Malignant neoplasm of mixed mesenchymal and neuroepithelial origin (ectomesenchymoma) of thigh

Abstract

A 49-year-old man had a malignant soft tissue tumor of the right thigh with metastasis to the femoral region and lower quadrant of the anterior abdominal wall on the right side and the left supraclavicular lymph nodes. The neoplasm showed features of chondrosarcoma and primitive neuroectodermal tumor (combined neuroblastoma, ependymoma, astrocytoma, and oligodendroglioma). The gliomatous part of the mixed tumor was confirmed by identification of the glial fibrillary acidic protein (GFAP). The diverse cellular population suggests a tumor origin from the ectomesenchymal remnant of the neural crest. The mesenchymal component of the neural crest would differentiate into the chondrosarcoma and the neuroectodermal component into the primitive neuroectodermal neoplasm. These various neoplastic elements, then, would form a neoplasm of mixed mesenchymal and neuroepithelial origin or an ectomesenchymoma.

Malignant Ectomesenchymoma

“…The mainly differential diagnosis [23, 24, 26, 27, 31, 33, 34, 36]of ectomesenchymoma includes teratoma, Wilm’s tumor, benign and malignant triton tumors, and other collision tumors. The factors that make these tumors unlike ectomesenchymoma are described in table 2.…”

“…Malignant ectomesenchymoma is a rare tumor of soft tissues or the CNS, which is composed of both neuroectodermal elements [represented by ganglion cells and/or well-differentiated or poorly differentiated neuroblastic cells such as ganglioneuroma, ganglioneuroblastoma, neuroblastoma, peripheral primitive neuroectodermal tumors (PNET)] and one or more mesenchymal neoplastic elements, usually rhabdomyosarcoma [22, 23, 24, 25, 26, 27]. The most accepted theory suggests that this tumor arises from remnants of migratory neural crest cells and thus from the ectomesenchyme [22, 23, 25, 28, 29, 30, 31, 32, 33].…”

Primitive neuroectodermal (neuroepithelial) tumour of soft tissue of the neck in a child: demonstration of neuronal and neuroglial differentiation

“…The perikaryon, moreover, was GFAP positive (Figure 4) as was that of the astrocytic tumour cells serving as a control. These neoplastic cells were considered to be astrocytic (Shuangshoti & O'Charoen 1983, Shuangshoti et al 1984, Shuangshoti 1986). Some plump astrocytes resembled neurons in H & E preparations but they could be distinguished immunohistochemically from ganglion cells by localization of cytoplasmic GFAP.…”

“…We have described mesenchymal tumours of the peripheral nerves such as neurilemmomas, neurofibromas, and sarcomas of the nerve sheath (Shuangshoti & Netsky 1971, Shuangshoti & Panyathanya 1974, Cutchavaree, Shuangshoti & Kumut 1984a, b, Cutchavaree et al 1984, and malignant mesenchymomas (Shuangshoti & Chongchet 1979, Shuangshoti, Benjavongkulchai & Chittmittrapap 1984. Examples of combined mesenchymal and neuroepithelial tumours of peripheral nerves include parapharyngeal neoplasm of mixed sarcoma of the nerve sheath, meningioma with an osseous component, rhabdomyosarcoma and ganglioneuroma (Shuangshoti & Cutchavaree 1980), chondrosarcoma combined with primitive neuroectodermal tumour (neuroblastoma, ependymoma, astrocytoma, and oligodendroglioma) and malignant ectomesenchymoma of the soft tissues of the thigh (Shuangshoti et al 1984). In this communication, an extremely rare, primitive neuroectodermal tumour arising in the soft tissue of the neck of a child is presented.…”

Malignant ectomesenchymoma of the nasal cavity

“…Different therapeutic approaches have been reported in published studies, especially for cases affecting adults. [6–8] Our patient has completed radiotherapy and 42 weeks of chemotherapy and is in remission.…”