summary Liposarcomas are a heterogeneous class of sarcomas with differentiation towards adipose tissue that consist of 5 different sub-types: well-differentiated, myxoid, round cell, pleomorphic, and dedifferentiated. The condition is typically seen in patients 50-80 years of age who present with a slow-growing, painless mass. Diagnosis is made with a biopsy showing immature lipoblasts with various cellular atypia depending on the sub-type. Treatment may be marginal excision for a well-differentiated liposarcoma. Wide surgical resection with radiation is indicated for intermediate and high-grade liposarcomas. Epidemiology Incidence liposarcomas are the second most common form of soft tissue sarcomas in adults Demographics occur in older individuals (50-80yrs) affect more males than females Anatomic location tend to occur deep to fascia more common in lower extremity than upper extremity common in retroperitoneum Etiology Pathophysiology the lipoblast (signet ring-type cell) is a hallmark of liposarcomas Genetics well-differentiated liposarcoma - amplification (MDM2) myxoid liposarcoma - translocation (12;16) Malignant potential metastasis risk correlates with grade/sub-type of liposarcoma low grade (well-differentiated) has a metastasis rate of < 1% intermediate grade (myxoid) has a metastasis rate of 10-30% high grade has a metastasis rate of > 50% Classification Histologic types liposarcoma types are related to the developmental stage of the lipoblasts from which they form all are from primitive mesenchymal cells types include well-differentiated same entity as atypical lipomatous tumor myxoid most common ~ 50% of all liposarcomas round cell pleomorphic dedifferentiated Imaging Plain Radiographs may show soft tissue calcification or ossification in well-differentiated liposarcomas MRI well-differentiated liposarcomas look similar to lipomas on MRI bright on T1, dark on T2 may show differences in rate of growth, stranding, size high-grade liposarcomas look similiar to other sarcomas on MRI dark on T1, bright on T2 although high grade liposarcomas appear fibrogenic, they may have 10% fat composition, so they appear dark on T1 and bright on T2 unlike a lipoma which images iso-intense to sub-cutaneous fat on all sequences CT Chest/Abd/Pelvis myxoid liposarcomas have a tendency for abnormal metastasis outside of the lungs therefore, histologic diagnosis of myxoid liposarcoma should be evaluated with CT chest/Abd/Pelvis Histology Characteristic histology immature lipoblasts (signet ring-type cells) mature adipocytes Well-differentiated liposarcoma (central/retroperitoneal) also known as atypical lipomatous tumor (extremities) low grade atypical lipoblasts, minimally cellular fatty stroma background stain for MDM2/CDK4 have ring chromosome 12 Myxoid liposarcoma low to intermediate grade proliferating lipoblasts upon a myxoid stroma matrix signet ring lipoblasts may occur Round cell liposarcoma poorly differentiated liposarcoma with characteristic small round blue cells Pleomorphic liposarcoma high-grade pleomorphic tumor giant lipoblasts with bizarre nuclei Dedifferentiated liposarcoma high-grade sarcoma adjacent to well-differentiated lipomatous lesion Treatment Operative marginal resection without radiotherapy indications well-differentiated liposarcoma outcomes low risk of local recurrence, metastasis extremely rare dedifferentiation risk of 2% in extremities and 20% in retroperitoneal lesions wide surgical resection with adjuvant radiotherapy indications intermediate grade liposarcomas high grade liposarcomas outcomes radiation decreases local recurrence chemotherapy may be beneficial in selected patients myxoid liposarcomas with >10% round cells have high likelihood of metastasis Prognosis Lipomas do not predispose a patient to a liposarcoma Well-differentiated liposarcomas exhibit < 10% local recurrence rates and <1% chance of metastasis and almost complete survival With appropriate treatment, intermediate and high grade liposarcomas show ~ 20% risk of local recurrence but they exhibit 5 year survival between 25 - 50%
