Magnetic resonance imaging of sellar and juxtasellar abnormalities in the paediatric population: an imaging review

Diagnosing and treating anterior pituitary hormone deficiency in pediatric patients

Hypopituitarism, or the failure to secrete hormones produced by the anterior pituitary (adenohypophysis) and/or to release hormones from the posterior pituitary (neurohypophysis), can be congenital or acquired. When more than one pituitary hormone axis is impaired, the condition is known as combined pituitary hormone deficiency (CPHD). The deficiency may be primarily due to a hypothalamic or to a pituitary disorder, or concomitantly both, and has a negative impact on target organ function. This review focuses on the pathophysiology, diagnosis and management of anterior pituitary hormone deficiency in the pediatric age. Congenital hypopituitarism is generally due to genetic disorders and requires early medical attention. Exposure to toxicants or intrauterine infections should also be considered as potential etiologies. The molecular mechanisms underlying the fetal development of the hypothalamus and the pituitary are well characterized, and variants in the genes involved therein may explain the pathophysiology of congenital hypopituitarism: mutations in the genes expressed in the earliest stages are usually associated with syndromic forms whereas variants in genes involved in later stages of pituitary development result in non-syndromic forms with more specific hormone deficiencies. Tumors or lesions of the (peri)sellar region, cranial radiation therapy, traumatic brain injury and, more rarely, other inflammatory or infectious lesions represent the etiologies of acquired hypopituitarism. Hormone replacement is the general strategy, with critical periods of postnatal life requiring specific attention.

Finding its place on the spectrum of pituitary duplication disorders, duplication of pituitary stalk: A case report with brief review of literature

Pituitary gland duplication is a rare abnormality and isolated duplication of the pituitary stalk without any pituitary anomaly is an even rarer entity with this case being the first documented case till date. Although incidentally discovered cases of duplication of pituitary gland (DPG) have been reported, sometimes with a duplicated pituitary stalk, patients with this disorder usually present with other craniofacial abnormalities. Consequently, DPG plus syndrome is used as it is often accompanied by endocrine disturbances and pathologies such as median cleft face syndrome, ocular disorders, craniocervical bony abnormalities, vascular anomalies and tuberomammillary masses. Since this is the first reported case without any additional pituitary gland anomaly, we propose the acronym DPS (duplication of pituitary stalk) to be used to unify this entity as we are certain that much like the previously described pituitary duplication disorders, more cases will be documented independently rather than under the umbrella of pituitary duplication disorders. This is critical as the life expectancy (age of diagnosis) in the cases reviewed in our study is as good as normal population with no obvious increase in mortality as compared to existing pituitary duplication syndromes. We present a case report of a 2 year 7 month old girl who was referred by the paediatrician for evaluation of premature thelarche. The duplication of the pituitary stalk along with mega cisterna magna and tuberomammillary fusion was the only positive finding on imaging with the pituitary gland being absolutely normal.

Ectopic pituitary neuroendocrine tumor arising in the sphenoid sinus with an avid 18F-fluorodeoxyglucose uptake masquerading as malignancy: A case report

Ectopic pituitary neuroendocrine tumors (PitNETs) are uncommon conditions that develop outside of the sella turcica. The sphenoid sinus is the most common site for ectopic PitNET, followed by the suprasellar region, clivus, and cavernous sinus. PitNETs, regardless of whether inside or outside sella, may display avid 18F-fluorodeoxyglucose (FDG) uptake and masquerade as malignant tumors. Herein, we report a case of ectopic PitNET arising in the sphenoid sinus, which was found as an FDG-avid mass during cancer screening. On magnetic resonance imaging, the tumor showed heterogeneous and intermediate signal intensity areas on T1- and T2-weighted images with cystic components, which was consistent with PitNET. The localization and the presence of empty sella were suggestive of ectopic PitNET, and the diagnosis of ectopic PitNET (prolactinoma) was confirmed by endoscopic biopsy. Ectopic PitNET should be considered in a mass similar in nature to an orthogonal PitNET in areas near the sella turcica especially in patients with empty sella.

