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Liposarcoma


Editor-in-Chief: Debra L. Zynger, M.D.
Swapnil U. Rane, M.D.

Last author update: 1 August 2015
Last staff update: 5 June 2023

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PubMed Search: Liposarcoma [title] testis

Swapnil U. Rane, M.D.
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Table of Contents
Epidemiology | Sites | Pathophysiology / etiology | Clinical features | Diagnosis | Laboratory | Radiology images | Prognostic factors | Case reports | Treatment | Clinical images | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Differential diagnosis | Additional references
Cite this page: Rane S. Liposarcoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/testisliposarcoma.html. Accessed April 18th, 2024.
Epidemiology
  • Rare; mean 63 years, range 41 to 87 years but younger patients have been reported
  • Most common malignant tumor involving the spermatic cord (46%) (Urol Oncol 2014;32:52)
  • Paratesticular liposarcomas account for ~12% of all liposarcomas
  • Well differentiated tumors tend to recur, often late yet have a good outcome; dedifferentiated tumors have metastatic potential
Sites
  • Usually arise from spermatic cord; also testicular tunica; rarely epididymis
Pathophysiology / etiology
  • Recurrent molecular abnormalities have been detected in liposarcomas, which differ between each subtype
  • Well differentiated liposarcoma is characterized by the presence of amplification involving 12q13-q15, which can be identified using FISH or CGH
  • Myxoid liposarcoma is characterized by the presence of t(12;16)(q13;p11), which results in the FUS-CHOP gene fusion that is present in over 95% of cases
    • Most often, the amino terminal domain of FUS (also known as TLS) is fused to C/EBP homologous protein (CHOP, also known as DDIT3 or GADD153)
    • In rare cases, an alternative translocation event is found, t(12;22)(q13;q12), that results in formation of the novel fusion oncogene where EWS takes the place of FUS
    • RET, IGF1R and IGF2 are highly expressed in MLPS and promote cell survival through both the PI3K/Akt and Ras-Raf-ERK/MAPK pathways (Hum Pathol 2009;40:1244, Nat Clin Pract Oncol 2007;4:591) and represent potential therapeutic targets
  • Pleomorphic liposarcoma shows complex chromosomal abnormalities with gains in 1p, 1q21-q32,2q, 3p, 3q, 5p12-p15, 5q, 6p21, 7p, 7q22 and losses involving 1q, 2q, 3p, 4q, 10q, 11q, 12p13, 13q14, 13q21-qter, 13q23-24
Clinical features
  • Painless scrotal mass of longstanding duration is the most common presentation
  • Rarely is of recent duration
  • May present as an inguinal hernia, hydrocele, hematocoele or other testicular tumor
Diagnosis
  • Diagnosis requires histological examination
  • Clinical differentiation from other testicular and paratesticular sarcomas is not possible
Laboratory
  • No specific laboratory abnormality is known
  • Serum markers for germ cell tumors and sex cord tumors are negative
Radiology images

Images hosted on other servers:

Nonhomogeneous right scrotal mass

No evidence of tissue infiltration

Large heterogenous extratesticular mass

CT of paratesticular liposarcoma presenting as hernia

Prognostic factors
  • Recurrence of well differentiated paratesticular liposarcoma after complete resection is extremely rare (Malays J Med Sci 2013;20:95)
  • Recurrence rate is < 10% when resection margin is 10 mm or greater
  • Risk factors for local recurrence / progression:
    • High grade tumor morphology
    • Large tumor size ( > 5 cm)
    • Inadequate / suboptimal resection
Case reports
Treatment
  • Usual treatment is orchidectomy through inguinal approach, with adequate margins
  • Elective inguinal node dissection is not indicated
  • Cases with a margin < 10 mm or with residual tumor may benefit from radiotherapy; liposarcoma is radiosensitive and the well differentiated subtype is most sensitive
  • Radiotherapy also useful for unresectable cases
  • Role of chemotherapy (ex: doxorubicin) is debated; no clear benefit has been shown
  • Surgical excision is also the cornerstone of management of recurrent cases
Clinical images

Images hosted on other servers:

Scrotal mass at presentation

Tumor after chemotherapy

Gross description
  • Tumors are usually large, appear to be relatively circumscribed
  • Cut surface may be yellow, fatty with interspersed fibrous septae or may be uniformly firm and white
  • Areas of necrosis and hemorrhage may be seen in high grade tumors
Gross images

Images hosted on other servers:

Tumor mass

Yellow and myxoid areas

White yellow to red brown cut surface, marked necrosis

Right paratesticular mass with solid, yellow white, fatty, myxoid areas

Grossly firm tumor

Microscopic (histologic) description
  • Mature adipocytes, atypical spindle cells and multivacuolated lipoblasts embedded in a loose myxoid to dense fibrous stroma
  • All variants of liposarcoma may be seen; well differentiated or dedifferentiated liposarcomas are most common
  • Heterologous leiomyosarcomatous or osteosarcomatous differentiation (Am J Surg Pathol 2002;26:742) and osseous metaplasia (Case Rep Urol 2015;2015:965876) have been reported but their presence does not appear to affect prognosis
  • Pleomorphic liposarcoma accounts for < 5% of cases and is characterized by MFH-like histology with a disorderly pattern, pleomorphic cells, multinucleated bizarre giant cells and lipoblasts
  • Giant lipoblasts have enlarged globular or angular hyperchromatic nuclei
  • Other variants have also been reported
Microscopic (histologic) images

Images hosted on other servers:

Well differentiated liposarcoma:
 

Atypical spindle cells and lipoblasts

   

Mature adipocytes and lipoblasts



Well differentiated with dedifferentiated component:

Hypercellular stroma with atypical adipocytes

Atypical adipocytes with enlarged nuclei



Dedifferentiated with leiomyosarcomatous component:

H&E

MDM2+, CDK4+, alpha smooth muscle actin+, desmin+



Myxoid liposarcoma:

Lipoblasts contain lipid vacuoles

Plexiform arrangement of capillaries

Positive stains
  • MDM2, CDK4 (usually negative in myxoid / round cell and spindle subtypes)
  • S100
  • Heterologous elements may show positivity for desmin, actin, etc., based on the differentiation and dedifferetiated tumors have variable reactivity
  • STAT6 may rarely be positive (reported in dedifferentiated liposarcoma)
Negative stains
Differential diagnosis
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