Malignant triton tumor: 2 sporadic cases and review

Abstract

<h3>Background</h3> Malignant peripheral nerve sheath tumors (MPNST) are rare sarcomas commonly associated with neurofibromatosis. When MPNST coexists with rhabdomyoblasts: these lesions are termed malignant triton tumor (MTT); a subgroup of exceedingly rare, highly aggressive soft tissue tumors. <h3>Methods</h3> Two index cases of MTT. Case #1: An 80-year-old female presented with a right buttock mass. A 28 cm lobulated soft-tissue tumor arising from the sciatic nerve was excised. Case #2: A CT scan of a 27-year-old female with nasal polyps revealed opacification of the left nasal passage and maxillary, ethmoid, and frontal sinuses by a large mass that was excised. A 15-year retrospective surgical pathology review identified 21 cases of MPNST with six (29%) exhibiting transition from a neurofibroma. <h3>Results</h3> Histopathological examination of Cases #1 and #2 revealed the presence of SI00 positive pleomorphic spindle cell sarcoma admixed with plump strap/oval cells with linear striations and intense desmin reactivity on immunohistochemical staining confirming the diagnosis of malignant triton tumor. Both cases were not associated with neurofibromatosis-1. <h3>Conclusions</h3> Sporadic MTT is an extremely uncommon soft tissue tumor. Given the aggressive clinical course of such tumors, early and accurate diagnosis is critical for best patient management as complete tumor resection may improve patient survival.