Ectomesenchymoma
Synonyms: Malignant Ectomesenchymoma (MEM), Gangliorhabdomyosarcoma
Mixed neural and rhabdomyoblastic tumour
Quick Facts
Behaviour
Malignant
Category
Soft tissue
Grade
High
Synonyms
- Malignant Ectomesenchymoma (MEM)
- Gangliorhabdomyosarcoma
Category
Soft tissue
Behaviour
Malignant
Grade
High
Gender
Male (1.5:1)
Tissue of Origin
Neural crest
Epidemiology
- Extremely rare (less than 100 cases reported)
- Children and adolescents most commonly affected
Clinical Features
- Rapidly enlarging soft tissue mass
- Aggressive clinical behaviour
Location
- Head and neck
- Abdomen
- Perineum
Imaging
MRI: large heterogeneous mass, areas of necrosis or haemorrhage. Low T1 and high T2 signal with vivid enhancement
Pathology
Biphasic appearance: Nests of small round blue cells interspersed with ganglion cells or primitive neuroectodermal cells
Genetics
Highly variable; can involve DICER1 mutations or translocations associated with rhabdomyosarcoma
Treatment
- Multiagent chemotherapy (rhabdomyosarcoma protocols)
- Wide surgical resection
- Radiotherapy
Prognosis
- Poor - 5-year survival 25-40%
- Limited data due to rarity
Key Points
- Mixed neural and rhabdomyoblastic tumour
- Children most affected
- Treated like high-grade rhabdomyosarcoma
Workup - Blood Tests
- FBC, U&E, LFTs
- LDH - prognostic marker
Workup - Local Imaging
MRI with contrast of primary site
Workup - Biopsy
- Core needle biopsy
- Extensive IHC panel
Workup - Staging
- CT chest
- PET-CT
- May require bone marrow aspirate
Follow-up Summary
Medical disclaimer
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