Benign tumours

A variety of benign tumours affects the hand. Some of the more important ones will be briefly described.

Giant cell tumour of tendon sheath
(pigmented villonodular synovitis or PVNS)

A slow growing soft growth usually adjacent to a joint in the finger but also elsewhere in the hand. It has an irregular slightly lumpy texture, and where overlying skin is thin it may show through as a patchy yellowy-brown structure. It tends to travel through areas of little resistence such as tendon sheaths and joints, and may appear in separate parts of the hand connected by such extensions. Treatment is by surgical excision, and it is important that extensions of the tumour should be followed and removed completely. Even so, recurrence is common, but this is always local and distant spread or malignant change never occur.

Schwannoma

This is a benign nerve tumour. It usually presents as a firm small round swelling in the path of a nerve. It is mobile, but mainly transversely to the line of the nerve. Diagnosis is confirmed on MRI scan, and treatment is surgical excision. Careful dissection under the microscope should allow removal with most of the nerve fibres left intact, but one small part of the nerve usually enters the tumour and has to be cut, mostly without significant noticeable effect. Malignant schwannoma is rare, and usually appears in the brachial plexus, in the root of the neck.

Enchondroma

A tumour of cartilage within a bone. The growth may cause noticeable swelling of the bone, but usually presents with pain, and x-ray reveals the diagnosis. The enchondroma may weaken the bone, in which case the diagnosis may be made when a fracture occurs, and again, x-ray provides the answer. The enchondroma can be removed from the bone. Opinions differ as to whether the cavity left should be filled with bone graft. If the remaining bone appears weak due to thinning, this may lead to earlier recovery of strength, but otherwise it is not essential and complete removal of the growth can lead to complete reformation of the bone. A low grade malignant form (chondrosarcoma) occasionally grows and is recognised by examination of removed tissue in a pathology lab.

Glomus tumour

The glomus is a microscopic structure which links the blood vessels of the skin (especially in the finger tip) to the autonomic nervous system. Its function is like a thermostat on a radiator – opening and closing the skin circulation in response to temperature and other factors. The cells of the glomus can form a tumour, which predictably is temperature sensitive. Glomus tumours are usually too small to be noticeable as a growth, but in their common position beneath the finger nail, they may be visible as a blue stain. A frequent feature of the glomus tumour is the fact that patients often have symptoms for many years before the diagnosis is made. The symptoms to watch for are very localized pain, point tenderness, cold intolerance and possibly a small area of blue discolouration beneath the finger nail, coinciding with the point of tenderness.

The symptoms can be cured by removal of the tumour. Once it has been identified this is not difficult. However small glomus tumours in the pulp of the finger or elsewhere in the hand may be difficult to find. Those under the fingernail can be removed by lifting up the whole nailbed and removing the lesion, then laying it down again. Recurrence is unusual, but does occur, and some patients develop multiple lesions.

Osteoid osteoma

A bone tumour that presents with pain. The growth is usually very small, and difficult to see on x-ray. Persistent unexplained and very localized pain is the feature that may trigger thought of a diagnosis of this tumour. A recognized characteristic of osteoid osteoma is that the pain responds well to aspirin. A bone scan shows up an area of increased uptake, and x-ray and CT scan should show the lesion clearly. As it is a small growth tucked inside the bone, removal is challenging and requires accurate localization. Occasionally an osteoid osteoma grows on the surface of a bone, in which case the presentation is of soft tissue swelling rather than bone pain.