Spindle Cell Sarcoma of the Bone

This information has been written for patients, their families and friends and the general public to help them understand more about a rare form of cancer known as spindle cell sarcoma. This section will detail what spindle cell sarcoma is and how this tumour type can be diagnosed and treated.

For a downloadable source of this information, please view our 'Downloadable Information Materials' page to view all of our fact sheets.

Spindle cell sarcoma is a soft-tissue tumour which can start in the bone. Spindle cell sarcomas of the bone are often found in the arms, legs and pelvis. They most commonly arise in patients over the age of 40 and are extremely rare - making up just 2-5% of all primary bone cancer cases.

There are four subtypes of spindle cell sarcoma of the bone, although the majority follow the same diagnosis and treatment methods as a much more common form of primary bone cancer, known as osteosarcoma.

Sarcoma is the name given to a cancer that starts in the connective tissue. The connective tissue plays a supportive role in the body and includes tissues such as the bone, cartilage, muscle and fat.

Spindle cell sarcoma is a form of sarcoma that is referred to this way due to the appearance of its tumour cells when they are looked at under a microscope. The cells which make up a spindle cell sarcoma are long and narrow, which is known as a ‘spindle-cell shape’(1).

There are three different types of spindle cell sarcoma of the bone, these are:

Pleomorphic Undifferentiated Sarcoma (previously known as Malignant Fibrous Histiocytoma)
Fibrosarcoma
Leiomyosarcoma

Spindle cell sarcoma can arise in any bone, in any area of the body. Though the majority of these tumours are found in the long bones of the body, such as the thigh bone (known as the femur), the area around the knee, the shin bone (known as the tibia) or the upper arm (known as the humerus)(1,2). Additionally, one type of spindle cell sarcoma, known as undifferentiated sarcoma of the bone, is quite commonly found in the pelvis and fibrosarcomas can develop in the head and neck area.

Spindle cell sarcomas of the bone tend to follow a similar course to that of a more common form of primary bone cancer, known as osteosarcoma. Osteosarcoma has paved the way in developing new methods for diagnosis and treatment plans for patients. Therefore, due to their similarities, spindle cell sarcoma patients undergo the same treatment methods as an osteosarcoma patient would(1,3).

The different types of spindle cell sarcoma of the bone can overlap with one another in their appearance, and there is still some variation in the terminology used amongst health care professionals surrounding the diagnosis of this tumour. For this reason, the exact number of spindle cell sarcoma of the bone cases is still largely unknown, though it is reported that they make up just 2-5% of all primary bone cancer cases. There is a slightly higher number of cases seen in male patients than in female patients(1).

This type of cancer can affect anyone, at any age. Though spindle cell sarcoma is most commonly diagnosed in adulthood, affecting patients over the age of 40 years old(3).

There are three different types of spindle cell sarcoma of the bone and these are able to start in any bone in the body. For this reason, the symptoms experienced by patients can vary between patients and it is difficult to predict the exact symptoms an individual may face.

Often, the symptoms are common and difficult to pinpoint to one disease. Hence, early diagnosis is not always possible and in some cases the tumour may be relatively advanced before the symptoms are reported or confirmed as a spindle cell sarcoma of the bone.

The most commonly reported symptoms of spindle cell sarcoma patients are:

Bone pain – this may be continuous or may come and go
A pathological fracture may occur– this is a fracture that has occurred due to the weakening of a bone from a disease
Swelling
The presence of a lump or mass
Tenderness in the area
Reduced mobility of the area, or of a joint in a nearby location to the affected area
Fatigue – which is extreme tiredness caused by a disease
Malaise – which is the general feeling of unwell and discomfort

Spindle cell sarcomas of the bone are commonly known to present with a pathological fracture(1). A pathological fracture is a fracture of the bone occurring due to the bone being weakened in that area as a result of a disease, such as cancer. A pathological fracture of the bone can encourage the circulation of tumour cells which leads to the local spread of a spindle cell sarcoma. Therefore, it is important that if a pathological fracture presents it is investigated further.

