Malignant triton tumor (MTT) is a very infrequent variant of the malignant peripheral nerve sheath tumor (MPNST) with rhabdomyoblastic differentiation. Up to 70% of cases are diagnosed in patients with neurofibromatosis type 1 (NF1). It is a highly aggressive pathology with early relapses occurring in up to 50% of patients. Despite multimodal treatment the prognosis is poor, with long term survival rates not exceeding 15%. We present the case of an adolescent male with known NF1 diagnosed with an aggressive retroperitoneal MTT and disseminated pulmonary disease.

Primary bone composite sarcoma is a very rare entity that primarily affects adolescent and young adult patients. It usually combines areas of liposarcoma and osteosarcoma and up to 60% of cases have metastatic disease at diagnosis. It is a highly aggressive pathology with intrinsic resistance to conventional treatment schemes for bone sarcomas. The prognosis is poor, with long term survival rates that do not exceed 30%. We present the case of an adolescent female diagnosed with a primary agressive bone composite sarcoma with rhabdomyosarcoma foci and loco-regional lymph node involvement.