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 could contradict diagnosis of hematoma, which typically presents with ecchymosis after trauma 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 pleomorphic (80-85%) giant cell (10%) inflammatory (<10%) 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 mass concerning for malignancy after clinical and radiological workup outcomes best results if done at the institution where definitive surgery will take place, under a multidisciplinary team wide surgical resection & radiation therapy indications standard of care in most cases radiation is an important adjunct to surgery decreasing local recurrence chemotherapy may be administered in some cases Neoadjuvant chemotherapy has shown improved 5-year recurrence-free survival and overall survival in tumors >10 cm outcomes 50-60% 5-year survival amputation indications when otherwise unable to resect tumor with negative margins resection would result in irreversible damage to major nerves patient comorbidities limit potential for recovery after limb-sparing surgery outcomes good prognosis in absence of metastatic disease Techniques Biopsy approach longitudinal incision transverse incisions are contraindicated due to a need for wider resection at time of surgery 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 use of tourniquet without exsanguination maintain meticulous hemostasis meticulous dissection to ensure wide margins, must confirm border free of disease with histology frozen section can be used to ensure margins are free of tumor radiation 50 Gy pre-operative and 66 Gy postoperative is the standard dose for soft-tissue sarcomas 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 frozen section can be used to ensure margins are free of tumor Prognosis Survival with treatment 50-60% 5-year survival