Pediatric Precursor B-Cell Lymphoblastic Malignancies: From Extramedullary to Medullary Involvement
Emma Kroeze, Laura Padilla, Max Bakker, Judith M. Boer, Melanie M. Hagleitner, Birgit Burkhardt, Takeshi Mori, Andishe Attarbaschi, Jaime Verdú‐Amorós, Marta Pillon, Liliya Anderzhanova, Edita Kabíčková, Aks Chiang, Rejin Kebudi, Karin Mellgren, Jelena Lazić, Janez Jazbec, Jules P.P. Meijerink, Auke Beishuizen, Jan Loeffen
Abstract
B-cell lymphoblastic lymphoma (BCP-LBL) and B-cell acute lymphoblastic leukemia (BCP-ALL) are the malignant counterparts of immature B-cells. BCP-ALL is the most common hematological malignancy in childhood, while BCP-LBL accounts for only 1% of all hematological malignancies in children. Therefore, BCP-ALL has been well studied and treatment protocols have changed over the last decades, whereas treatment for BCP-LBL has stayed roughly the same. Clinical characteristics of 364 pediatric patients with precursor B-cell malignancies were studied, consisting of BCP-LBL (n = 210) and BCP-ALL (n = 154) patients. Our results indicate that based on the clinical presentation of disease, B-cell malignancies probably represent a spectrum ranging from complete isolated medullary disease to apparent complete extramedullary disease. Hepatosplenomegaly and peripheral blood involvement are the most important discriminators, as both seen in 80% and 95% of the BCP-ALL patients and in 2% of the BCP-LBL patients, respectively. In addition, we show that the overall survival rates in this cohort differ significantly between BCP-LBL and BCP-ALL patients aged 1−18 years (p = 0.0080), and that the outcome for infants (0−1 years) with BCP-LBL is significantly decreased compared to BCP-LBL patients of all other pediatric ages (p < 0.0001).