Abstract
Background: Malignant Triton Tumor (MTT) constitutes a subtype of Malignant Peripheral Nerve Sheath Tumor, whose retroperitoneal localization is extremely rare: at this time, only some twenty cases reports have been reported since its first description. We present the case of a MTT diagnosed on the histological examination after the mass resection, which was previously considered as myxofibrosarcoma according to biopsy findings.
Case presentation: A 76-year-old woman suffered from femoral pains resulting from a left retroperitoneal mass, 33cm in diameter, arising from the major psoas muscle. In view of the so-called diagnosis and the age, we decided to perform an up-front R1 left compartmentectomy sparing pancreas without neoadjuvant treatment. The tumor was found to involve the femoral trunk nerve, necessitating its resection so that the piece remains unfragmented. Immunohistochemical analysis finally revealed a MTT with a focal positivity for S100, as well as a focal staining with markers of skeletal muscle differentiation. The postoperative course was uneventful besides the foreseeable femoral paralysis, and adjuvant irradiation was proposed.
Tumor heterogeneity can explain the discrepancy between the settings of the core needle biopsy and the definitive histological conclusions, and highlights the difficulty bringing the correct diagnosis with a biopsy alone. Nevertheless, according to the acknowledged poor prognosis, the risk-benefit balance in this particular context should have discouraged a wider resection even if MTT was diagnosed before surgery.
Conclusions: This case report raises the question of the major place of geriatric preoperative assessment and the appropriateness of multi-organs removals in elder patients, more specifically in those presenting aggressive sarcomas such as MTT.