Malignant mesenchymoma of median nerve: Combined nerve sheath sarcoma and liposarcoma

Abstract

A malignant mesenchymoma consisting of nerve sheath sarcoma and liposarcoma occurred in the right median nerve of a 29-year-old man who did not have stigmata of von Recklinghausen neurofibromatosis. It produced pain at the affected part, referred pain to the palm, and weakness of muscles supplied by branches of this nerve. The tumor was first excised 1 month after its initial manifestation, but recurred twice and eventually metastasized to the lung within 19 months. It is suggested that aberrant differentiation of the mesenchymal component of the neural crest, the ectomesenchymal structure, has created this combined sarcoma of nerve sheath and liposarcoma, forming a malignant mesenchymoma.

Malignant Peripheral Nerve Sheath Tumors: Differentiation Patterns and Immunohistochemical Features - A Mini-Review and Our New Findings

“…Epithelioid or other heterogeneous components can be observed in 15% of MPNSTs 1, 2, 6: the latter include rhabdomyoblasts 1, 2, 6-12, cartilaginous 6, 13, 14, osseous 6, 12, 13 differentiations and, rarely, smooth muscle 13, 15, glandular 6, 10-12, 16 or liposarcomatous components 6, 12, 17 have been reported. It is rare that there are two or more heterogeneous components in a single MPNST.…”

“…The most common heterologous component in MPNST is rhabdomyoblast differentiation 1, 7, 8, being first reported by Masson in 1932 and named "nerve rhabdomyoma", and later renamed by Woodruff as "malignant triton tumor". Additionally, differentiation into cartilage or bone is also not uncommon 6, 12-14, while liposarcomatous differentiation is very rare; to date, only 4 cases have been reported 6, 12, 17. MPNST also has glandular structures 1, 2, 6, 10-12, 16, and foci of neuroendocrine differentiation are often seen in glandular MPNST 1.…”