For more information on the symptoms of primary bone cancer please refer to our About Primary Bone Cancer information section

There are three types of spindle cell sarcoma of the bone(1,3). These three types can be classified by radiologists (who look at images of the tumour following diagnostic scans) or by pathologists (who look at the type of cells in the tumour under a microscope following a biopsy of the bone).

The three types of spindle cell sarcoma are:

Pleomorphic Undifferentiated Sarcoma (also known as Malignant Fibrous Histiocytoma)
Fibrosarcoma
Leiomyosarcoma

Pleomorphic Undifferentiated Sarcoma (also known as Malignant Fibrous Histiocytoma)

Pleomorphic undifferentiated sarcomas were previously known as malignant fibrous histiocytomas (referred to as MFH)(4). The change in the naming of this tumour type is due to an increased knowledge of spindle cell sarcoma, which has allowed other tumours of the connective tissue (such as leiomyosarcoma and rhabdomyosarcoma), to be accurately diagnosed as separate tumours to MFH. Therefore, the tumours that would still be classified as an MFH are now known as their own tumour type, called a pleomorphic undifferentiated sarcomas.

Unlike the other types of spindle cell sarcomas, pleomorphic undifferentiated sarcoma of the bone are not made up of any particular specialised cell. Instead, the cancerous cells of the bone are relatively undeveloped and it is difficult to determine which normal cell type they have developed from.

Undifferentiated pleomorphic sarcomas tend to occur in older patients, aged around 60 to 70 years of age(4).

Fibrosarcoma

Fibrosarcomas are very rare and are mostly found in middle-aged adults This type of sarcoma is referred to as a fibrosarcoma as it is predominately made up of specialised cells known as fibroblasts. Fibroblasts create the structural framework of many tissues(5).

The most common location for a fibrosarcoma to occur is the thigh bone (which is known as the femur).

Leiomyosarcoma

Leiomyosarcoma of the bone is extremely rare and therefore there is little known about this spindle cell sarcoma subtype. It is characterised by the presence of cells known as ‘differentiated smooth muscle cells’, but tends to be managed in a similar manner to osteosarcoma - a more common form of primary bone cancer(6).

Although leiomyosarcoma can affect a wide range of patients, it is known to affect middle-aged patients most often(2,6).

Spindle cells make up part of the body’s natural healing process in response to injury. Normally, once the area being repaired has healed, spindle cells will stop dividing to prevent the build-up of these cells. However, spindle cell sarcoma forms when these spindle cells begin to divide uncontrollably, creating a mass of cells that forms a tumour.

Some individuals may have a genetic predisposition to spindle cell sarcoma. This means gene irregularities are passed down from their family members, making them more likely to develop this cancer. In addition to this, there are numerous conditions, or diseases, of the bone that are linked to the development of a spindle cell sarcoma.

Some causes and risk factors that increase the likelihood of an individual developing a spindle cell sarcoma include:

Paget’s Disease of the Bone

Paget’s disease of the bone is a condition that causes the bones to become weakened and misshapen. This can increase the risk of a patients developing diseases of the bone, such as spindle cell sarcoma(1,2,7). For more information of Paget’s disease please visit The Paget’s Association at www.paget.org.uk.

Undergoing previous radiotherapy

For previous radiotherapy to be classified as a risk factor of spindle cell sarcoma, the affected bone must have been included in the field of radiation. There is usually a long period, usually 9 years or more, that pass before the sarcoma will develop following radiotherapy(1)

Fibrous Dysplasia

Fibrous dysplasia is a common disorder of the bone which replaces normal bone tissue with undeveloped connective tissue. On very rare occasions, this has been known to lead to the development of fibrosarcoma (a subtype of spindle cell sarcoma)(5,7)

Bone Infarction

Bone infarction is the death of bone tissue in areas due to a poor blood supply and therefore a lack of oxygen to bone(5)

Osteomyelitis

Osteomyelitis is the inflammation of the bone or the bone marrow(5,7)

Patients with different types of primary bone cancer are assessed in similar ways. For this reason, diagnostic tests are covered in more detail in our About Primary Bone Cancer information section.

