Mesoblastic nephroma is the most frequent renal tumor in newborns and young infants, and the cellular type is characterized by an ETV6–NTRK fusion, which constitutively activates the tropomyosin‐related kinase (TRK) signaling pathway. Larotrectinib is a highly selective TRK inhibitor with activity in adult and pediatric patients who have TRK fusions. We present a rare case of a patient with mesoblastic nephroma metastatic to bone who had a dramatic response to larotrectinib.

Germline TP53 splicing variants are uncommon, and their clinical relevance is unknown. However, splice-altering variants at exon 4–intron 4 junctions are relatively enriched in pediatric adrenocortical tumors (ACT). Nevertheless, family histories of cancer compatible with classic Li-Fraumeni syndrome are rarely seen in these patients. We used conventional and in silico assays to determine protein stability, splicing, and transcriptional activity of 10 TP53 variants at exon 4–intron 4 junctions and analyzed their clinical correlates. We reviewed public databases that report the impact of TP53 variants in human cancer and examined individual reports, focusing on family history of cancer. TP53 exon 4–intron 4 junction germline variants were identified in 9 of 75 pediatric ACTs enrolled in the International Pediatric Adrenocortical Tumor Registry and Children's Oncology Group ARAR0332 study. An additional eight independent TP53 variants involving exon 4 splicing were identified in the Pediatric Cancer Genome Project (n = 5,213). These variants resulted in improper expression due to ineffective splicing, protein instability, altered subcellular localization, and loss of function. Clinical case review of carriers of TP53 exon 4–intron 4 junction variants revealed a high incidence of pediatric ACTs and atypical tumor types not consistent with classic Li-Fraumeni syndrome. Germline variants involving TP53 exon 4–intron 4 junctions are frequent in ACT and rare in other pediatric tumors. The collective impact of these germline TP53 variants on the fidelity of splicing, protein structure, and function must be considered in evaluating cancer susceptibility. Implications: Taken together, the data indicate that splice variants at TP53 codon 125 and surrounding bases differentially impacted p53 gene expression and function.

Background: This study compares the outcomes of managing retinoblastoma between patients with unilateral and bilateral presentations. Methods: The study, conducted at the King Hussein Cancer Center in Amman, Jordan, retrospectively analyzed cases of retinoblastoma treated between March 2003 and December 2019. Evaluation criteria included clinical features, disease stage, treatment methods, and overall management outcomes. Results: The study comprised 697 eyes from 478 patients with retinoblastoma, with 52% being males. Bilateral disease was observed in 70% of patients, and a family history of retinoblastoma was more prevalent in cases with bilateral disease (20%) compared to those with unilateral disease (4%). Unilateral cases had a median age at diagnosis of 28 months, whereas bilateral cases were diagnosed at a median age of 6 months. Extra-ocular retinoblastoma was detected in 1% of eyes. According to the International Intraocular Retinoblastoma Classification (IIRC), 88% of unilateral cases presented with advanced disease (IIRC group D/E), compared to 46% in bilateral cases. Primary enucleation was performed in 29% of unilateral cases and 16% of bilateral cases (p-value 0.0007). Eye salvage rates were 31% in unilateral cases and 68% in bilateral cases (p-value < 0.0001). At 120 months of follow-up, 5% of patients died from secondary neoplasms or metastases, 81% were alive, and 14% were lost to follow-up. There was no significant difference in metastasis, secondary neoplasms, or mortality between patients with unilateral and bilateral retinoblastoma. Conclusions: This study highlights the nuanced differences in clinical characteristics and outcomes between unilateral and bilateral retinoblastoma, emphasizing the necessity of customized management and early detection strategies. It demonstrates that while bilateral retinoblastoma benefits from earlier detection and has a higher rate of eye salvage, there is no significant difference in metastasis or mortality rates when compared to unilateral cases. The critical roles of primary enucleation in advanced cases, along with effective communication and patient education, are also underscored to improve treatment adherence. Overall, these findings point to the importance of tailored approaches in optimizing outcomes for the diverse patient population affected by retinoblastoma.

Aim: To compare the risk and pattern of High-Risk Pathologic Features (HRPF) in retinoblastoma between primary and secondary enucleation. Methods: A retrospective analysis of 121 eyes from 118 patients who underwent enucleation at the King Hussein Cancer Center (KHCC) Amman, Jordan, between November 2009 and January 2020. Demographic information, tumor stage, time from diagnosis–to-enucleation, results of pathology, metastasis, and mortality were retrieved. Results: Patients in the secondary group (49/121 eyes, 40%) were considerably younger at diagnosis (p = 0.0014), had bilateral disease (p = 0.0001), and had less-progressed disease at presentation (p = 0.016) compared to the primary enucleation. Primarily enucleated eyes were more-likely to have massive choroidal invasion (p = 0.0315) and post-laminar optic nerve invasion (p = 0.027), in spite of the finding that the overall prevalence of HRPF was similar between the two groups (35.5 percent vs. 37.5 percent; p = 0.585). The likelihood of anterior chamber invasion, was considerably higher in secondary enucleated eyes (p = 0.013). We evaluated primary and secondary enucleation for each subgroup (D and E) of the International Intraocular Retinoblastoma Classification (IIRC) and found the prevalence of HRPF was comparable (p = 0.58, 1.0, respectively). The difference in time between diagnosis-to-enucleation in secondary enucleation did not predict HRPF (p = 0.50). There was no discernible difference between primary and secondary enucleated eyes in terms of metastasis or survival (p = 0.156 and 0.44, respectively). Conclusion: Systemic chemotherapy has the ability to reduce the extent of tumor expansion that has been pathologically identified. Primary and secondary enucleated eyes are comparable in low metastatic risk only when strict examination and management guidelines are followed.