Dorsoventral splitting of the infundibulum in a child with pituitary hypoplasia

Pituitary development arises from ectodermal tissue creating Rathke's pouch and ultimately the adenohypophysis anteriorly whereas neuroectodermal tissue arising from the diencephalon creates the neurohypophysis posteriorly. Alterations in pituitary development can lead to hormonal dysregulation and dysfunction. Following clinical suspicion of pituitary endocrinopathy, MRI plays a vital role in identifying and characterizing underlying structural abnormalities of the pituitary gland, as well as any associated extrapituitary findings. Here we report a case of an 18-month-old female presenting with short stature and growth hormone deficiency. MRI was notable for a shallow sella turcica, a hypoplastic adenohypophysis, thin pituitary stalk, and ectopic neurohypophysis. Interestingly, the pituitary stalk was noted to split dorsoventrally with a split pituitary bright spot and T1 hypointense lobe hypothesized to represent separation of the posterior pituitary lobes.

Imaging Features of Ectopic Tissues and Their Complications: Embryologic and Anatomic Approach

Ectopic tissue is an anatomic abnormality in which tissue develops in an area outside its normal location. It is primarily caused by abnormalities during the process of embryologic development. Although the majority of individuals with ectopic tissues remain asymptomatic, various symptoms and associated complications can occur. Failure in normal embryologic development leads to loss of normal physiologic function or may result in harmful functions such as ectopic hormonal secretion in the ectopic pituitary adenoma. Ectopic tissues may also frequently mimic tumors. For example, developmental abnormalities in the pharyngeal pouches may result in an ectopic parathyroid gland and ectopic thymus, both of which are frequently misdiagnosed as tumors. Adequate knowledge of embryology is essential for understanding the differential diagnoses of ectopic tissues and facilitating appropriate management. The authors summarize the embryologic development and pathogenesis of ectopic tissues by using illustrations to facilitate a deeper understanding of embryologic development and anatomy. Characteristic imaging findings (US, CT, MRI, and scintigraphy) are described for ectopic tissues of the brain, head, neck, thorax, abdomen, and pelvis by focusing on common conditions that radiologists may encounter in daily practice and their differential diagnoses. ^©RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Corpus callosal lipoma in a young adult with extracranial extension, presenting as a frontal scalp swelling: A rare case report

Intracranial lipomas are rare congenital lesions of the pediatric age group and incidental findings in neuroimaging studies, but some are associated with other congenital malformations. They are usually located in the interhemispheric fissure, often in the vicinity of the corpus callosum. Most of the intracranial lipomas are asymptomatic and require no therapy. The diagnosis is usually made based on the imaging findings and doesn't need histologic conformation. The author presents here the imaging findings of a corpus callosal lipoma with unusual extracranial extension in a 30-year-old male, highlighting the need for a complete evaluation of each patient presenting with a scalp lesion before any intervention, irrespective of the age group.

Prevalence of pituitary cysts in children using modern magnetic resonance imaging techniques

BACKGROUND

Pituitary pars intermedia/Rathke cleft cysts or cyst-like structures are commonly encountered in children undergoing brain magnetic resonance imaging (MRI), especially when examinations include thin-section, high-resolution sequences.

OBJECTIVE

To determine the prevalence of pituitary cystic lesions in children at our institution using modern MRI technique, to assess for associated endocrinopathy and to address the need for follow-up.

MATERIALS AND METHODS

We retrospectively reviewed 232 consecutive 1.5- and 3-T brain MRIs in children ages 0-18 years (mean: 8.3±5.3 years). We evaluated 3-D volumetric T1 spoiled gradient echo (SPGR) and axial T2-weighted sequences. Pituitary glands were evaluated for the presence, size and signal characteristics of cysts. Cyst volumes were measured in three orthogonal planes. Endocrine abnormalities were documented from the medical record.

RESULTS

Pituitary cysts were present in 57.7% of children (n=134), with a mean linear measurement of 3.6±1.17 mm (range: 0.4 to 12.3 mm). The overwhelming majority of cysts were hyopointense on T1-W images (n=121, 90%) and isointense on T2-W images relative to the adenohypophysis (n=106, 79%). T1 hyperintense and T2 hypointense signals were present in a minority, 6.7% and 8%, respectively. Most cysts were occult on post-contrast T1-W images (n=24, 77%). Endocrine abnormalities were present in 2/134 (1.5%) of children with cysts (these were unrelated to the pituitary gland) versus 1/98 (1%) children without cysts (P=0.7).

CONCLUSION

More often than not, pituitary cysts/cyst-like structures can be found incidentally in children using modern MRI techniques. Follow-up is not typically required if there are no associated symptoms or excessive size.

Distinct pituitary hormone levels of 184 Chinese children and adolescents with multiple pituitary hormone deficiency: a single-centre study

Background

Pituitary tumors and/or their treatment are associated with multiple pituitary hormone deficiency (MPHD) in adults, but the distinct pituitary hormone profile of MPHD in Chinese children and adolescents remains unclear.

