Soft-tissue sarcoma
A soft-tissue sarcoma is a tumour that develops from muscle or soft tissue. These are sometimes called malignant mesenchymal tumours.
Rhabdomyosarcoma is the most common type of soft-tissue sarcoma in childhood. This is a cancer of primitive muscle cells and can develop anywhere in the body. The most common sites are around the head and neck, bladder, or testes in boys.
Who gets soft-tissue sarcoma?
About 60 children develop a soft-tissue sarcoma in the UK each year. It is slightly more common in boys than girls. About two-thirds of rhabdomyosarcomas occur in children under six years of age.
The cause of soft-tissue sarcomas is unknown. There may be genetic factors in some children, for example, those with Li Fraumeni syndrome, have an increased risk of developing rhabdomyosarcoma.
Signs and symptoms
The signs and symptoms will depend on where the tumour develops. The most usual sign is a swelling or lump. Other symptoms may include:
| Site of tumour |
Signs and symptoms |
| Head and neck area |
Blocked nose or discharge |
| Eye muscles |
Swollen or protruding eye |
| Tummy (abdomen) |
Swelling, discomfort or difficulty going to the toilet (constipation) |
| Bladder |
Blood in the urine or difficulty passing urine |
Tests / investigations
We will need to carry out some tests to find out as much as possible about the type position and size of the tumour. These tests include:
- Chest X-ray – to see whether the tumour has spread to the lungs.
- Ultrasound scan – this will tell us the position and size of the tumour.
- CT scan or MRI scan – a scan of the affected tissue and chest will be carried out. This will give us more information about the tumour and whether it has spread.
- Biopsy – this is a small operation, usually under general anaesthetic, to remove some tissue.
- Bone marrow aspirate and trephine – these tests will tell us whether the tumour has spread to the bone marrow.
Staging
Staging refers to the size of the tumour and whether it has spread. Knowing the stage of the cancer helps the doctors decide on the most appropriate treatment for your child. We use TNM (tumour, node, metastases) staging for soft-tissue tumours with a simplified version as follows:
- Stage I: Tumour confined to the organ or tissue of origin with no evidence of lymph node involvement or distant spread (metastases).
- Stage II: Tumour involving one or more adjacent organs or tissues, a collection of fluid (malignant effusion) or multiple tumours in the same organ, with no evidence of lymph node involvement or distant metastases.
- Stage III: Any of the above with lymph node involvement.
- Stage IV: Evidence of distant metastases.