Malignant triton tumor of the bladder with fatal outcome: a rare case report.

Malignant triton tumors (MTTs) are a rare subtype of malignant peripheral nerve sheath tumors characterized by rhabdomyoblastic differentiation, often associated with neurofibromatosis type 1 (NF-1). Primary MTTs of the bladder are exceptionally uncommon, with few documented cases. We report a case of a 75-year-old male without neurofibromatosis type 1 history presenting with hematuria and urinary obstruction. Imaging revealed a 6.5 × 4 × 2 cm invasive bladder mass, and histopathology confirmed a high-grade spindle cell neoplasm with biphasic neurogenic (S100-positive) and rhabdomyoblastic (desmin- and myogenin-positive) differentiation, consistent with a diagnosis of MTT. Despite radical cystoprostatectomy, the patient succumbed to postoperative complications. This case highlights the aggressive behavior, diagnostic challenges, and poor prognosis of bladder MTTs, emphasizing the critical role of immunohistochemistry in distinguishing them from other spindle cell neoplasms. The rarity of this presentation underscores the need for further research to elucidate its pathogenesis and optimize therapeutic strategies.