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7/27/2019 Approach to Bone Tumor Diagnosis
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Diagnostic Approach to Musculoskeletal Tumors
Nur Fatini bt Chok
11 2011 142
Department of Surgry
RSUD Ciawi
JulyAugust 2013
Acknowledgments
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Alhamdulillah, thanks to God because allowed me to submit this manuscript within
the time given. Although there were a lot of things to settle down within this seven weeks, He
had help me to sFpent some time to finish this manuscript.
Second, I would like to thank to my consulant, dr. Dhevariza, the Orthopedist who
sincere and faithfully guide and help me to write this manuscript.
Not forgotten, thank you to my team-mate, who had help me in order to finish up this
manuscript. Thank you for all your ideas and discussion that we had about this topic.
Sincerely, The consulant,
(Nur Fatini Binti Chok) (dr. , Dhevariza, the Orthopedist )
Introduction
Musculoskeletal tumors are a rare and diverse group. Sarcomas of the bone and cartilage
comprise only 0.5% of all malignancies in humans. Their incidence is considerably higher
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in children than adults. The incidence of soft tissue sarcomas is 3 to 4 times higher, and the
majority of these cases are seen after the fifth decade. Benign bone and soft tissue tumors are
100 times more common than malignant tumors, with an overall incidence of300 per
100,000 population. The incidence per year of breast, prostate, and lung cancers in the
United States of America is nearly 180,000 to 200,000 each, reflecting the low incidence of
primary bone and soft tissue tumors. As the survival of patients with carcinomas is gradually
extending, presentation with bone metastases will also rise.
A general orthopedic surgeon or radiologist in the community may encounter only few cases
of bone tumors per year. Patients with an unknown musculoskeletal tumor should be referred
to a specialist center, because the cases are managed in close interaction between the
orthopedic oncologist, radiologist, and the pathologist, and the outcomes are superior.2
This
approach will often eliminate unnecessary diagnostic studies and inappropriate and
inadequate biopsies, which may delay the diagnosis and adversely affect the outcome.
Approach to Bone Tumor Diagnosis
General Considerations:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3036513/#r27185-2http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3036513/#r27185-2http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3036513/#r27185-2http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3036513/#r27185-27/27/2019 Approach to Bone Tumor Diagnosis
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Bone Tumors can be divided into primary and secondary. Secondary tumors can be further
subdivided into
Metastatic tumors
Tumors resulting from contiguous spread of adjacent soft tissue neoplasms Tumors representing malignant transformation of the pre-existing benign lesions.
Metastatic cancers are the most frequent malignant tumors found in bone. They are by far
more common than primary bone tumors and are characterized by the following:
Predominant occurrence in two age groups: adults over 40 years of age and childrenin the first decade of life.
Multifocality and predilection for the hematopoietic marrow sites in the axial skeleton(vertebrae, pelvis, ribs and cranium) and proximal long bones. Metastases to long
bones distal to the elbows and knees are unusual. Metastases to the small bones of the
hands and feet are even rarer. Occasionally, metastases may appear as solitary lesions
(particularly true for the lung, kidney and thyroid cancer).
Most common malignancies producing skeletal metastases:
Adults More than 75% of skeletal metastases originate
from carcinomas of the prostate, breast, kidney,
and lung. Also common are metastases from
thyroid and colon cancers. And do not forget
melanoma.
Children Neuroblastoma, rhabdomyosarcoma, and
Retinoblastoma
Radiographic appearance of the metastatic tumors can be :
Purely lytic (kidney, lung, colon, and melanoma) Purely blastic (prostate and breast carcinoma) Mixed lytic and blastic (most common appearance)
Primary bone tumors are characterized by the following:
1. Predominant occurrence in the first 3 decades of life, during the ages of the greatestskeletal growth activity. The commonest sites for many primary tumors, both benign and
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malignant, are in the distal femur and proximal tibia, the bones with the highest growth
rate.
2. Relatively specific radiographic presentations. In some cases, the diagnosis can beconfidently made based on the radiographic features alone.
3. Benign tumors are by far more common than malignant ones. Some of them are not trueneoplasms, but rather represent hamartomas (eg., osteochondroma). The most common
benign tumors are osteochondroma, non-ossifying fibroma, and enchondroma.
