Summary Soft tissue sarcomas are rare, malignant tumors comprising of a variety of subtypes distinguished by histological findings. The condition usually presents in patients > 15 years old with a slow-growing, painless soft tissue mass. Diagnosis is made by biopsy and histological findings. Treatment usually involves mass excision and radiation therapy. Epidemiology Incidence 12,000 new cases/year in the United States 4,700 deaths/year in the United States Demographics males > females 85% occur in patients >15 years old Anatomic location 60% occur in extremities 44% occur in the thigh Etiology Genetics classic translocations t(X;18); SYT-SSX fusion login to view 1 more bullet t(2:13) login to view 1 more bullet t(12;16)(q13:p11) login to view 1 more bullet Associated conditions neurofibromatosis type-1 malignant peripheral nerve sheath tumor (MPNST) Stuart-Treves syndrome angiosarcoma chronic lymphedema angiosarcoma Classification Classification of STS is based on histology, with over 50 types recognized all STS have the same presentation, imaging, differential diagnosis, and treatment histologic findings and molecular signatures are used to distinguish individual types commonly tested soft tissue sarcomas include undifferentiated pleomorphic sarcoma (UPS; previously malignant fibrous histiocytoma) malignant peripheral nerve sheath tumor (MPNST) synovial sarcoma liposarcoma rhabdomyosarcoma fibrosarcoma leiomyosarcoma epithelioid sarcoma angiosarcoma dermatofibrosarcoma protuberans clear cell sarcoma alveolar soft part sarcoma (ASPS) soft tissue sarcomas that metastasize to lymph nodes (when it RACES to the lymph nodes) Rhabdomyosarcoma, Angiosarcoma, Clear cell sarcoma, Epithelioid sarcoma, Synovial sarcoma Overall, only 5% of soft tissue sarcomas metastasize to lymph nodes AJCC staging system is used for interdisciplinary communication AJCC Staging System for Soft Tissue Sarcoma of the Extremity or Trunk Stage Size Lymph Node Involvement Metastasis Grade IA < 5 cm None/unknown None Low IB > 5 cm None/unknown None Low II < 5 cm None/unknown None Intermediate/high IIIA 5-10 cm None/unknown None Intermediate/high IIIB > 10 cm None/unknown None Intermediate/high IVA Any Any None Any IVB Any Any Any Any Presentation History may have a history of trauma that draws attention to the mass Symptoms slow growing, painless mass incidental trauma often draws attention to mass rapid growth usually suggests a higher grade Physical exam inspection mass may be palpable lack of ecchymosis suggests an encapsulated mass login to view 1 more bullet palpable soft tissue lesion differentiating whether a mass is above or below fascia has prognostic importance poor prognostic indicators include >5cm, deep to fascia, and immobile can be confused with more common pathology lipoma hematoma desmoid tumor nerve sheath tumors assess local lymph nodes Imaging Radiographs indications obtain plain radiographs in at least two planes for initial workup findings may show soft tissue shadow or mineralization (most commonly with synovial sarcoma) CT chest indications obtain to assess for metastatic disease an exception is that a CT chest/abdomen/pelvis is indicated for myxoid liposarcoma MRI with contrast indications mandatory to evaluate soft tissue lesions in the extremities and determine treatment algorithm findings T1: low signal intensity (isointense with muscle) T2: high signal intensity IV gadolinium: peripheral enhancing zone and non-enhancing necrotic center can be diagnostic for the following benign lesions if MRI is diagnostic and the mass is benign and symptomatic, then it can be removed without a biopsy lipoma ganglion cyst neurilemoma (schwannoma) intramuscular myxoma indeterminate MRI if MRI is indeterminate or suggestive of sarcoma, then a core needle or open biopsy must be obtained before further treatment is initiated be cautious of a "hematoma" without associated trauma because they can have similar appearances PET evolving indications particularly useful for sarcomas that metastasize to lymph nodes Studies Histology determined by type of sarcoma undifferentiated pleomorphic sarcoma malignant peripheral nerve sheath tumor synovial sarcoma liposarcoma rhabdomyosarcoma fibrosarcoma leiomyosarcoma epithelioid sarcoma angiosarcoma dermatofibrosarcoma protuberans Differential Differentiate from benign soft tissue masses with MRI and biopsy Hematoma Lipoma Intramuscular Myxoma Hemangioma of Soft Tissue Calcifying Aponeurotic Fibroma Plantar Fibromatosis (Ledderhose Disease) Extra-abdominal Desmoid Tumor Nodular Fasciitis Neurofibroma Neurilemmoma Neuroma Treatment Operative biopsy indications login to view 1 more bullet outcomes login to view 3 more bullets wide surgical resection & radiation therapy indications login to view 10 more bullets outcomes login to view 1 more bullet amputation indications login to view 4 more bullets outcomes login to view 1 more bullet surgical resection of lung metastases indications login to view 1 more bullet outcomes login to view 1 more bullet Techniques Biopsy approach longitudinal incision login to view 1 more bullet technique use anatomic route that limits contamination of compartments and neurovascular structures maintain meticulous hemostasis use knife or curette to remove tissue drains should be placed distal and in line with the surgical incision to allow removal of drain site with extensile incision requires a specialized pathologist to interpret the results accurately Wide resection & radiation therapy approach elliptical incision used to incorporate biopsy and drain sites technique resection login to view 4 more bullets consideration of nearby neurovascular and bony structures login to view 5 more bullets radiation login to view 2 more bullets Amputation approach level and incision guided by advanced imaging to ensure negative margins technique use of tourniquet without exsanguination maintain meticulous hemostasis meticulous dissection to ensure wide margins must confirm border free of disease with histology login to view 1 more bullet Surgical resection of lung metastases technique wedge resection lobectomy Complications Radiation-induced pre-operative radiotherapy is associated with a 20-30% risk of wound complications Risk of desquamation, delayed wound healing, infection post-operative radiotherapy is associated with greater radiation-induced morbidity and an increased risk of radiation-induced sarcoma Risk of later fibrosis, post-radiation fracture, possible secondary sarcoma no difference in oncologic outcome between preoperative and postoperative radiation late effects: fibrosis, post-radiation fracture, possible secondary sarcoma post-radiation sarcoma Recurrence local recurrence <10% with radiation and surgery following resection, the most common location for recurrence of a low-grade STS is locally most recurrences occur in the first 5 years, but patients require indefinite follow-up Unplanned excision the most common mistake in treatment of soft tissue sarcomas 74% have residual disease CT chest, abdomen, pelvis to exclude metastasis MRI of the limb to determine the degree of contamination, post-operative changes, and to assess margins revision surgery necessary for all unplanned excisions limb salvage + radiation therapy amputation unplanned excision is associated with higher plastic reconstruction of the affected region Prognosis Natural history of disease often slow-growing painless mass metastasis is most commonly to the lung 5% lymph node metastasis (most commonly epithelioid, synovial, angiosarcoma, rhabdomyosarcoma, clear cell) Prognostic variables tumor stage is most important prognostic factor poor prognostic factors include high-grade metastatic disease size > 5 cm tumor location below the deep fascia delay in diagnosis unplanned excision login to view 2 more bullets Survival with treatment low-grade disease: 90% 5-year survival stage II and III disease: 50-75% 5-year survival stage IV: 15% 5-year survival patients with advanced disease have median survival of 12-18 months