Soft tissue sarcoma

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Non-cancerous soft tissue tumours

A non-cancerous, or benign, soft tissue tumour is a growth that does not spread (metastasize) to other parts of the body. Non-cancerous tumours are not usually life-threatening. They are typically removed by surgery and do not usually come back (recur).

There are many different types of non-cancerous tumours that develop in the different types of soft tissue. They are named and grouped based on the type of normal cells the tumour cells look like under a microscope.

Fat tissue

A number of non-cancerous soft tissue tumours start in the fatty (adipose) tissue of the body.

Lipomas are the most common type of non-cancerous soft tissue tumour. They often develop as a single, soft, painless lump that grows slowly. A small number of lipomas develop as many lumps or abnormal areas, called lesions. Most lipomas develop in the fatty tissue just under the skin, which is called subcutaneous tissue. They usually occur in the trunk of the body and the limbs.

Lipoblastomas develop in babies and young children. They are an unusual type of a lipoma made up of immature fat cells.

Hibernomas are non-cancerous tumours that grow slowly. They usually develop in the chest, or thorax. They can also develop in the trunk, limbs and the back of the abdominal cavity, which is called the retroperitoneum.

Fibrous tissue

Different non-cancerous tumours can develop in fibrous tissues.

Fibroma is a general term used to describe a group of non-cancerous tumours that start in the skin or fibrous soft tissues, such as tendon and ligaments. Fibromas are usually slow-growing tumours.

Elastofibromas are rare non-cancerous tumours that grow slowly. They usually develop between the lower part of the shoulder blade and the chest wall. Elastofibromas tend to occur in older adults and are thought to be caused by repetitive manual tasks. These tumours can grow to 5–10 cm (2–4 in) in diameter.

Superficial fibromatosis are small non-cancerous tumours that grow slowly. They usually develop in a hand, which is called palmar fibromatosis. They can also occur in a foot, which is called plantar fibromatosis, or the penis, which is called penile fibromatosis. They are more likely to develop in the feet or penis if they have already occurred in the hands. These tumours are likely to come back (recur) after they are removed.

Benign desmoid (deep) fibromatosis is a very rare non-cancerous tumour that grows slowly. It starts in the soft tissues deep in the abdomen. This type of tumour may grow into, or invade, nearby tissues. But it doesn’t spread to other parts of the body. There is also a cancerous form of  this type of tumour, which is called malignant desmoid (deep) fibromatosis.

Fibrous histiocytoma often occurs as one slow-growing lump. It is called a dermatofibroma or sclerosing hemangioma when it occurs in the skin.

Muscle tissue

Non-cancerous muscle tumours occur most often in smooth (involuntary) muscle. They may also develop in skeletal (voluntary) muscle.

Leiomyomas are non-cancerous tumours that develop in smooth muscle. They often occur as many painful lumps. Leiomyomas can start almost anywhere in the body, but are most common in the gastrointestinal (GI) tract and uterus. (A leiomyoma that develops in the uterus is also called a fibroid.) These benign tumours may also develop deep in a limb and in the abdominal cavity, or the retroperitoneum (the back of the abdomen).

Rhabdomyoma is a rare non-cancerous tumour that starts in skeletal muscle.

Blood vessels

Non-cancerous tumours of the blood vessels may also be called benign vascular tumours.

Hemangiomas are fairly common non-cancerous tumours. They are often present at birth, and can affect the blood vessels in the skin or internal organs. Hemangiomas sometimes go away without any treatment.

Benign glomus tumours usually develop around blood vessels under the skin of the fingers or in the hands, wrists and feet. They are also called perivascular tumours. They appear as a small bluish-red lump under the skin and can be quite painful. There is also a cancerous form of this type of tumour, which is called malignant glomus tumour.

Benign hemangiopericytoma is a rare non-cancerous tumour. It usually develops around smaller blood vessels in the legs, pelvis and the back of the abdominal cavity (retroperitoneum). These tumours are likely to come back (recur) after they are removed. There is also a cancerous form of this type of tumour, which is called malignant hemangiopericytoma.

Lymph vessels

The most common non-cancerous tumour that develops in the lymph vessels is called lymphangioma. These tumours can occur at any age, but they are often present at birth or develop in children under the age of 2 years. They usually develop in the head and neck area. Lymphangioma are slow growing and look like a soft, doughy mass. They can grow quite large.

Non-cancerous tumours of the lymph vessels are sometimes grouped together with blood vessel tumours.

Nerve tissue

There are nerves  throughout the body. Tumours can develop anywhere along these nerves.

Neurofibromas are small, slow-growing lumps in the nerves in the skin, just under the skin (subcutaneous tissue) or in other parts of the body. Neurofibromas can become cancerous, especially if they occur in very large nerves, such as those in the upper arms or neck. They usually develop in adults in their 30s. People with neurofibromatosis type 1 (von Recklinghausen disease) may develop many neurofibromas.

Benign schwannomas are slow-growing tumours that start in Schwann cells. These cells make up the sheath, or protective covering, around the nerves. These tumours often develop in the head and neck, in the limbs and around the spine along the back of the abdomen (retroperitoneum). They are usually less than 5 cm (2 in) when first diagnosed. But they can grow quite large, especially if they develop in the retroperitoneum. They occur most often in adults 20–50 years of age. Schwannomas are also called neurilemmomas. There is also a cancerous form of  this type of tumour, which is called malignant schwannoma.

Neuromas are tumours that start in nerve cells. Acoustic neuroma starts in the cells of the nerve that connects the brain and ear, which is called the auditory nerve. Morton’s neuroma occurs in nerves near the toes.

Benign tumours of uncertain tissue type

Tumours are usually named and grouped based on the type of normal cells the tumour cells look like under a microscope. Some non-cancerous tumours have not been linked to a type of soft tissue cell. Doctors don’t know what type of cell these tumours started from.

Myxoma is a rare non-cancerous tumour that is usually found in the large muscles of a limb. But it does not really develop from muscle cells. These tumours make large amounts of mucus-like material, which distinguishes them from other tumours.

Granular cell tumours usually develop in the mouth, but they can also occur almost anywhere in the body. Experts think these tumours start in nerve cells, but they don’t know for sure.

PEComas are a rare group of tumours that can develop anywhere in the body. They are also called perivascular epithelioid cell tumours. Experts think these tumours start in the cells surrounding blood vessels, but they don’t know for sure. PEComas can be either non-cancerous or cancerous. Non-cancerous PEComas include angiomyolipoma, which develops in the kidneys, and lymphangioleiomyomatosis, which develops in the lungs.

 

Nodular tenosynovitis is a slow-growing lump that occurs in the hands, feet, ankles or knees. Nodular tenosynovitis develops most often in adults 20–50 years of age.

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