Fusion-negative rhabdomyosarcoma with diffuse bony metastases and remarkable chemosensitivity.

In this report, we describe the case of an adolescent male with an unusual case of fusion-negative, paratesticular alveolar rhabdomyosarcoma who presented with spontaneous tumour lysis syndrome and diffuse bony metastases throughout the axial and appendicular skeleton with additional significant bone marrow involvement. Both spontaneous tumour lysis syndrome and diffuse bony metastases are extremely unusual for rhabdomyosarcoma. On the backbone of standard vincristine, dactinomycin and cyclophosphamide (VAC) chemotherapy, the only local control was orchiectomy at 15 weeks, with no radiation administered due to the initially diffuse nature of the disease and rapid response to chemotherapy. Following 43 weeks of VAC, a year-long maintenance phase with pazopanib was given which was well tolerated. The patient remains in remission now 4 years after completion of therapy.