhans cell histiocytosis (LCH) is a very rare disease in adults and as well a very rare cause of sellar expansion. The clinical presentation can be heterogeneous, from a single bone lesion to potentially fatal, widespread disease. We describe the difficulties with the diagnosis and treatment of LCH as well as successful treatment with cladribine chemotherapy and allogeneic stem cell transplantation.