This section aims to provide information on the specific details of diagnosing a spindle cell sarcoma and to discuss other conditions that may appear diagnostically similar to a spindle cell sarcoma.

The first step in diagnosing any spindle cell sarcoma is usually a trip to the GP. Diagnosis of a suspected bone tumour usually follows a clinical examination and an X-ray. It is very common to be referred to a bone cancer specialist for a second opinion and confirmation of the diagnosis.

Further tests are likely to be carried out to confirm the presence of a spindle cell sarcoma, these tests include: CT scans, MRI scans, a biopsy of the bone and blood tests.

More information on X-Rays, CT Scans, MRI scans, bone biopsies and blood tests can be found here.

The symptoms of spindle cell sarcoma can be non-specific and may be different depending on the exact location of the tumour and the tumour type. It is important that an accurate diagnosis is made, confirming the type of spindle cell sarcoma that is presenting, to allow the most appropriate treatment plan to be put into place

Spindle cell sarcomas of the bone often present with a pathological fracture; this is a fracture of the bone that has occurred due to the bone being weakened in the presence of a disease. A pathological fracture of the bone may mean that there is an opportunity for the cancerous cells to escape from the tumour into the blood stream, causing the spread of the spindle cell sarcoma to other areas of the body. Therefore, it is important that if a pathological fracture occurs it is investigated further using an MRI (magnetic resonance imaging) scan to determine the reasoning behind this fracture(1).

X-Rays, CT (computerised tomography) scans and MRI scans cannot definitively diagnose a spindle cell sarcoma of the bone. However, these scans can provide important information on the location of the tumour, the size of the tumour and determine if the tumour has spread elsewhere in the body. These scans also look if there is any damage to the bone, which can let doctors know how advanced the tumour is.

Taking a biopsy of the bone is needed to confirm the diagnosis of a spindle cell sarcoma of the bone. This specialist procedure uses a needle to take a small sample of the tumour so it can be looked at by a specialist doctor (known as a pathologist) under a microscope(1,5). This includes looking at the sample and doing special tests for certain bone matrix proteins and molecules that are specific to this tumour type. In order to take a sample from an area that will represent the whole tumour, a CT scan is often carried out alongside the biopsy to guide the doctor.

Results from a biopsy can take up two weeks to analyse and they enable doctors to confirm the presence and specific type of spindle cell sarcoma of the bone - which is extremely valuable when determining the best treatment plan for each individual patient.

To learn more about biopsies please see our About Primary Bone Cancer information section.

AN ALTERNATIVE DIAGNOSIS?

When diagnosing spindle cell sarcoma of the bone it is important to rule out the presence of various other diseases, or conditions, which may appear in a similar manner to a spindle cell sarcoma in terms of signs and symptoms. It is important the correct diagnosis is made to ensure the treatment provided is suitable. It can sometimes take a long time to confirm a diagnosis of primary bone cancer after a biopsy, this is because these tumours are rare and sometimes difficult to identify. Diseases with similar symptoms or signs are known as ‘differential diagnoses’.

If the diagnostic tests show that the patient does not have a spindle cell sarcoma of the bone, there are a number of other conditions that may be presenting, including:

Osteolytic Osteosarcoma

Spindle cell sarcomas are known to behave in a similar manner to osteosarcoma, a common form of primary bone cancer, and are therefore treated in a similar manner. Clinicians are able to tell the difference between these two cancers of the bone as spindle cell sarcomas do not produce a bony substance known as osteoid, which osteosarcomas do(1,2)

Metastatic Carcinoma

When a cancer spreads from one area of the body to form a tumour in another area of the body, the secondary tumour is known as a metastatic carcinoma. Many cancers spread to the bone, including those from the breast, lung and kidney, and so an angiosarcoma of the bone is often thought to be a metastatic carcinoma(1).

Aneurysmal Bone Cyst

An aneurysmal bone cyst is a non-cancerous, blood-filled cyst which can start in any bone in the body. These cysts grow in the bone and cause pain and possible fracturing - which are signs and symptoms seen in spindle cell sarcoma(5,8)

If a diagnosis of spindle cell sarcoma of the bone is confirmed, you will need treatment in a bone cancer centre.

