Introduction:
Malignant triton tumor (MTT) is a very rare variant of the malignant peripheral nerve sheath tumor (MPNST), with rhabdomyoblastic differentiation, which primarily affects young adult patients (1-3). Up to 70% of cases are diagnosed in patients with neurofibromatosis type 1 (NF1), although sporadic and radiotherapy related cases have been also described (1-6). Clinical course is highly aggressive, with relapses occurring in up to 50% of patients. The prognosis is very poor and, with multimodal treatment, reported 5-year survival rates do not exceed 15% (1-3).
We present the case of an adolescent male with known NF1 diagnosed with an aggressive retroperitoneal MTT and disseminated pulmonary disease.