Download - How To Approach a “bump”
Michelle Ghert, MD, FRCSC
300/100,000 benign soft-tissue, but only 2/100,000 malignant soft-
tissue Soft tissue sarcoma can occur at any
age Rabdomyosarcoma most common in children
Synovial & epitheliod sarcomas common in young adults
20-40% of STS occur in extremities 1/3 in upper extremities & 2/3 lower
extremities 30% occur in trunk and pelvis. 10% occur in head & neck 1/3 of STS present as small superficial
masses
Fibrous Tissue Adipose Tissue Striated Tissue Smooth Tissue Synovial Tissue Blood Vessels Lymph Vessels Peripheral Nerve Myofibroblast
Fibroma/Fibrosarcoma Lipoma/Liposarcoma Rhabdomyoma/Sarco Leiomyoma/Sarcoma Mesothelioma Angioma/Sarcoma Lymphangioma/sarco Neuroma/
Schwannoma Malignant Fibrous
Histiocytoma
Superficial tender mass, red in color,rapidly enlarging, swollen, warm, fluctuant on examination?
1)Synovial cyst2)Hematoma3)Abscess
Hx of direct trauma, therapeutic anticoagulation, clotting deficiency, subcutaneous ecchymosis, compressible on examination?
1)Abscess2)Hematoma3)Synovial Cyst
Para-articular mass, trans-illuminate, fluctuation in size independent of activities, tense but indentable with digit pressure on examination?
1) Bakers cyst2) Hematoma3) Shwannoma4) Synovial Cyst
Malignant:Pleiomorphic SarcomaFibrosarcoma(FS)LiposarcomaSynovial SarcomaEpitheliod SarcomaClear Cell SarcomaRhabdomyosarcoma
Benign:1-Lipoma2-Desmoid3-Schwannoma4-Hemangioma
Size: < 5cm
Depth: Superficial
Grade: Low
>= 5cm
Deep
High
LOW GRADE: HIGH GRADE:
Good Differentiation Hypocellular More Stroma Hypovascular Minimal Necrosis
Poor Differentiation Hypercellular Minimal Stroma Hypervascular Much Necrosis
Very little information is gained. Some infections may result in elevated: WBC, ESR & CRP But this finding nonspecific. Elevated lactate dehydrogenase seen
in lymphoma. Suspicion of Gout----- Serum Uric Acid
Confirm the diagnosis of a cyst Does mass have a cystic component? F/U a small mass that is being followed
without excision Accurately asses an increase in growth
of the mass by examining the change on the ultrasound studies
Identifying and characterizing mineralization within the soft tissue masses(myositis ossification)
Generally reserved for staging
Most sensitive and specific radiograph study for imaging soft tissue masses
Helpful for preoperative planning prior to excision the mass
Excellent differentiation of various tissue types
Indication:
1- Clinical & radiographic evaluation does not yield a conclusive diagnosis
2-When the mass must be removed
2 CRITERIA SHOULD BE MET BEFORE 2 CRITERIA SHOULD BE MET BEFORE PROCEEDING:PROCEEDING:
1) The pathologist should have experience in musculoskeletal pathology
2)The surgeon should have experience in dealing with all of the possible diagnoses considered in the pre-biopsy differential diagnosis
Fine-needle aspiration
Core-needle
Open biopsy
Typically performed by an interventional or MSK radiologist
Minimal morbidity for the patient Core is better than FNA Core is 85% diagnostic If non-diagnostic tissue is
obtained, the mass should not be assumed to be benign
Incision in line with resection incision Longitudinal in extremities Intramuscular if possible (to bury
hematoma) Avoid NV structures and joints No skin or muscle flaps Meticulous hemostasis Tight closure Approach soft tissue mass or weakened
area of bone Drain if necessary, in line and distal to
incision Send tissue for frozen: ‘lesional tissue’
Treatment of soft tissue masses is based on their size and location
4 categories: small superficial large superficial small deep large deep
The piecemeal removal of the tumor. Benign proliferative lesions (PVNS,
gout)
Complete removal of the tumor with pseudocapsule left intact
Benign tumors
Removal of the tumor with a cuff of normal tissue without exposing the pseudocapsule
Malignant soft-tissue lesions
Involves removal of the entire muscle compartment or compartments involved by the tumor
Rare
Less than 5cm Easily palpable beneath the skin & not
firm with muscle contracture Slow or stable growth pattern Long history
If excisional biopsy is chosen, then marginal excision can be done
Deep fascia should be left undisrupted
More than 5 cm. Easily felt beneath the skin, and not
firm with muscle contracture.
Almost always need evaluation with MRI
If a diagnosis is unclear by MRI, then biopsy
Less than 5 cm located in deep fascia Becomes more firm with muscle
contracture Small deep mass should be always
investigated by MRI
If MRI suggests a lipoma or peripheral nerve sheath mass (shwannoma), marginal excision
Non-specific MRI may represent a soft tissue sarcoma
More than 5cm located deep to the fascia.
MRI (high risk) Refer to musculoskeletal oncologist
Wide surgical excision Radiation, pre or post operative Chemotherapy, while controversial, can
be considered for patient with high grade, large, deep soft tissue sarcoma
Longstanding, small, static subcutaneous ‘bumps’ can be treated with ultrasound, observation and marginal excision if desired
Rapid growth, deeper lesions and those 4-5 cm should be imaged with MRI
High-risk lesions should not be excised, but biopsied
Always use longitudinal incision in extremities