4. Some primary bone tumors are difficult to classify as benign or malignant. For example,giant cell tumor of bone is very aggressive locally but only rarely metastasizes.
5. Among primary malignant neoplasms, osteosarcoma and multiple myeloma have thehighest incidence, followed by chondrosarcoma and Ewing's sarcoma.
Two important features of bone tumors:
1. The ability of some to dedifferentiate (eg., enchondroma or a low-grade chondrosarcomatransforming into a high-grade sarcoma)
2. Tendency of high-grade sarcomas to arise in damaged bone, at the sites of bone infarcts,radiation osteitis and Paget's disease.
Relevant clinical information
1. Age (probably the most important clinical clue).
Age group Most common benign
Lesions
Most common
malignant tumors
010 simple bone cyst
eosinophilic granuloma
Ewing's sarcoma
leukemic involvement
metastatic
neuroblastoma
1020 non-ossifying fibroma
fibrous dysplasia
simple bone cyst
aneurysmal bone cyst
osteochondroma (exostosis)
osteoid osteoma
osteosarcoma,
Ewing's sarcoma,
Adamantinoma
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osteoblastoma
chondroblastoma
chondromyxoid fibroma
2040 Enchondroma
giant cell tumor
chondrosarcoma
40 and above Osteoma metastatic tumors
myeloma
leukemic involvement
chondrosarcoma
osteosarcoma (Paget's
associated)
MFH
Chordoma
Summary:
Primary osteosarcoma and Ewing's sarcoma are tumors of children and young
adults. Occurrence of chondrosarcomas in children or Ewing's sarcoma in middle-aged
patients is extremely unusual. In individuals older than 40 years, the commonest form of
skeletal malignancy is metastatic cancer. Of the primary bone tumors in this age group,
multiple myeloma and chondrosarcoma are most commonly encountered. Osteosarcomas in
this age group are often secondary malignancies, which develop at the the sites of bone
damage. Giant cell tumor, a locally aggressive lesion, almost exclusively occurs in skeletally
mature patients, 20 to 50 years of age, with closed epiphyses. It is practically never seen in
children or patients older than 60 years.
2. Pain (although a non-specific symptom, it may help in differential diagnosis)Generally, benign non-growing lesions tend to be asymptomatic and represent incidental
findings. Pain may be a symptom of:
Growing lesions. This category includes locally aggressive lesions (eg., aggressiveosteoblastoma and GCT), and malignant tumors
Pathologic fracture complicating either benign or malignant tumor Significant local tissue reaction to the tumor.
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The following clinical symptoms are worth remembering since they may help in the
differential diagnosis:
Osteoid osteoma - small lesion, but highly irritative to adjacent tissues andtypically causes intense night pain relieved by non-steroidal antiinflammatory
drugs. Osteoid osteomas may also occur close to the articular surface of a joint,
causing severe inflammatory synovitis, which often obscures the presence of the
tumor.
Enchondroma vs. chondrosarcoma, grade 1 - histologically, the distinctionbetween a grade 1 chondrosarcoma and an enchondroma is extremely difficult, as
histologic features overlap considerably. The distinction is based on the behavior
of the lesion. One of the clues to clinical behavior is the presence of pain. Low-
grade chondrosarcoma is a growing tumor and, therefore, presents with pain.
Enchondromas tend to be asymptomatic, unless associated with a pathologic
fracture.
3. Multiple lesionsAlthough both benign and malignant tumors may be multifocal, benign lesions tend to
show symmetrical distribution.
Radiological correlation
The following imaging studies are commonly used in evaluation of bone tumors:
1.Plain radiographusually the first imaging technique for a suspected bone lesion since it is inexpensive and
easily obtainable. It is also the best for assessment of general radiological features of the
tumor.
2. Computer tomographyis a method of choice when plain film assessment is difficult owing to the nature of the
lesion (eg., permeative pattern of destruction) or anatomic site (eg., sacrum). In addition,
CT is the best technique in assessment of matrix mineralization, cortical detail, and
detection of the cystic and fatty lesions.