For more information on the locations of Bone Cancer Centres please click here.

In general, the treatment of primary bone cancer is largely down to the location of the tumour and type of tumour that is presenting.

Spindle cell sarcomas of the bone are known to behave in a similar manner to a more common form of primary bone cancer, known as osteosarcoma. Therefore, the management of spindle cell sarcoma is based largely on the treatment methods used for osteosarcoma patients. Osteosarcomas have led the way for many developments in the treatment of primary bone cancers, and so following the same treatment path provides spindle cell sarcoma patients with the best possible outcome(1,5).

Surgery

The surgical removal of the tumour is carried out wherever possible. As with the majority of primary bone cancers, a margin of healthy tissue is removed alongside the tumour, which is known as taking a ‘wide-surgical margin’. This ensures all tumour cells are removed and lowers the risk of the tumour returning at a later date (a process which is known as tumour recurrence)(1).

The surgical procedure carried out to treat a spindle cell sarcoma is known as ‘limb-sparing surgery’, which aims to remove the tumour while preserving as much of the normal function and cosmetic appearance of the limb as possible.

Common limb-sparing surgical procedures performed are:

Resection - the affected area of bone is removed
An Autograft/Autologous graft - the affected area of bone is removed and reconstructed using the patients’ own bone tissue from another area of their body
An Allograft - donated tissue is used to reconstruct the affected area of the bone once the tumour has been removed
A Metallic Replacement - once the tumour is removed the area of damaged bone is replaced with a metal implant known as a prosthesis. This procedure usually requires rehabilitation therapy after surgery
Irradiation/Reimplantation - damaged bone is removed and treated with radiation, destroying the cancer cells, before being put back into the body

In the past, amputation of the limb was required in order to effectively treat and remove the entire tumour. However, this is now much less common and surgical procedures are planned alongside chemotherapy and radiotherapy to ensure as much functional and cosmetic normality of the limb is retained as possible, without the need for amputation(6).

Chemotherapy

As seen in the treatment of osteosarcomas, chemotherapy is frequently used alongside surgery when treating spindle cell sarcomas of the bone. Depending on how advanced the tumour is, chemotherapy may be given before or after surgery has taken place.

Chemotherapy that takes place before surgery is known as ‘neoadjuvant chemotherapy’. Neoadjuvant chemotherapy is used to shrink the tumour by destroying the tumour cells and controlling any spread of the tumour. This allows the surgeon to remove the tumour much easier and creates a more successful surgical procedure.

Chemotherapy can also be used after surgery, which is known as ‘adjuvant chemotherapy’. This additional round of chemotherapy ensures any remaining tumour cells are destroyed.

Every individual patient is treated differently, and has a treatment plan made specifically for them. The chemotherapy an individual receives depends on the type, location and size of their tumour. Therefore patients may not always receive both chemotherapy and surgery, or they may not receive chemotherapy both before and after their surgery.

When chemotherapy is used, the following drugs are most commonly given:

Methotrexate
Doxorubicin
Cisplatin
Ifosamide

These chemotherapy drugs may be used alone or in combination with one another(1).

Radiotherapy

On some occasions, radiotherapy may be used after surgery as an extra measure to ensure all the tumour cells in the area are destroyed.

Radiotherapy may be required if the patient has not responded well to surgery, or if the surgery was difficult and not all of the tumour could be removed. In these cases, radiotherapy is known to largely reduce the risk of the tumour returning at a later date(1,4,9).

Radiotherapy may also be used in patients with poor health who may not be fit to undergo surgery or require treatment that manages the symptoms of the cancer - which is known as ‘palliative radiotherapy’.

For more information regarding treatment procedures, including surgery, chemotherapy and radiotherapy, and their possible side-effects, please visit our About Primary Bone Cancer information page.

