In laymans terms, this refers to tumours that do not have the potential to jump elsewhere in your body (metastasize); will not come back once removed; and will not kill you. This is not to say they don’t cause symptoms; some can cause problems by virtue of their location e.g., a lipoma that presses on a nerve, or the way they grow eg a giant cell tumour weakening a bone such that it breaks (fractures).
Some of these benign tumours have the potential to later turn into malignant tumours, and so are often removed before they cause any symptoms at all eg some lipomas, some osteochondromas.
Dr Shooter is very aware that it can be incredibly traumatic to be diagnosed with any tumour, benign or not, and is always happy to discuss removal of benign lumps or bumps “just because”.
A few common benign tumours
A benign tumour of fat. One of the commonest soft tissue tumours. Can occur almost anywhere in the body. Symptoms usually related to size or location; most are an incidental finding. True lipomas do not undergo malignant transformation; the problem is that it can be very difficult to differentiate a large true lipoma (completely benign) from an atypical lipoma (risk of malignant transformation), or even a low-grade liposarcoma (malignant). Usually recommend excision.
- Osteochondroma / exostosis
A benign tumour of cartilage; normal cartilage growing from bone. One of the commonest tumours arising from bone. Usually around the knee or shoulder; 90% solitary. Essentially a “growth mistake”, and stops growing when the child stops growing. Symptoms from cosmesis or location eg muscle rubbing over the lump or “tenting” the skin. Less than 1% risk of malignant transformation (to chondrosarcoma). Risk higher in the genetic condition of multiple hereditary exostosis. Usually recommend excision if symptomatic.
Another common benign tumour of cartilage; another “growth mistake” where normal cartilage grows inside a normal bone. Most are incidental findings. Low risk of malignant transformation. Treated with observation; if painful can be curetted and grafted (scraped out and the resulting hole filled with bone graft).
- Pigmented villonodular synovitis (PVNS)
The lining of joints, usually the knee (also hip and ankle), overgrows. Can be 1-2 solitary nodules, or involve the entire lining of the joint. Mechanical symptoms from the extra tissue; pain and/or instability. No malignant potential recognised. Mainstay of treatment is surgical excision; radiation therapy being trialled in some centres. High risk of recurrence after surgery.
- Giant cell tumour of bone
Normal bone cells replaced by cells that “eat” bone; causing mechanical weakening – pain, risk of fracture. Fifty per cent occur around the knee. Treated with curettage and grafting; extremely high risk of recurrence. May need megaprosthetic replacement in recurrences.
Catch-all phrase for small, fluid-filled lumps that arise from joints or tendons. Classically around the wrist; a Baker’s cyst is an example from the knee. These are not tumours per se, but represent the body’s reaction to damage eg torn meniscus in the knee, overuse injuries of the wrist. Treatment is excision if troublesome; small but real risk of recurrence (as excising doesn’t treat the underlying problem).