3. MRI( method of choice for local staging. )It is superior to CT in the definition of medullary and extracortical spread and of the
relationship of the tumor to critical neurovascular structures. However, remember that the
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MRI appearances of the majority of bone tumors are totally non-specific. You need to
examine plain films or CT films to define a neoplasm.
4.Bone scintigraphis a highly sensitive but relatively non-specific technique. Its main role is in detection of
suspected metastases in the whole skeleton. It may also be helpful in the detection of
osteoid osteomas ("double density sign" is present in about 50% of cases and is highly
suggestive of this tumor).
Tabel 1 : Morphology of a bone lesion is combined with the age of the patient.
Radiographic examination should answer the following questions:
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What is the precise location of the lesion (type of bone and, if the long bone isaffected, where exactly the lesion is centered - cortex or medulla; epiphysis,
metaphysis or diaphysis)? Some tumors almost exclusively occur at specific sites;
many oth ers favor certain locations.
Is there any evidence of underlying bone abnormality (eg., bone infarct, Paget'sdisease)? High-grade sarcomas tend to arise in damaged bone.
Is the lesion multifocal? Does the tumor have a well-defined margin? Is there a rim of sclerotic bone? The
presence of a well-defined margin and a sclerotic rim strongly suggests a benign non-
growing lesion.
Is there evidence of significant cortical expansion or destruction? These findings areseen with locally aggressive or malignant tumors.
Is there an associated periosteal reaction and, if so, of what type? Does the lesion produce mineralized matrix (osteoid or cartilage)? Is there a soft tissue mass?
In many cases, the radiographic appearance of the lesion provides clues to its clinical
behavior. It allows estimation of tumor growth rate and discloses expansive or infiltrative
growth patterns characteristic of locally aggressive and malignant tumors.
Skeletal location
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While many lesions favor certain bones, some tumors almost exclusively occur at specific
sites :
Lesions Most common skeletal sites
Ewing's sarcoma
Multiple myeloma
Leukemia/lymphomaMetastatic cancers
Hematopoietic marrow sites in
the axial skeleton (vertebrae,
ribs, sternum, pelvis, cranium)and proximal long bones
(femur, humerus)
Non-ossifying fibroma Metadiaphyseal regions of the
tibia and distal femur (80%)
Does not occur in the flat bones, craniofacial
bones, the spine, or the small bones of the
hands/feet.
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Simple bone cyst The vast majority of SBCs is
found in the proximal humerus
(55%) and proximal femur (20%).
Chordoma Base of the skull or sacrum(90%)
Adamantioma Mid-shaft of tibia (90%), jaw bones
Chondroblastoma Long bones (knee area,
proximal humerus)-70%
Giant cell tumor Knee area, distal radius (65%)
Enchondroma Small bones of the hands and
feet (60%). This is in fact the
commonest tumor at these sites.
Chondrosarcoma (primary, and to
the less extent secondary)
Tends to develop in the axial
skeleton with 25% to 30%
occurring in the pelvic bones
Fibrous dysplasia Femur, tibia, skull and ribs
Ostochondroma Knee area, proximal humerus,
Pelvis
Osteoblastoma Spine (30%), mandible, long bones
Aneurysmal bone cyst Any bone; common in the
Spine
Chondromyxoid fibroma Knee area (30%), pelvis, small
bones of the feet
Hemangioma Spine, craniofacial bones
Site of Long Bone Involvement
(most primary bone tumors have favored sites within long bones; this may provide a clue to
diagnosis).
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Epiphyseal lesions:
1. Chondroblastoma (Ch) and Giant Cell Tumor (GCT) arealmost invariably centered in the epiphysis.
2. Chondroblastoma is a rare tumor seen in children andadolescents with open growth plates. GCT is the most
common tumor of epiphyses in skeletally mature
individuals with closed growth plates. GCT often shows
metaphyseal extension.
Metaphyseal intramedullary lesions:
1. Osteosarcoma is usually centered in the metaphysis.2. Chondrosarcoma and fibrosarcoma often present as
metaphyseal lesions. Osteoblastoma, enchondroma,
fibrous dysplasia, simple bone cyst, and aneurysmal bone
cyst are common in this location.
Metaphyseal lesions centered in the cortex:
Classic location for a non-ossifying fibroma (NOF).
