Unusual extramedullary relapses in a case of common B-cell acute lymphoblastic leukemia. Case report and review of literature.

Acute lymphoblastic leukemia (ALL) represents the most common malignancy in children with an overall cure rate of 85%. Relapses occur in 20% of the cases. Commonly, extramedullary relapses (EMRs) involve central nervous system (CNS) or testes. Unusual EMRs in ALL are relatively rare reported.The authors present a 24-year-old woman with ALL, who experienced three unusual EMRs. In 2007, she was diagnosed with B-cell precursor (BCP)-ALL - high-risk (HR) group, and she was treated according to ALL Intercontinental Berlin-Frankfurt-Münster (IC-BFM) 2002∕HR Protocol. She entered complete remission (CR). In 2012, a vaginal wall solid mass infiltrate occurs. Biopsy concluded for EMR of ALL. Chemotherapy was restarted; the patient responded again with CR. Magnetic resonance imaging (MRI) and positron emission tomography∕computed tomography (PET∕CT) examinations during follow-up revealed supraclavicular, mesenteric, and retroperitoneal lymphadenopathies (2014). Pathological examination of the supraclavicular lymph node showed a benign pattern: schwannoma. The patient's evolution worsened, imposing a biopsy from the retroperitoneal tumor which revealed a second EMR of ALL. Again, ALL-REZ BFM 2002 Protocol was started, followed by haploidentical mother-to-child peripheral blood hematopoietic stem cell transplantation (HSCT). After suffering a few managed complications related to the transplant, our patient achieved CR again. In 2017, 10 years after the initial diagnosis, the patient presented for the third time an EMR (gastric wall) and eventually died due to progression of the disease.The patient presented an extremely aggressive type of ALL with three unusual EMRs: vaginal, retroperitoneal and gastric.