Malignant mesenchymoma of ulnar nerve: combined sarcoma of nerve sheath and rhabdomyosarcoma.

Abstract

SUMMARY Malignant mesenchymoma within the right ulnar nerve of an 8 year old boy is described. The patient did not have stigmata of von Recklinghausen's neurofibromatosis. The growing and painful tumour was excised five and a half months after detection, and recurred five months later. Mingling of the nerve sheath sarcoma and rhabdomyosarcoma was noted within the same mass which was separated from the adjacent striated muscles. It is suggested that this mesenchymoma arose from mesenchymal cells or cells of mesenchymal type comprising the peripheral nerve sheath which is derived from ectomesenchyme of the neural crest.We have already recorded two cases of primary intracranial rhabdomyosarcoma (Shuangshoti et al, 1968;Shuangshoti and Phonprasert, 1976). This tumour comprised only 0.1 % of 1028 intracranial neoplasms reported by Shuangshoti and Panyathanya (1974). These authors have also investigated 1274 tumours of peripheral nerve-61.5 % neurofibromas, 33.5 % neurilemmomas, 0.1 % combined neurofibromas and neurilemmomas, and 4.9 % nerve sheath sarcomas (so-called malignant Schwannomas, neurofibrosarcomas, or neurogenic sarcomas). They found no instances of these peripheral nerve neoplasms containing elements of striated muscle. Only a subcutaneous neurilemmoma had bone formation within the mass which was presented separately

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

“…We suggest the neural crest, an ectomesenchymal structure [ 11,14,22], as the origin of our patient's median nerve malignant mesenchymoma. Aberrant differentiation of mesenchymal elements of the neural crest into malignant fibroblasts, Schwann cells, and adipose tissue would create a mixed nerve sheath sarcoma and liposarcoma.…”

“…The diagnosis of malignant mesenchymoma is most appropriate in the present case because of the diversity in types of the tumor cells within the mesenchymal line [9,11]. This diagnosis is regarded as equivalent to "mixed sarcoma" of nerve sheath origin.…”

“…Aberrant differentiation of mesenchymal elements of the neural crest into malignant fibroblasts, Schwann cells, and adipose tissue would create a mixed nerve sheath sarcoma and liposarcoma. The Schwann cell as a mesenchymal-type cell has been discussed [4, 11,14]. Neuroepithelial tumors would be formed when the ectodermal part of the neural crest becomes neoplastic.…”

“…Survey of the literature discloses that peripheral nerve tumors may show, in addition to Schwann cells and fibroblasts, such diverse elements as osteoid [ 1,2], bone [3,4], rosette formation [ 1 3 , glandular structure [6,7], chondrosarcoma [8], rhabdomyosarcoma [8,11], angiosacoma [ 121, and liposarcoma [ 131. We record herein a neoplasm of the median nerve consisting of sarcoma of the nerve sheath cells and liposarcoma representing a malignant mesenchymoma.…”