Adamantinoma-like Ewings Sarcoma
Treated the same as Ewing's sarcoma
Quick Facts
Behaviour
Malignant
Category
Bone and Soft tissue
Grade
High
Category
Bone and Soft tissue
Behaviour
Malignant
Grade
High
Gender
Female
Tissue of Origin
Mesenchymal with aberrant epithelial differentiation
Epidemiology
- Extremely rare
- Peak 2nd–3rd decades
Clinical Features
- Rapidly growing, painful mass
- Systemic symptoms may be present if metastatic
Location
- Head and neck (salivary glands, thyroid, neck)
- Long bones
- Pelvis
Imaging
- Plain radiograph: agressive osteolyitic '"moth-eaten'" lesion with periosteal reaction
- MRI: Significant soft tissue component, low T1 signal, high T2 signal
Pathology
- Small round blue cells arranged in nests or lobules
- Prominent squamous differentiation, keratin pearls, and strong Cytokeratin (CK) expression
Genetics
T(11;22)(q24;q12) translocation and EWSR1-FLI1 fusion (similar to classic Ewing Sarcoma)
Treatment
- Neoadjuvant chemotherapy (VDC/IE protocol)
- Wide surgical resection
- Adjuvant chemotherapy
- Radiotherapy if margins positive or unresectable
Prognosis
Localised disease 82% 5-year survival, 70% in regional spread and <40% in metastatic disease
Key Points
- Treated the same as Ewing's sarcoma
- Can be difficult to diagnose
- Crucial to distinguish from squamous cell carcinoma or true adamantinoma via molecular testing for EWSR1 rearrangements
Workup - Blood Tests
- FBC, U&E, LFTs - baseline and pre-chemo
- LDH and ALP - prognostic markers
Workup - Local Imaging
- Plain radiograph
- MRI with contrast of whole bone or primary site
Workup - Biopsy
- Core needle biopsy at sarcoma centre
- Extensive IHC panel to exclude other diagnoses
Workup - Staging
- CT chest
- Whole-body MRI or PET-CT
- Bone marrow trephine - prognostic
Follow-up Summary
Medical disclaimer
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