Associated with higher rates of positive resection margins and local recurrence compared to other STS histologic subtypes
Rate of distant recurrence to lung is lower than for other STS types
Clinical History and Physical Examination
Most STS cases present as painless mass
History should include:
Duration of mass presence
Growth rate
Any associated local or systemic symptoms
Important to ask about potential risk factors for STS
Include history of radiation exposure or family history of malignancies
Physical examination should assess:
Mass characteristics: size, location, fixation to underlying structures, overlying skin changes
Potential evidence of neurovascular compromise
Imaging Evaluation
General examination should assess for lymphadenopathy or neurofibroma/café au lait spots
Association between neurofibromatosis type 1 and malignant peripheral nerve sheath tumors
Imaging workup should include:
Evaluation of primary site
Evaluation of sites of potential metastatic spread
Primary Site Imaging
For extremity, trunk, or head and neck STS:
Magnetic resonance imaging (MRI) scan generally preferred
T1-weighted MRI images provide excellent definition of anatomic relation between tumor and adjacent structures
T2-weighted images demonstrate tumor and any associated edema
Peritumoral edema can contain malignant cells
Important to identify for radiation and surgical planning
CT vs MRI Comparison
Demas et al. compared MRI and CT for STS lesions in extremities
Reported MRI scans showed tumor involvement in muscles in 23% of cases
Muscles appeared normal on CT scan
Panitch et al. found no significant difference between imaging modalities for preoperative evaluation
Most practitioners believe MRI is superior to CT for evaluation of soft tissue tumors
Biopsy Recommendations
Chest imaging to rule out pulmonary metastases for all cases except:
Low-grade tumors
Small (<5 cm) high-grade lesions
Can be helpful to obtain baseline chest CT for diagnosis
PET scanning not recommended for routine use
May help distinguish peripheral nerve sheath tumors from benign neurofibromas in patients with neurofibromatosis
For prediction of spread to bone and soft tissue with MRI of spine and CT of abdomen and pelvis recommended for high-risk patients with this histologic subtype
Diagnostic Approach
CT-guided core biopsy is desired diagnostic approach (accurate, safe, expeditious)
Incisional biopsy is more invasive than core biopsy
If utilized, incisional biopsies should be performed carefully
Subsequent definitive resection should be performed in mind
Tumor cells can potentially seed an incision
Thereby necessitating removal of scar at time of surgical resection
Important that biopsy approach does not transgress an uninvolved tissue plane
Would create situation where much more radical resection needed
Consequence of inappropriately placed incisional biopsies can be significant
Include need to perform more complex operations with potential for subsequent loss of function, LR, and death
Fine needle aspirate (FNA) cytology is not appropriate for malignant soft tissue disease
Does not yield enough tissue to establish initial diagnosis