Background: Adrenocortical tumors (ACTs) encompassing the adrenocortical adenoma (ACA), carcinoma (ACC), and tumors of undetermined malignant potential (ACx) are rare endocrine neoplasms with a poor prognosis. We report on pediatric ACT patients registered with the Malignant Endocrine Tumor studies and explore the EXPeRT recommendations for management. Patients: Data from the ACT patients (<18 years) were analyzed. For the risk prediction, the patients were retrospectively assigned to the COG stages and the five-item score. Results: By December 2021, 161 patients with ACT (ACA n = 51, ACx n = 19, and ACC n = 91) had been reported (the median age at the diagnosis was 4.3 years with a range of 0.1–17.8), with lymph node and distant metastases in 10.7% and 18.9% of the patients with ACC/ACx. The mean follow-up was 4.5 years (with a range of 0–16.7). The three-year overall (OS) and event-free survival (EFS) rates were 65.5% and 50.6%. In the univariate analyses, the OS was impaired for patients aged ≥ 4 years (p = 0.001) with the initial biopsy (p = 0.016), tumor spillage (p = 0.028), incomplete tumor resection (p < 0.001), unfavorable histology (p = 0.047), and COG stages III/IV (p = 0.002). Multivariate analysis revealed COG stages III/IV and an unfavorable five-item score as independent negative prognostic factors for the EFS and OS. Conclusions: Age defines the clinical presentation and prognosis in pediatric ACTs. The outcome is best predicted by the COG stage and five-item score.

Paediatric appendiceal neuroendocrine tumours (appNET) are very rare tumours, mostly detected incidentally by histopathological evaluation after appendectomy. Treatment recommendations are based on adult data considering high-risk NET as defined by European Neuroendocrine Tumour Society (ENETS) guidelines for completion right-sided hemicolectomy (RHC). Recent data suggest that less aggressive therapy may be justified. Analysis of children and adolescents with appNET prospectively registered with the German Malignant Endocrine Tumour (MET) studies between 1997 and 2022. By December 2022, 662 patients (64.7% females, 35.3% male) had been reported. Median age was 13.3 years [4.5-17.9], median duration of follow-up 2.2 years [0-10.9]. No distant metastases were reported. Tumour size was 2 cm in 3.2% of patients. WHO grade 1 and 2 tumours were diagnosed in 76.9% and 23.1% of patients, respectively. Lymphovascular invasion and lymph node metastases were associated with tumour size ≥1.5 cm. 27.0% of patients presented with high-risk NET according to ENETS criteria. Of those, only 55.9% underwent secondary oncological right hemicolectomy. Neither distant metastases, nor recurrences or disease-related deaths occurred in patients with appendectomy only as well as in patients with completion RHC. Overall and event-free survival were both 100%. Internationally harmonized consensus recommendations on treatment of children and adolescents with appendiceal NET are urgently needed to avoid completion RHC in high-risk patients.

Background: Locally advanced tumors account for approximately 50% of children and adolescents with adrenocortical carcinoma (ACC), and of these, up to 50% relapse. We explored the five-item microscopic score and the pS-GRAS score for guiding management. Methods: Data from children and adolescents with COG stage II and III ACC registered in the MET studies were included. The five-item and pS-GRAS score were retrospectively calculated. Results: By December 2021, 55 patients with stage II and III (stage II n = 18, stage III n = 37) had been reported. Median age was 4.3 years [0.1–17.8], median duration of follow-up 6.0 years [0–16.7]. 3-year event-free survival (EFS) rate was 76.5% and 49.8% (p = 0.088), respectively. In stage II tumors, neither the five-item score (p = 0.872) nor pS-GRAS grouping (p = 0.218) had any effect as prognostic factors. In stage III patients, EFS was impaired in tumors with unfavorable histology according to the five-item score (100% vs. 30.8%, p = 0.018). No difference was observed for pS-GRAS groups (p = 0.798). Conclusions: In patients with COG stage III, but not stage II, the five-item score affected EFS. Further studies are needed to identify patients at risk in COG stage II.

