Ectomesenchymoma is a rare, fast-growing tumor of the nervous system or soft tissue that occurs mainly in children, although cases have been reported in patients up to age 60.
Malignant ectomesenchymoma (MEM) 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 .
[2] The tumor largely affects children under 15 years of age and about 20% only are found in adults with nearly 60% involving males and 40% females (1).
The most frequent locations are head and neck (orbit and nasopharynx), central nervous system, abdomen and retroperitoneum, pelvis, perineum, scrotum and prostate(1).
Rhabdomyoblasts and poorly differentiated small cells display positivity for desmin and myosin while neural areas are variably sensitive to S-100.
Floris et al. found in their reported case hyperploidism in a subset of cells as well as gains of chromosomes 2, 11 and 20, a finding in common with alveolar rhabdomyosarcoma.
Kosem et al. collected 44 cases of MEM in a 2004 review and examined management data finding out that resection with pre- or post-surgery chemotherapy yielded the best results with one death only in 13.
In the five cases reported by Mouton et al. an aggressive chemotherapy and adequate surgical excision granted a disease-free interval for 7 to 50 months.
A malignant tumor of migratory neural crest (ectomesenchyme) remnants showing ganglionic, schwannian, melanocytic and rhabdomyoblastic differentiation.
Goldsby RE, Bruggers CS, Brothman AR, Sorensen PH, Beckwith JB, Pysher TJ (1998) Spindle cell sarcoma of the kidney with ganglionic elements (Malignant ectomesenchymoma) associated with chromosomal abnormalities and a review of the literature.
Floris G, Debiec-Rychter M, Wozniak KA, Magrini S, Maffioletti G, De Wever I, Tellini G, Sciot R (2007) Malignant ectomesenchymoma: genetic profile reflects rhabdomyosarcomatous differentiation.
Mouton SC, Rosenberg HS, Cohen MC, Drut R, Emms M, Kaschula RO (1996) Malignant ectomesenchymoma in childhood.