Outcome

The long-term outlook for patients with a spindle cell sarcoma of the bone, which is often referred to as a patients prognosis, is very dependent on the type of the tumour, the location of the tumour and if the tumour has spread elsewhere in the body. The risk of a spindle cell sarcoma spreading elsewhere in the body varies in each individual and each type of spindle cell sarcoma of the bone. If the spread of the tumour does occur, it most commonly does so to the lung - which is referred to as pulmonary metastasis.

It is important to bear in mind that patients receiving treatment outside of the UK may receive different tests and treatment in accordance to the treatment guidelines set out in that specific country. If you have any questions or concerns regarding this please discuss this with your medical team or contact The Bone Cancer Research Trust for more information.

If you would like more information about spindle cell sarcoma of the bone please contact us.

Key References:

1. Athanasou, N, Bielack, S, De Alava, E, Dei Tos, A.P, Ferrari, S, Gelderblom, H, Grimer, R, Sunday-Hall, K, Hassan, B, Hogendoorn, P.C.W, Jurgens, H, Paulussen, M, Rozeman, L, Taminiau, A,H,M, Whelan, J, Vanel, D. Bone Sarcomas: ESMO Clinical Practice Guidelines for Diagnosis, Treatment and Follow-Up. Annals of Oncology. 2010; 21(5): v204-v213. Available at: http://annonc.oxfordjournals.org/content/21/suppl_...

2. Kitay, A, Rybak, L, Desai, P, Villalobos, C,E, Wittig, J,C. Primary Leiomyosarcoma of the Proximal Tibia: Case Report and Review of the Literature. Bulletin of the NYU Hospital for Joint Diseases. 2008; 66(1):49-53. Available at: http://www.tumorsurgery.org/portals/0/pdf/publicat...

3. Grimer, R.J, Docker, C, Spooner, D. Primary Spindle Cell Sarcoma of Bone – An Assessment of Outcome. Orthopeadic Proceedings. 2003. Available at: http://www.bjjprocs.boneandjoint.org.uk/content/85...

4. Chen, K-H, Chou, T-M, Sheih, S-J. Management of Extremity Malignant Fibrous Histiocytoma: A 10-year Experience. Formosan Journal of Surgery. 2015; 48(1): 1-9. Available at: http://www.sciencedirect.com/science/article/pii/S...

5. Malawer, M.M, Helman, L.J, O’Sullivan, B. Devita, Hellmans, and Rosenberg’s Cancer: Principles and Pathology. Section Two: Sarcomas of the Bone. Volume Two: Eighth Edition. 2008. Lippincott, Williams and Wilkins. Philadelphia. Available at: http://sarcoma.org/publications/articles/devita.pd...

6. Brewer, P, Sumathi, V, Grimer, R, J,Carter, S,R, Tillman, R,M, Abudu, A, Jeys, L. Primary Leiomyosarcoma of Bone: Analysis of Prognosis. Sarcoma. 2012. Available at: http://www.hindawi.com/journals/sarcoma/2012/63684...

7. Horvai, A, Krishnan Unni, K. Premalignant Conditions of Bone. Journal of Orthopaedic Science. 2006; 11(4): 412-423. Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC278064...

8. Tomasik, P, Spindel, J, Miszczyk, L, Chrobok, A, Koczy, B, Widuchowski, J, Mrozek, T, Matysiakiewicz, J, Pilecki, B. Treatment and Differential Diagnosis of Aneurysmal Bone Cyst Based On Our Own Experience. Ortopedia Traumatologia Rehabilitacja. 2009; 11(5): 467-475. Available at: http://www.ncbi.nlm.nih.gov/pubmed/19920289

9. Hsu, H-C, Huang, E-Y, Wang, C, J. Treatment Results and Prognostic Factors in Patients with Malignant Fibrous Histiocytoma. Acta
Oncologica. 2004; 43(6): 530-535. Available at: http://www.tandfonline.com/doi/pdf/10.1080/0284186...

10. Dasari. S, Tchounwou, P,B. Cisplatin in Cancer Therapy: Molecular Mechanisms of Action. European Journal of Pharmacology. 2014; 5: 364-378. Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC414668...