Pediatric Basal Ganglia Region Tumors: Clinical and Radiologic Features Correlated with Histopathologic Findings

[Clinical analysis of 30 cases of basal ganglia germinoma in children]

OBJECTIVE

To summarize and analyze the clinical characteristics of children with basal ganglia germinoma and to improve the level of early clinical diagnosis.

METHODS

The clinical data of children diagnosed with basal ganglia germinoma admitted to the Pediatric Surgery Ward of Peking University First Hospital from January 2013 to December 2020 were retrospectively analyzed, and descriptive statistics were used to analyze the clinical characteristics of children with basal ganglia germinoma.

RESULTS

A total of 30 patients were included in the study, 28 were male, 2 were female, the mean age at onset was (9.7±2.2) years, the median disease duration was 7 months, 27 had unilateral disease, and 3 had bilateral disease. The clinical manifestations were decreased limb muscle strength, cognitive function disorders, polydipsia, precocious puberty, intracranial hypertension, dysphonia and swallowing dysfunction. The serum and cerebrospinal fluid tumor marker alpha-fetoprotein (AFP) were normal in the 30 patients, and the serum and cerebrospinal fluid tumor marker β-human chorionic gonadotropin (β-HCG) were normal in 8 patients.The serum β-HCG was normal in 11 patients but the cerebrospinal fluid β-HCG was slightly elevated, and the serum and cerebrospinal fluid β-HCG were slightly elevated in 11 patients. A total of 33 lesions with irregular shapes were found by imaging examination, including 15 (45.5%) patchy lesions, 10 (30.3%) patchy lesions, and 8 (24.2%) round-like high-density lesions. Tumors showed obvious high-density shadows on computed tomography (CT) scan. Magnetic resonance imaging (MRI) scan of the tumors showed low or isointensity on T1WI and isointensity on T2WI, accompanied by mild peritumoral edema, hemispheric atrophy, cerebral peduncle atrophy, calcification, cystic degeneration, ventricular dilatation and wallerian degeneration. On contrast-enhanced scans, the tumor showed no enhancement or heterogeneous enhancement.

CONCLUSION

The main age of onset of germ cell tumors in the basal ganglia in children is about 10 years old, and males are absolutely dominant. The clinical features and imaging manifestations have certain characteristics. With both combined, the early diagnosis of germ cell tumors in the basal ganglia can be improved.

Classification of Gliomas and Germinomas of the Basal Ganglia by Transfer Learning

Background

Germ cell tumors (GCTs) are neoplasms derived from reproductive cells, mostly occurring in children and adolescents at 10 to 19 years of age. Intracranial GCTs are classified histologically into germinomas and non-germinomatous germ cell tumors. Germinomas of the basal ganglia are difficult to distinguish based on symptoms or routine MRI images from gliomas, even for experienced neurosurgeons or radiologists. Meanwhile, intracranial germinoma has a lower incidence rate than glioma in children and adults. Therefore, we established a model based on pre-trained ResNet18 with transfer learning to better identify germinomas of the basal ganglia.

Methods

This retrospective study enrolled 73 patients diagnosed with germinoma or glioma of the basal ganglia. Brain lesions were manually segmented based on both T1C and T2 FLAIR sequences. The T1C sequence was used to build the tumor classification model. A 2D convolutional architecture and transfer learning were implemented. ResNet18 from ImageNet was retrained on the MRI images of our cohort. Class activation mapping was applied for the model visualization.

Results

The model was trained using five-fold cross-validation, achieving a mean AUC of 0.88. By analyzing the class activation map, we found that the model's attention was focused on the peri-tumoral edema region of gliomas and tumor bulk for germinomas, indicating that differences in these regions may help discriminate these tumors.

Conclusions

This study showed that the T1C-based transfer learning model could accurately distinguish germinomas from gliomas of the basal ganglia preoperatively.

[Surgical treatment of hemispheric and subcortical gliomas adjacent to corticospinal tract in children using MR tractography and intraoperative electrophysiological monitoring]

Difficult total resection of supratentorial gliomas adjacent to the corticospinal tract (CST) is due to the high risk of its injury and disability of patients. The main methods for preventing intraoperative CST damage are preoperative MR tractography and intraoperative electrophysiological monitoring. The problem of total resection of gliomas adjacent to the CST with preservation of high functional status is difficult due to immaturity and plasticity of brain structures in children. Moreover, the advantages of MR tractography combined with intraoperative monitoring have not been described. The authors present surgical treatment of supratentorial gliomas adjacent to the CST at different anatomical levels. Patients underwent preoperative and postoperative MR tractography and intraoperative electrophysiological monitoring. MR tractography provided preoperative data on CST lesion. Intraoperative monitoring made it possible to identify and preserve CST in the depth of surgical wound. MR tractography and intraoperative electrophysiological monitoring increase resection quality in patients with hemispheric and subcortical gliomas without postoperative functional deterioration.

Precise detection of the germinomatous component of intracranial germ cell tumors of the basal ganglia and thalamus using placental alkaline phosphatase in cerebrospinal fluid

PURPOSE

The disadvantages of biopsy for lesions in the basal ganglia and thalamus include a risk of various complications, difficulty in selecting the target tissue in some cases due to indistinct neuroimaging findings and limited availability of sample tissue. Placental alkaline phosphatase (PLAP) plays a decisive role in the diagnosis and management of intracranial germ cell tumors (IGCTs) in the basal ganglia and thalamus. The present study aimed to demonstrate the ability, specificity, and optimal use of PLAP values obtained from cerebrospinal fluid (CSF).

METHODS

Twenty patients with lesions in the basal ganglia and thalamus were enrolled in this study: 11 had IGCTs and 9 had non-IGCTs. The values of PLAP and other established tumor markers in the CSF were measured in all patients before treatment.

RESULTS

The mean follow-up period was 76.0 months (range, 3-168) for all lesions. PLAP was elevated in all 11 patients with IGCTs in the basal ganglia or thalamus, whereas none of the patients with non-IGCT exhibited elevated PLAP. Thus, the sensitivity and specificity of PLAP were both 100%.

CONCLUSION

Our data demonstrated that the PLAP value can specifically identify the germinomatous component even in cases of IGCTs in the basal ganglia or thalamus with high sensitivity and specificity. PLAP is undoubtedly beneficial for the safe and timely detection of the germinomatous component of IGCTs in the basal ganglia and thalamus, because reliance on PLAP measurement enables us to avoid invasive surgical procedures and facilitates the prompt initiation of chemoradiation therapy.