Malignant triton tumor: A rare subtype of malignant peripheral nerve sheath tumor – A 20-year retrospective review

Background: Malignant triton tumor (MTT) is a rare and aggressive subtype of malignant peripheral nerve sheath tumor characterized by rhabdomyoblastic differentiation. Its diagnosis and management remain clinically challenging due to rarity and poor prognosis. Objectives: The objective of this study was to present a recurrent case of MTT and to review the clinicopathological characteristics of 10 additional cases from a single center over 20 years to better reveal the disease’s behavior and outcomes. Methods: We describe the clinical course of an 87-year-old woman with recurrent MTT of the back despite multimodal treatments and retrospectively reviewed patients diagnosed with MTT between 2005 and 2025. Inclusion required histopathologic confirmation with supportive immunohistochemistry. Clinical data, treatment, and outcomes were collected. Descriptive statistics and comparative analyses between neurofibromatosis type 1 (NF1) and non-NF1 cases were performed. Results: A total of 10 patients with MTT were identified, with a median age of 65 years. Three (30%) patients had NF1, two had radiotherapy-induced tumors, and most lesions (70%) measured >5 cm. The majority (79%) were Fédération Nationale des Centres de Lutte Contre le Cancer grade 3. Six patients underwent radical resection with negative margins, while four had intralesional excision. Adjuvant radiotherapy was given in nine patients and chemotherapy in five patients. Local recurrence occurred in 6 (60%) patients at a median of 6 months, and 2 (20%) patients developed lung metastases. At the last follow-up, 3 (30%) patients had died. Conclusion: MTT exhibits aggressive clinical behavior and high recurrence risk. Early diagnosis, wide-margin resection, and multidisciplinary management are essential. Broader data collection and long-term follow-up are needed to improve outcomes.