Also, a common site for osteoid osteoma.
Metaphyseal exostosis:
Osteochondroma
Diaphyseal intramedullary lesions:
Favored location for Ewing's sarcoma, lymphoma,
myeloma. Common for fibrous dysplasia and
enchondroma.
Diaphyseal lesions centered in the cortex:
Adamantinoma, osteoid osteoma
Pattern of Growth and Bone Destruction
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Benign and non-growing (or extremely
slowly growing) lesions are well
circumscribed and show geographic pattern
of bone destruction with a sclerotic rim.
1. Geographic pattern refers to awelldefined area of lysis.
2. The sclerotic rim is more commonlyseen in the weight-bearing bones and
represents bone reaction to the lesion.
Its presence means that the bone has
been given sufficient time to react.
Some authors say that the sclerotic rim
signifies benignancy to about 95%.
If the lesion is growing more rapidly,it may
still show a well-demarcated zone of bone
destruction (geographic pattern), but it will
lack a sclerotic rim. With continued growth,
such lesions may show cortical expansion.
Expansile growth pattern is defined as visible
widening of the affected portion of bone. In
many cases, an interrupted periosteal rim will
surround the expanded portion of bone. This
pattern may be seen in locally aggressive
tumors and in lowgrade malignancies.
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Rapidly growing lesions are poorly defined
and may show aggressive, infiltrative
patterns of bone destruction (permeative or
"motheaten").
"Moth-eaten" pattern is defined as an ill-
defined zone of multiple small radiolucencies
that may coalesce.
Permeative pattern is characterized by
numerous tiny radiolucencies in between the
residual bone trabeculae. Due to the minute
size of radiolucencies the lesion may be
difficult to see and to delineate on the plain
film. Generally, the more rapidly growing a
lesion, the more difficult it is to see on plain
film. "Moth-eaten" and permeative patterns
are indicative of destruction involving both
medullary and
cortical bone. They are seen in highgrade
malignant neoplasms and in
osteomyelitis.
Types of Periosteal Reaction
The periosteum responds to traumatic stimuli or pressure from an underlying growing tumor
by depositing new bone. The radiographic appearances of this response reflect the degree of
aggressiveness of the tumor.
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Slow-growing tumors provoke focal cortical
thickening (solid periosteal
reaction, or "buttress")
Rapidly growing lesions penetrate
through the cortex causing separation
of the periosteum and formation of
lamellated new bone. If the
periosteum elevates to a significant
degree, it can break forming an acute
angle (Codman's triangle). This is
seen in malignant bone tumors and in
some other rapidly growing lesions
such as aneurysmal bone cyst, or in
reactive processes (osteomyelitis,
and subperiosteal hematoma).
Codman's triangle is usually free of
tumor unless infiltrated through its
open end or by transcortical growth.
Other types of periosteal reaction in
response to a rapidly growing lesioninclude "onion-skinning" and
spiculated "hair-on-end" types.
Note that bone metastases usually do not provoke a periosteal reaction.
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Pattern of matrix Mineralization
Mineralization patterns (calcification or ossification) are helpful in identification of bone
producing and cartilage producing tumors.
Osteoid. Malignant osteoid can be recognized
radiologically as cloudlike or ill-defined
amorphous densities with haphazard
mineralization. This pattern is seen in
osteosarcoma. Mature osteoid, or organized
bone, shows more orderly, trabecular pattern
of ossification.
This is characteristic of the benign bone-
forming lesions such as osteoblastoma.
Chondroid. Radiologically, it is usually
easier to recognize cartilage as opposed to
osteoid by the presence of focal stippled or
flocculent densities, or in lobulated areas as
rings or arcs of calcifications. They are best
demonstrated by CT. Whatever the pattern, it
only suggests the histologic nature of the
tissue (cartilage) but does not reliably
differentiate between benign and malignant
processes.
