[Retroperitoneal malignant peripheral nerve sheath tumor a preschool child].

Background: Malignant tumors of peripheral nerve sheath (MPNSTs for its acronym in English) are aggressive sarcomas that occur generally in adulthood and are located mainly on the trunk and lower limbs, with a high association with neurofibromatosis type 1 (NF1).

Case Report: A 34-months-old female infant without NF1 with a palpable abdominal mass is described. The mass corresponded to a retroperitoneal MPNST.