Pathology Outlines - Testis and epididymis

Testis and epididymis
Spermatic cord tumors
Liposarcoma

Author: Swapnil U. Rane, M.D. (see Authors page)
Editorial Board review: Debra Zynger, M.D.

Revised: 24 May 2017, last major update August 2015

Copyright: (c) 2003-2015, PathologyOutlines.com, Inc.

PubMed Search: Liposarcoma [title] testis

Table of Contents

Cite this page: Testis and epididymis - Liposarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/testisliposarcoma.html. Accessed July 15th, 2017.

See also Liposarcoma - spermatic cord

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

This amplification is associated with the occurrence of supernumerary ring chromosomes or giant rod chromosomes
The 12q13-q15 region contains multiple genes implicated in the pathogenesis of liposarcoma, including MDM2, CDK4, HMGA2, TSPAN31, OS1, OS9, CHOP, STAT6 and GLI (Virchows Arch 2010;456:277, Genes Chromosomes Cancer 1999;24:30, Genes Chromosomes Cancer 1995;14:8, Cancer Genet Cytogenet 1997;99:14, Mod Pathol 2014;27:1231)

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

60% of pleomorphic liposarcoma show deletion of 13q14.2-q14.3, which houses the RB1 gene
MAD2 gene is also commonly amplified in pleomorphic liposarcoma (Cancer Res 2007;67:6626, Curr Biol 2010;20:328)

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

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 10mm or greater
Risk factors for local recurrence/progression:
- High grade tumor morphology
- Large tumor size (>5cm)
- Inadequate/suboptimal resection

Case reports

23 year old man with paratesticular myxoid liposarcoma (Rare Tumors 2010;2:e23)

46 year old man with paratesticular myxoid / round cell liposarcoma (Pathol Res Pract 2013;209:124)

50 year old man with recurrence of paratesticular liposarcoma (World J Surg Oncol 2014;12:276)

50 year old man with paratesticular liposarcoma masquerading as a testicular tumor (J Clin Diagn Res 2014;8:165)

65 year old man with bilateral paratesticular liposarcoma (J Surg Tech Case Rep 2014;6:15)

77 year old man with paratesticular dedifferentiated liposarcoma with leiomyosarcomatous differentiation (Diagn Pathol 2013;8:142)

Mixed paratesticular liposarcoma with osteosarcoma elements (Clin Transl Oncol 2010;12:148)

Well differentiated inflammatory liposarcoma (Am J Surg Pathol 1997;21:518)

Dedifferentiated liposarcoma (Am J Surg Pathol 1994;18:1213)

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

Non homogeneous right scrotal mass

No evidence of tissue infiltration

Large heterogenous extratesticular mass

Scrotal mass at presentation

Tumor after chemotherapy

CT of paratesticular liposarcoma presenting as hernia

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

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

Well differentiated liposarcoma