Elif Yüksel

Adenosine deaminase deficiency causes severe combined immunodeficiency, affecting T and B cells and increasing the risk of infections, immune dysregulation, and malignancy. Undifferentiated embryonal sarcoma of the liver is a rare pediatric mesenchymal tumor. We report a 7-year-old boy with adenosine deaminase deficiency presenting with fever, elevated acute phase reactants, and an 85 × 60 mm ² heterogeneous cystic liver mass on ultrasonography. Magnetic resonance imaging revealed a second nodule in segments 5 and 6. An abscess was initially suspected, but biopsy confirmed undifferentiated embryonal sarcoma of the liver. After chemotherapy, the patient underwent a left lobectomy and wedge resections. Histology showed complete necrosis of the sarcoma; however, a second tumor—fibrolamellar hepatocellular carcinoma—was identified. While immunodeficiencies are associated with lymphoproliferative disorders and malignancies, the link between adenosine deaminase deficiency and hepatic tumors is unclear. This patient's presentation highlights the potential for multiple primary hepatic malignancies in immunodeficient patients and suggests a need for further investigation.

Background: Adrenocortical tumors (ACTs) are exceedingly rare in children. The Wieneke scoring system is commonly used for malignancy classification; however, the prognostic role of immune checkpoint markers, particularly programmed death-ligand 1 (PD-L1), remains uncertain. Given the emerging role of immune checkpoints in cancer progression, this study evaluates PD-L1 expression in pediatric ACTs and its correlation with clinical outcomes. Procedure: A retrospective review was conducted on 23 pediatric ACT patients diagnosed between 2000 and 2020. Clinical, pathological, and immunohistochemical data were analyzed. Tumor samples were stained for PD-L1 using immunohistochemistry, with a positivity threshold set at ≥3%. Malignancy classification was performed using the Wieneke scoring system, and correlations between PD-L1 expression, malignancy classification, and patient outcomes were assessed. Results: Among the 23 patients, 12 had adrenocortical carcinoma (ACC) and 11 had adrenocortical adenoma (ACA). PD-L1 positivity was observed in three patients: one with ACA and two with ACC. One patient demonstrated PD-L1 positivity in both primary and metastatic tumor samples. Wieneke scoring classified 11 patients as malignant, one as intermediate, and 11 as benign. No significant correlation was found between PD-L1 expression and Wieneke scores. Conclusions: Although PD-L1 expression was more frequent in ACC cases, it did not demonstrate a significant prognostic impact. This finding aligns with broader variations in PD-L1 significance across different cancers. While immune checkpoint markers are implicated in tumor progression, their role in pediatric ACT remains unclear. Further multi-center studies are required to determine their prognostic relevance and therapeutic potential, particularly in the context of immunotherapy.