Malignant triton tumor in the setting of segmental neurofibromatosis: A rare case report and review of the literature

Abstract Introduction Malignant triton tumors (MTTs) are a rare and highly aggressive subtype of malignant peripheral nerve sheath tumors (MPNSTs) displaying rhabdomyoblastic differentiation. Similarly, segmental neurofibromatosis (SN) is a rare subtype of neurofibromatosis (NF), a condition predisposing patients to MPNSTs and MTTs. Few reports have documented MTTs in the setting of NF, and none have detailed its occurrence in SN. Here, we describe such a case, its management, and cytogenetic analysis in the context of literature review. Case A healthy 25-year old female presented with a 1.5-year history of left anteromedial thigh pain, sensory deficit, and growth of a palpable mass prompting magnetic resonance imaging at an outside hospital. The patient underwent initial intralesional resection, however upon diagnosis of MTT, the patient was referred to the peripheral nerve service at our institution. On examination, the patient was found to have asymmetric inguinal freckling and multiple cafe-au-lait spots isolated to the extremity, in addition to leg extension weakness. After negative metastatic staging and repeat imaging showing residual/recurrent tumor, the patient was taken back for an en-bloc resection. Cytogenetic profiling revealed gene mutation to NF, TP53, CDKN2A/B, EED and a myriad of large structural chromosomal abnormalities. Despite completing an en-bloc resection with negative margins, the patient had another recurrence requiring a third resection. At last follow-up, the patient was doing clinically well with some persistent weakness, and was undergoing postoperative radiotherapy. Conclusion MTTs represent a rare subset of MPNST, not previously detailed in a SN patient. Given their poor overall prognosis, early clinical and radiological follow-up is necessary for these patients due to MTT tendency to recur early and metastasize.