Incidental Findings on Brain Magnetic Resonance Imaging (MRI) in Pediatric Endocrine Patients

Ectopic Posterior Pituitary and Its Associations with Extrapituitary Intracranial Anomalies

Posterior pituitary ectopia is a very rare entity in the development of the pituitary gland. Several factors and multiple genes are associated with this entity causing both pituitary and extrapituitary abnormalities. Pituitary abnormalities can be various endocrine problems and extrapituitary abnormalities can be optic nerves and cerebellar hypoplasia, heterotopia, and abnormal vessels. This pictorial review represents the imaging manifestations of extrapituitary intracranial anomalies that can be associated with posterior pituitary ectopia.

Pediatric thalamic incidentalomas: an international retrospective multicenter study

OBJECTIVE

Widespread use of modern neuroimaging has led to a surge in diagnosing pediatric brain incidentalomas. Thalamic lesions have unique characteristics such as deep location, surgical complexity, and proximity to eloquent neuronal structures. Currently, the natural course of incidental thalamic lesions is unknown. Therefore, the authors present their experience in treating such lesions.

METHODS

A retrospective, international multicenter study was carried out in 8 tertiary pediatric centers from 5 countries. Patients were included if they had an incidental thalamic lesion suspected of being a tumor and were diagnosed before the age of 20 years. Treatment strategy, imaging characteristics, pathology, and the outcome of operated and unoperated cases were analyzed.

RESULTS

Overall, 58 children (23 females and 35 males) with a mean age of 10.8 ± 4.0 years were included. The two most common indications for imaging were nonspecific reasons (n = 19; e.g., research and developmental delay) and headache unrelated to small thalamic lesions (n = 14). Eleven patients (19%) underwent early surgery and 47 were followed, of whom 10 underwent surgery due to radiological changes at a mean of 11.4 ± 9.5 months after diagnosis. Of the 21 patients who underwent surgery, 9 patients underwent resection and 12 underwent biopsy. The two most frequent pathologies were pilocytic astrocytoma and WHO grade II astrocytoma (n = 6 and n = 5, respectively). Three lesions were high-grade gliomas.

CONCLUSIONS

The results of this study indicate that pediatric incidental thalamic lesions include both low- and high-grade tumors. Close and long-term radiological follow-up is warranted in patients who do not undergo immediate surgery, as tumor progression may occur.

Growth hormone replacement therapy: is it safe to use in children with asymptomatic pituitary lesions?

OBJECTIVES

Small pituitary cysts are commonly discovered on pediatric brain magnetic resonance imagings (MRIs), particularly in patients with growth hormone deficiency (GHD). We examined the need for operative management in children with these masses as well as the effect of growth hormone replacement (GHR) on these lesions.

METHODS

This was a retrospective review of pituitary protocol MRIs conducted in children 0-19 at a single center between April 2010-November 2020. Sex, indication for initial MRI, volume, and whether surgery was performed was determined. Records were reviewed to determine whether GHD was present and treatment with GHR documented. For patients with subsequent MRIs, volume on most recent scan was calculated.

RESULTS

Of the 101 children with cysts, 25 had laboratory-confirmed GHD and 76 did not. GHD patients had a higher mean age compared to no growth hormone deficiency (NGHD) cohort (11.2 and 8.4 years, respectively; p=0.02) and a larger proportion of males (p<0.001). The mean cyst volume on initial MRI was not significantly smaller in patients with GHD (0.063 ± 0.012 cm³) vs. those without GHD (0.171 ± 0.039 cm³, p=0.11). Of the 21 GHD patients who received GHR and had follow-up MRIs, 10 had no change in pituitary cyst size, two had cysts that shrank, and seven disappeared. The remaining two cysts enlarged an average of 0.061 ± 0.033 cm³. Zero GHR recipients required surgical intervention.

CONCLUSIONS

Small sellar cysts discovered incidentally on imaging in children are unlikely to require surgical intervention. GHR does not appear to significantly enlarge these pediatric pituitary lesions and is safe for use.

A minority of patients with functional seizures have abnormalities on neuroimaging

OBJECTIVE

Functional seizures often are managed incorrectly as a diagnosis of exclusion. However, a significant minority of patients with functional seizures may have abnormalities on neuroimaging that typically are associated with epilepsy, leading to diagnostic confusion. We evaluated the rate of epilepsy-associated findings on MRI, FDG-PET, and CT in patients with functional seizures.

METHODS

We studied radiologists' reports from neuroimages at our comprehensive epilepsy center from a consecutive series of patients diagnosed with functional seizures without comorbid epilepsy from 2006 to 2019. We summarized the MRI, FDG-PET, and CT results as follows: within normal limits, incidental findings, unrelated findings, non-specific abnormalities, post-operative study, epilepsy risk factors (ERF), borderline epilepsy-associated findings (EAF), and definitive EAF.

RESULTS

Of the 256 MRIs, 23% demonstrated ERF (5%), borderline EAF (8%), or definitive EAF (10%). The most common EAF was hippocampal sclerosis, with the majority of borderline EAF comprising hippocampal atrophy without T2 hyperintensity or vice versa. Of the 87 FDG-PETs, 26% demonstrated borderline EAF (17%) or definitive EAF (8%). Epilepsy-associated findings primarily included focal hypometabolism, especially of the temporal lobes, with borderline findings including subtle or questionable hypometabolism. Of the 51 CTs, only 2% had definitive EAF.

SIGNIFICANCE

This large case series provides further evidence that, while uncommon, EAF are seen in patients with functional seizures. A significant portion of these abnormal findings are borderline. The moderately high rate of these abnormalities may represent framing bias from the indication of the study being "seizures," the relative subtlety of EAF, or effects of antiseizure medications.

Dealing With Brain MRI Findings in Pediatric Patients With Endocrinological Conditions: Less Is More?

Neuroimaging is a key tool in the diagnostic process of various clinical conditions, especially in pediatric endocrinology. Thanks to continuous and remarkable technological developments, magnetic resonance imaging can precisely characterize numerous structural brain anomalies, including the pituitary gland and hypothalamus. Sometimes the use of radiological exams might become excessive and even disproportionate to the patients' medical needs, especially regarding the incidental findings, the so-called "incidentalomas". This unclarity is due to the absence of well-defined pediatric guidelines for managing and following these radiological findings. We review and summarize some indications on how to, and even if to, monitor these anomalies over time to avoid unnecessary, expensive, and time-consuming investigations and to encourage a more appropriate follow-up of brain MRI anomalies in the pediatric population with endocrinological conditions.