General Histologic Assessment of the Lesion
The following are the most important histologic features to consider:
Pattern of growth (eg., sheets of cells vs. lobular architecture) Cytologic characteristics of the cells Presence of necrosis and/or hemorrhage and/or cystic change Matrix production Relationship between the lesional tissue and the surrounding bone (eg., sharp border
vs. infiltrative growth)
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You should never try to make a diagnosis of bone tumor without integrating clinical,
radiological, and histologic appearances. Biologically different types of tumors may have
overlapping histologic features. Always obtain a list of differential diagnoses from a
radiologist, make a habit of reviewing the films, and develop a good working relationship
with an orthopedic surgeon. You are a part of a team.
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Soft Tissue Mass
Introduction
A soft tissue mass is one of the most common manifestations of a musculoskeletal tumor.
Proper diagnosis and treatment are essential to avoid the potential for loss of limb function
and to maximize the opportunity to cure a soft tissue sarcoma. The large majority of soft
tissue tumours are benign, with a very high cure rate after surgical excision. Malignant
mesenchymal neoplasms amount to less than 1% of the overall human burden of malignant
tumours but they are lifethreatening and may pose a significant diagnostic and therapeutic
challenge since there are more than 50 histological subtypes of STS, which are often
associated with unique clinical, prognostic andtherapeutic features. Over the past decade, our
understanding of these neoplasms has increased significantly, both from a histopathological
and genetic point of view. Careful physical examination and radiographic evaluation to
evaluate the size, depth and location of the mass, along with signs of neurovascular
involvement are essential for designing the best therapeutic approach.
History
When obtaining the patient history, consider:
1. The patient's age.Infants and children may present with benign lesions that can demonstrate local growth,
disfigurement, overgrowth of the extremity or loss of function (lipomas, hemangiomas,
lymphangiomas, neurofibromas, hamartomas, congenital or infantile fibromatosis). Soft
tissue sarcoma is extremely rare in children, but when it occurs, it is most likely to be
rhabdomyosarcoma. In adults, rhabdomyosarcoma is rare in the extremities.
2.The length of time that the lesion has been present.The patient may have had a benign soft tissue lesion for several years that has not grown
during that time. He or she may finally decide to "get this bump looked at," or may be
encouraged to consult a physician by a spouse or a friend. The pattern of growth is
important: A mass that has been present for years and that begins to grow may be
transforming from a benign to a malignant lesions, or it may simply be growth of a
benign soft tissue tumor. Rapid growth may also indicate that the mass may be malignant.
Growth of a soft tissue tumor, therefore, warrants further evaluation.
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3. The presence of pain.Although often tender to direct pressure, a soft tissue tumor itself rarely causes the patient
pain. The exceptions are peripheral nerve sheath tumors and rapidly growing soft tissue
sarcomas, which may cause pressure on surrounding structures and intra-compartmental
compression. If the patient is experiencing pain, also consider other diagnoses, such as
infection.
4. A history of trauma.Chronic repetitive trauma to the soft tissues may cause reactive fibrosis; a more acute,
severe injury may suggest myositis ossificans. It is not unusual for a patient to discover a
soft tissue mass after a major or minor trauma to the anatomical area -- or to mistakenly
believe that the injury caused the lesion. If the mass persists following trauma, a complete
workup is needed to establish whether it is related to the trauma (such as a persistent
hematoma) or is, in fact, a soft tissue tumor. Ask about a past history of penetrating
trauma or infection -- an old soft tissue infection or foreign body reaction may lead to the
late presentation of a calcified soft tissue mass.
5. Possible generalized conditions.Neurofibromatosis is the best example of a generalized disease that may be associated
with one or more soft tissue masses. A patient with this disease may present with benign
growth of a plexiform neurofibroma, or alternatively, a benign nerve sheath tumor may
transform into a neurofibrosarcoma. Multiple soft tissue benign myxomas may develop in
a patient with extensive fibrous dysplasia of the bones and cafe au lait spots (possibly
associated with premature onset of menses in the McCune-Albright syndrome). A patients
with Maffucci's syndrome (multiple bone enchondromas associated with soft tissue
hemangiomas) may present with transformation of a hemangioma to angiosarcoma.
6. Family history of soft tissue masses.This is particularly pertinent to the diagnosis of neurofibromatosis. In some cases of
familial cancer syndromes (Li-Fraumeni syndrome related to the inheritance of a mutant
p53 allele, for example), family members may have a high risk of developing soft tissue
sarcoma as well as other forms of cancer.