Osteonecrosis (ON) is a debilitating side effect of anti-leukemic treatment. Thus far, the role of leukemic infiltration (LI) of bone is unclear. The first 30 children aged ≥10 years, who were enrolled in the ongoing OPAL trial and had MRI studies at diagnosis and at 6 months, were analyzed. MRI revealed extensive LIs in 24 (80%) patients. The signal abnormalities changed back to a physiological signal in 29 out of 30 children at 6 months. Of the 24 children with LIs at diagnosis, 3 (12.5%) developed ON ≥ II, whereas 4 (66.7%) patients without LIs subsequently developed ON ≥ II (p = .016). No differences between children initially presenting with/without LIs were observed concerning age, pubertal stage, white blood count, immunophenotype, and clinical presentation. Initial radiological LI of bone and, thus, single MRI at diagnosis cannot identify children at high risk of developing radiological ON at 6 months into treatment.

Context: Adrenocortical carcinomas are very rare malignancies in childhood associated with poor outcome in advanced disease. Most adrenocortical tumors (ACT) are functional, causing signs and symptoms of adrenal hormone excess. In most studies, endocrine manifestations were reported 4 to 6 months prior to diagnosis. Objective: We sought to extend knowledge on endocrine manifestations with regard to age and sex to facilitate early diagnosis. Methods: We retrospectively analyzed features of adrenal hormone excess in children and adolescents with ACT registered with the GPOH-MET studies between 1997 and 2022. Stage of puberty was defined as prepubertal in females < 8 years of age and males < 9 years. Results: By December 2022, 155 patients (110 female, 45 male) with data on endocrine manifestations had been reported. Median age at ACT diagnosis was 4.2 years [0.1-17.8], median interval from first symptoms was 4.2 months [0-90.7]. In 63 girls of prepubertal age, the most frequently reported manifestations were pubarche (68.3%), clitoral hypertrophy (49.2%), and weight gain (31.7%); in 47 pubertal female patients, the most frequent manifestations were excessive pubic hair (46.8%), acne (36.2%), and hypertension (36.2%). Leading symptoms in 34 boys of prepubertal age were pubarche (55.9%), penile growth (47.1%), and acne (32.4%), while in 11 pubertal male patients, leading symptoms were weight gain (45.5%), hypertension (36.4%), excessive pubic hair (27.3%), and cushingoid appearance (27.3%). In pubertal patients, symptoms of androgen excess were mainly unrecognized as part of pubertal development, while symptoms of Cushing syndrome were more frequently apparent. Conclusion: The endocrine phenotype induced by pediatric ACT is age- and sex-dependent.

Context: Pediatric differentiated thyroid carcinoma (DTC) often presents with advanced disease but generally has excellent long-term survival. However, recurrence or failure to achieve remission remains relatively frequent, underscoring the need for improved early risk stratification. Objective: To develop and evaluate an interpretable machine learning model for predicting recurrence or nonremission in pediatric DTC using routine clinical and biochemical variables. Design and Setting: Retrospective analysis of 250 pediatric patients (aged <18 years) enrolled in the German Pediatric Oncology Hematology-Malignant Endocrine Tumors Registry (1997-2023). Inclusion required known age at diagnosis and ≥24 months of follow-up. The composite study endpoint was structural recurrence or failure to achieve remission within 24 months of initial therapy. Methods: An extreme gradient boosting classifier was trained on 80% of the data, with the remaining 20% used as an independent test set. Model generalizability was assessed via 50 randomized stratified train-validation splits of the training dataset. SHapley Additive exPlanations (SHAP) were used to interpret feature contributions. Results: The final model achieved an area under the receiver operating characteristic curve (AUROC) of 0.86 on the independent test set. Across 50 validation splits, the mean AUROC was 0.82 (SD ± 0.05), sensitivity 0.81 (SD ± 0.09), and specificity 0.64 (SD ± 0.06). SHAP analysis identified younger age at diagnosis (<10 years), elevated postoperative thyroglobulin levels, and distant metastases as the most influential predictors. Conclusion: This interpretable machine learning model reliably predicts early recurrence or nonremission in pediatric DTC and may complement current risk stratification systems to support personalized, risk-adapted treatment decisions.