Methods

Patients with MPHD were divided into four groups according to their MRI results: 1) pituitary stalk interruption syndrome (PSIS); 2) hypoplasia; 3) normal; and 4) tumor survivor.

Results

Among the 184 patients, 93 patients (50.5%) were with PSIS, 24 (13.0%) had hypoplastic pituitary gland, 10 (5.4%) patients were normal, and 57 (31.0%) were tumor survivors. There was an association between abnormal fetal position and PSIS (P ≤ 0.001). The CA/BA in PSIS, hypoplasia, normal, tumor survivor groups were 2.27 ± 1.05, 1.48 ± 0.39, 1.38 ± 0.57, 1.49 ± 0.33, and HtSDS were − 3.94 ± 1.39, − 2.89 ± 1.09, − 2.50 ± 1.05, − 1.38 ± 1.63. Patients in PSIS group had the largest CA/BA (P ≤ 0.001 vs. hypoplasia group, P = 0.009 vs. normal group, P ≤ 0.001 vs. tumor survivors) and lowest HtSDS (P ≤ 0.001 vs. hypoplasia group, P = 0.003 vs. normal group, P ≤ 0.001 vs. tumor survivors). The levels of TSH in the PSIS, hypoplasia, normal, and tumor survivor groups were 1.03 ± 1.08 (P = 0.149 vs. tumor survivors), 1.38 ± 1.47 (P = 0.045 vs. tumor survivors), 2.49 ± 1.53 (P < 0.001 vs. tumor survivors), and 0.76 ± 1.15 μIU/ml. The levels of GH peak in PSIS, hypoplasia, normal, tumor survivor groups were 1.37 ± 1.78, 1.27 ± 1.52, 3.36 ± 1.79, 0.53 ± 0.52 ng/ml and ACTH were 27.50 ± 20.72, 25.05 ± 14.64, 34.61 ± 59.35, 7.19 ± 8.63 ng/ml. Tumor survivors had the lowest levels of GH peak (P ≤ 0.001 vs. PSIS group, P = 0.002 vs. hypoplasia group, P ≤ 0.001 vs. normal group) and ACTH (all the P ≤ 0.001 vs. the other three groups).

Conclusion

The frequency of PSIS is high among children and adolescents with MPHD. The severity of hormone deficiencies in patients with MPHD was more important in the tumor survivor group compared with the other groups.

Imaging of the Sella and Parasellar Region in the Pediatric Population

Masses in the sella and parasellar region comprise about 10% of all pediatric brain tumors but type and frequency differs from those in adults. Imaging is critical for diagnosis and characterization of these lesions. By assessing the site of origin, signal and contrast enhancement characteristics, and the presence or absence of characteristic patterns, differential diagnosis can narrow the possibilities. The clinical presentation is often characteristic for lesion type and should be considered. This article summarizes the characteristic imaging features of the most frequent pediatric tumors and tumor-mimicking lesions in children in this region.

PITUITARY STALK INTERRUPTION SYNDROME: REPORT OF TWO CASES AND LITERATURE REVIEW

Pituitary stalk interruption syndrome (PSIS) consisting of the triad: ectopic posterior pituitary (EPP), thin or absent pituitary stalk and anterior pituitary hypoplasia is a rare pituitary malformation with variable degrees of pituitary insufficiency, from isolated growth hormone deficiency to TSH, gonadotropin and ACTH deficiency which may occur in time, with normo, hyper or hypoprolactinemia and central diabetes insipidus in up to 10% of cases. Also, extrapituitary malformations have been described in some cases. Genetic defects were identified only in 5% of cases. MRI findings are considered predictive for the endocrine phenotype. We aim to describe two cases with PSIS without central diabetes insipidus, anosmia and extrapituitary malformations, except for minor head dysmorphic features. The first case was referred at the age of 4 years for short stature (-4SDS for height, bone age 2 years), diagnosed with severe GH deficiency and developed central hypothyroidism and hypoprolactinemia during five-years follow-up. The second case, a 26 year old male with birth asphyxia, cryptorchidism, poor growth in childhood and adolescence (-3 to -4 height SDS), absent puberty and normal adult height (-1.18 SDS; bone age 15.5 years and active growth plates) had GH, TSH, ACTH deficiency and low normal PRL levels. Increasing medical awareness on PSIS clinical and endocrine heterogeneity may help a more early and accurate diagnosis. Corroboration of neuroimaging and endocrine data will improve our knowledge and understanding and will create premises for molecular diagnosis, genetic counseling and a better patients' management.