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Physical Examination
The physical examination of a patient with a possible soft tissue tumor includes the
following:
1. Depth.One of the most critical aspects of the physical examination is determining whether a
lesion arising deep to dermis is superficial or deep to fascia; most lesions developing
superficial to fascia are benign. In making this determination, attempt to move the lesion
over the fascia, both before and after the patient tenses the underlying muscle. If the
lesion moves with the muscle, it is likely deep to fascia. In some instances, it may be
impossible to tell if the lesion is deep or superficial; the lesion may even arise from the
fascia. As discussed below, the investigation and management of soft tissue lesions
depends on the depth of the mass. Those arising deep to fascia have the greatest risk of
malignancy. If the physical examination indicates that the lesion arises in fascia, deep to
fascia, or is uncertain, obtain imaging of the mass.
2. Size.After determining the depth, document the clinical size of the lesion in three dimensions.
Evaluate the condition of the overlying tissues, determining whether there is evidence of
inflammation that suggests either soft tissue infection or a rapidly growing tumor.
Tenderness could also indicate a rapidly growing tumor, a peripheral nerve sheath tumor,
or infection. Observe the surrounding skin for evidence of vascular changes that may
suggest multiple vascular malformations. Particularly in children, document evidence of
extremity overgrowth, including measurement of the extremity length and diameter.
3. Distal neurovascular status.Test for a nerve deficit or evidence of venous or arterial obstruction by evaluating distal
neurovascular status. Soft tissue tumors rarely cause a neurological deficit. Instead, nerve
deficit usually indicates that the tumor is arising in the peripheral nerve or is invading the
nerve. Examine the skin should for evidence of cafe au lait spots, dermatofibromas, or
axillary freckling, which may suggest neurofibromatosis or, in the case of cafe au lait
spots, fibrous dysplasia.
4. Regional nodes.Palpate the regional nodes, although soft tissue sarcomas rarely metastasize by
lymphangitic spread. Rhabdomyosarcoma and synovial sarcoma are the most likely
diagnoses if nodal metastases are found. Examine the other extremities and trunk for soft
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tissue masses; lipomas -- and less commonly liposarcoma -- may present in multiple sites.
Advanced metastatic carcinoma or lymphoma may spread to the non-nodal soft tissues;
therefore, evidence of a primary cancer elsewhere must be evaluated on both history and
physical examination.
5. Dermatological lesions.The only dermatological lesion related to musculoskeletal tumors is dermatofibrosarcoma
protuberans. This lesion is elevated above the dermis, purplish in color, and
characteristically develops satellite nodules as it grows. It behaves like a low-grade soft
tissue sarcoma and is generally managed in a similar manner. Subcutaneous malignant
fibrous histiocytomas may also result in invasion of the dermis, but generally malignant
mesenchymal lesions do not develop primarily in the skin.
Investigations
Results of the history and physical examination will guide the next steps:
1. Lesion Less than 5 cm in Diameter Observation is appropriate for this size lesion if it is also soft in consistency,
superficial to fascia, not enlarging, and not cosmetically or functionally troubling.
Measure and record the size of the lesion annually for 2 or 3 years.
If a lesion this size bothers the patient or is firm, painful, or enlarging, it cangenerally be removed by excisional biopsy, taking care to avoid violating the
underlying fascia. Send the specimen for appropriate pathological analysis, and if the
pathologist determines it to be a soft tissue sarcoma, locally curative management
can then be achieved by re-excising the surgical scar and incorporating the fascia as a
deep margin. Avoid excisional biopsy and obtain imaging and a needle or incisional
biopsy prior to excision if the lesion is located in an anatomical region that would
preclude later re-excision (for example, if a small lesion is located directly over the
bone in the subcutaneous tissues overlying the ulna or tibia).
2. Superficial Lesion Larger than 5 cm in Diameter Before attempting excision, evaluate a lesion this size by magnetic resonance
imaging (MRI). MRI is more appropriate for evaluating soft tissue tumors than
computerized tomography (CT) scan because the enhanced soft tissue contrast of
MRI allows for optimal demarcation of the lesion from surrounding normal soft
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tissues and for assessment of possible neurovascular involvement. It is likely that a
superficial lesion greater than 5 cm is lipoma. If this is confirmed by MRI, the
lesion may be observed or treated by excisional biopsy, depending on growth
characteristics and patient preference.