QUESTIONS 1 of 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ18.159) A 56-year-old woman presents with a left gluteal mass. MRI is obtained and depicted in Figure A (T1-weighted). He undergoes a biopsy of the mass, and immunohistochemistry stains positive for the MDM2 amplification. Histology is depicted in Figure B. Which of the following is the best treatment? QID: 213055 FIGURES: A B Type & Select Correct Answer 1 Amputation 0% (9/1884) 2 Chemotherapy 1% (28/1884) 3 Radiotherapy 2% (33/1884) 4 Marginal resection 55% (1043/1884) 5 Wide resection 40% (759/1884) L 4 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (OBQ18.87) A 71-year-old male presents with a large mass on his right thigh. An MRI and biopsy are performed and are shown in Figures A-C. What is the genetic basis of the condition, and what is the next best step in treatment? QID: 212983 FIGURES: A B C Type & Select Correct Answer 1 MDM2 amplification; marginal resection without radiation 44% (867/1964) 2 t(2;13) translocation; marginal resection without radiation 6% (112/1964) 3 MDM2 amplification; marginal resection with radiation 15% (303/1964) 4 t(2;13) translocation; wide resection with radiation 13% (257/1964) 5 t(12;16) translocation; wide resection with radiation 21% (405/1964) L 4 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ13.25) A 50-year-old male presents with a painless thigh mass that has been growing in size. A representative MRI sequence, gross specimen and histologic evaluation are shown in Figures A, B and C respectively. What is the most likely diagnosis and associated corresponding chromosomal translocation? QID: 4660 FIGURES: A B C Type & Select Correct Answer 1 Alveolar rhabdomyosarcoma; t(2;13) 4% (172/4004) 2 Fibrosarcoma; t(11;22) 1% (55/4004) 3 Pleiomorphic undifferentiated sarcoma; t(12;16) 2% (98/4004) 4 Synovial sarcoma; t(X;18) 3% (117/4004) 5 Myxoid liposarcoma; t(12:16) 88% (3522/4004) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic (SBQ11OS.150.1) Figures A, B, and C are the MRI scans and biopsy specimen of a 53-year-old man who has had left leg pain and swelling for the past 9 months. What is the most likely diagnosis? QID: 210698 FIGURES: A B C Type & Select Correct Answer 1 Myxoid liposarcoma 60% (1440/2403) 2 Synovial sarcoma 17% (418/2403) 3 Atypical lipomatous tumor 7% (170/2403) 4 Pigmented villonodular synovitis 1% (33/2403) 5 Myxoma 13% (320/2403) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ07.70) A 40-year-old female presents with a painless enlarging left thigh mass. Radiograph, T1, and T2 MRI images are shown in Figures A through C. Biopsy specimen is shown in Figure D. What is the most likely diagnosis? QID: 731 FIGURES: A B C D Type & Select Correct Answer 1 Lipoma 2% (41/2291) 2 Liposarcoma 86% (1978/2291) 3 Hemangioma 0% (11/2291) 4 Chondrosarcoma 1% (18/2291) 5 Leiomyosarcoma 10% (235/2291) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic (OBQ06.207) A 56-year-old male presents with a mass in his thigh that has been slowly growing over the past year. Femur radiograph, sagittal T1 and T2 weighted MRI scans, and histology section taken from an open biopsy are shown in Figures A through D. What is the diagnosis? QID: 218 FIGURES: A B C D Type & Select Correct Answer 1 Lipoma 3% (36/1390) 2 Synovial sarcoma 1% (13/1390) 3 Undifferentiated pleomorphic sarcoma 10% (134/1390) 4 Liposarcoma 86% (1190/1390) 5 Hemangiopericytoma 1% (13/1390) L 1 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic
All Videos (0) Podcasts (2) Pathology⎪Liposarcoma Pathology - Liposarcoma Listen Now 12:16 min 10/16/2019 224 plays 5.0 (1) Question Session⎪Liposarcoma & Amputations Orthobullets Team Pathology - Liposarcoma Listen Now 32:47 min 11/8/2019 49 plays 0.0 (0)