summary Undifferentiated Pleomorphic Sarcoma, previously known as malignant fibrous histiocytoma, is a high-grade, aggressive, malignant fibrogenic tumor. The condition is typically seen in patients 55-80 years of age who present with a slow-growing, painless mass. Diagnosis is made with a biopsy showing spindled, histiocytic, and multinucleated eosinophilic giant cells arranged in a storiform pattern arranged around small vessels. Treatment is usually wide-margin surgical excision with radiotherapy. Epidemiology Incidence 1-9/100,000 Demographics most common soft-tissue sarcoma in adults 55-80 years caucasian > African American male > female Anatomic location extremities (lower > upper) retroperitoneum Etiology Genetics mutations programmed cell death protein 1 (PD-1) expression in 30% Classification 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 Regional None Any IVB Any Any Present Any Presentation History may have history of trauma that draws attention to the mass Symptoms may present with fever common symptoms slow-growing, painless mass location lower > upper extremities > retroperitoneum Physical exam inspection painless soft tissue mass may be palpable lack of ecchymosis suggests an encapsulated mass login to view 1 more bullet neurovascular mass effect may cause neurovascular symptoms Imaging Radiograph indications obtain plain radiographs with orthogonal views for initial workup MRI 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 Studies Serum labs may present with hypoglycemia may present with elevated WBC Histology gross anatomy nodular, gray-white histology 3 subtypes login to view 3 more bullets spindled, histiocytic, and multinucleated eosinophilic giant cells cells arranged in storiform (cartwheel) pattern arranged around small vessels atypia and mitoses present Treatment Operative biopsy indications login to view 1 more bullet outcomes login to view 1 more bullet wide surgical resection & radiation therapy indications login to view 4 more bullets outcomes login to view 1 more bullet amputation indications login to view 3 more bullets 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 Wide resection & radiation therapy approach elliptical incision used to incorporate biopsy and drain sites technique resection login to view 4 more bullets radiation login to view 1 more bullet 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 Prognosis Survival with treatment 50-60% 5-year survival