3. Needle or incisiona l, ra ther than ex ci sion al , biopsy should be undertaken if thelesion does not demonstrate a lipoma's typical well-demarcated, homogeneous pattern of
fat on MRI, or if there are any regions of high (bright) T2-weighted signal within the fat
of the tumor. Critically evaluate whether there is any evidence of edema surrounding the
superficial tumor. If the margin with normal surrounding subcutaneous fat is not sharp
and discrete on MRI, a biopsy should be done prior to excision.
4. Lesion Attached to Fascia, Deep to Fascia, or Depth UnknownMRIshould be undertaken to diagnose the lesion. The potential diagnoses for deep
lesions include benign conditions (intramuscular lipoma, hemangioma, myxoma, benign
peripheral nerve sheath tumor), benign aggressive tumors likely to recur locally after
simple excision (fibromatosis, hemangiopericytoma), and soft tissue sarcoma. Effective
treatment of many of these lesions will include wide surgical excision, and the likelihood
of achieving adequate surgical removal with minimal functional deficit is enhanced if the
patient is initially evaluated with MRI and carefully planned biopsy. Conversely, it may
be very difficult to perform adequate surgical excision with conservation of function if
the initial treating physician performed an excisional biopsy of a subfascial sarcoma,
which would cancer cells throughout the extremity. If the depth of the lesion is not
apparent on physical examination, the clinician should err on the side of ordering imaging
before attempting a biopsy.
Suspected or Confirmed Diagnosis of Soft Tissue Sarcoma
In these cases, metastatic staging with chest CTis necessary. Lymphatic spread to nodal
groups may be assessed clinically and, if suspected, assessed by CT scan.
If there is a history of trauma in a patient with a soft tissue mass, plain radiographs may
demonstrate the typical peripheral ossification pattern seen in myositis ossificans. In most
cases of soft tissue masses however, plain radiographs are of little value, although they may
demonstrate increased soft tissue lucency caused by a large fatty lesion or the calcification
occasionally observed in lipomas, liposarcomas, or synovial sarcomas. Bone scans are not
useful in most cases either, since soft tissue tumors rarely invade the bone cortex. If the bone
cortex is invaded, a CT scan may be more useful than either a bone scan or an MRI because a
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CT scan usually gives the best anatomical definition of the extent of bony destruction. In
general, though, MRI is the most effective imaging modality for soft tissue masses.
Blood work is not usually helpful in the diagnosis of soft tissue masses, although a complete
blood count, ESR and C-reactive protein may be helpful if infection is suspected. Patients
with myositis ossificans or soft tissue osteosarcoma may have an elevated serum alkaline
phosphatase.
Conclusion
In summarizing the investigation of patients with soft tissue masses, the following guidelines
are suggested:
If the lesion originates in or deep to fascia, or if the depth is uncertain, cross-sectionalimaging should be ordered.
1. If the lesion is superficial to fascia and larger than 5 cm, imaging should be undertaken. Inour experience, MRI is preferred to CT. However, if MRI is not available, CT is often
sufficient for initial investigation.
After localizing the lesion anatomically, it is necessary to obtain a biopsy of most deeplesions. An initial biopsy for superficial lesions that are greater than 5 cm is also suggested.
Deep soft tissue lesions should never be treated with an excisional biopsy. Doing so makes
definitive management much more difficult and therefore should be avoided.
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WHO classification of soft tissue tumours
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Reference:
1. Onder Ofluoglu, Stefano Boriani, Rakesh Donthineni ( 2010 ). Diagnosis and Planning inthe Management of Musculoskeletal Tumors: Surgical Perspective. Retrieved from
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3036513/
2. Violetta Barbashina, Joseph Benevenia, Meera Hameed ( 2004 ). Bone Tumors Tutorialfor Residents. Retrieved from http://www.umdnj.edu/tutorweb/
3. Woulde HJ, Robih Smithuis ( 2010 ). Bone Tumors Systemic Approach andDifferential Diagnosis. Retrieved from http://www.radiologyassistant.nl/ en/
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