Methotrexate (MTX) intrathecal and intravenous administration is associated with neurotoxicity. We report a 15-year old girl diagnosed with large cell B lymphoma. On eighteen-day after intrathecal MTX presented stroke-like symptoms. Magnetic resonance was informed as a possible stroke in the right frontal lobe. The patient does not meet the criteria for fibrinolysis. MTX neurotoxicity was suspected, and theophylline was initiated. She showed complete recovery after three days of treatment. After describing the case, we review MTX neurotoxicity cases from our centre from January 2010 to December 2018. Also, we added to this data the previously published cases in the literature.

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.