CASE REPORTS

Mediastinal Lipoblastomatosis: Report of aCase with Complex Karyotype and Review ofthe LiteratureNASIR K. AMRA

*AND SAMIR S. AMR

Pathology Services Division, Dhahran Health Center, Dhahran, Saudi Arabia

Received September 5, 2008; accepted February 3, 2009; published online February 4, 2009.

ABSTRACTLipoblastoma or lipoblastomatosis is an uncommon fatty

tumor seen in children up to the age of 5 years, with very

rare exceptions above that age. It usually occurs in the

extremities, but it can arise in other anatomical sites,

including the head and neck area, trunk, mediastinum,

mesentry, and retroperitoneum. We report a 9-month-old

boy with mediastinal lipoblastomatosis showing unusual-

ly complex chromosomal aberrations. Five years follow-

ing surgical excision that was incomplete as a result of the

tumor’s proximity to major blood vessels, the patient

developed a recurrence of the tumor in the mediastinum

with extension to the neck and spinal dura. We present a

review of the literature related to mediastinal lipoblas-

toma and lipoblastomatosis and the chromosomal abnor-

malities of these tumors.

Key words: fatty tumors, lipoblastoma, lipoblastomato-

sis, liposarcoma, mediastinal tumors, tumor cytogenetics

INTRODUCTION

Since its 1st description in 1958 by Vellios and colleagues

[1], lipoblastomatosis has come to mean a benign

embryonal fatty tumor affecting children, with a predelic-

tion to the male gender. In 1973, Chung and Enzinger [2],

in a review of 35 cases, suggested that the term

lipoblastoma be used for the circumscribed type and that

the term lipoblastomatosis be used for the diffuse

infiltrative or multicentric type. The tumor arises in many

different anatomic locations and can have morphologic

features that could be confused with liposarcoma [2],

lipoma [3], fibrolipoma [4], lipofibromatosis [5], low-

grade fibromyxoid sarcoma [6], or even neurothekeoma

[7]. Recently, a nonrandom distinct cytogenetic abnormal-

ity characterized by 8q11-q24 chromosomal aberration has

been demonstrated in lipoblastomas [8–11]. We report a

rare case of mediastinal lipoblastomatosis with complex

cytogenetic karyotype, and we review the medical

literature. We shall use the term lipoblastoma to encompass

lipoblastoma and lipoblastomatosis unless we are discuss-

ing specifically the difference between the 2 entities.

CASE REPORT

A 9-month-old male infant presented with a 1-week history

of nonproductive cough and noisy exhalation with no

fever, vomiting, or diarrhea. The patient had a history of

intermittent lip cyanosis during crying. Anterior-posterior

and lateral chest X-rays demonstrated an upper mediastinal

mass that was pushing the trachea to the right, with a very

narrow airway entry. A chest computed tomographic scan

demonstrated a large septate fatty mass measuring 7 3 7 3

4.6 cm that extended from the level of the lower neck to the

anterior mediastinum and into the middle mediastinum,

displacing major blood vessels, trachea, and thymus to the

right. The patient underwent thoracotomy, and a large

portion of the tumor was resected, as was the adjacent

thymus gland. A portion of the tumor was not resected

because of its proximity to major blood vessels. Postop-

eratively, the patient displayed left diaghragmatic paralysis

and had a residual tumor measuring 3.5 3 3 3 3 cm.

Over a follow-up period of 5 years, magentic

resonance imaging scans and physical evaluations

demonstrated regrowth of the tumor, which grew to

measure 6.1 3 4.8 3 4.6 cm within the mediastinum,

with extension to the spinal dura but without spinal cord

invasion. The tumor also extended into the left sterno-

cleidomastoid and scalene muscles. Five years after the

operation, the patient does not have any persistant

physical discomfort or symptoms from this tumor.*Corresponding author, e-mail: nasir.amra@aramco.com

Pediatric and Developmental Pathology 12, 469–474, 2009

DOI: 10.2350/08-09-0525.1

ª 2009 Society for Pediatric Pathology

PATHOLOGIC FINDINGS

An intraoperative consultation (frozen-section) diagnosis

of lipoblastoma was rendered on a small biopsy of the

tumor. The subsequently resected tumor weighed 68 g

and consisted of nodular, soft, tan tissue that was not

encapsulated (Fig. 1A).

Histological examination revealed mature adipocytes

with a lobulated architecture and peripheral spindle cell

proliferation (Fig. 1B). There were spindle cell areas with

associated myxoid stroma (Fig. 1C) and multivacuolated

lipoblasts (Fig. 1D). Focal dystrophic calcification with

fat necrosis was noted.

Chromosomal analysis of the tumor along with

fluorescent in situ hybridization (FISH) using multicol-

ored probes for all human chromosomes demonstrated a

Figure 1. (A) Partially resected lipoblastomatosis weighing68 g. (B) Fatty tumor with peripheral spindle cell prolifera-tion (hematoxylin and eosin, objective magnification 310).(C) An area of abundant myxoid stroma (hematoxylin andeosin, objective magnification 320). (D) An area of lipoblasts(hematoxylin and eosin, objective magnification 340).

Figure 2. GTG-banding (A) and fluorescent in situ hybrid-ization (FISH) (B) using multicolored probes for all humanchromosomes demonstrate a complex karyotype: 46,XY,der(2)inv(2)(q31q35)t(2;5;14;10)(?qter;q11.2;q32;p11.2),der(5)t(2;5;14;10),inv(7)(q21.2q22), del(8)(q13q24.1),der(10)t(2;5;14;10),der(14)t(2;5;14;10)ins(5;8)(q31;q13q24.1).

470 N.K. AMRA AND S.S. AMR

quite complex karyotype: 46,XY,der(2)inv(2)(q31q35)

t(2;5;14;10)(?qter;q11.2;q32;p11.2),der(5)t(2;5;14;10),

inv(7)(q21.2q22), del(8)(q13q24.1),der(10)t(2;5;14;10),

der(14)t(2;5;14;10)ins(5;8)(q31;q13q24.1) (20 cells ana-

lyzed, 3 cells karyotyped). This karyotype includes the

characteristic rearrangement involving chromosome 8

that is seen with lipoblastoma, along with additional

complex chromosomal abnormalities (Fig. 2).

DISCUSSION

Lipoblastoma is typically circumscribed and located in

the superficial soft tissues, simulating a lipoma. The more

diffuse, infiltrative form is called lipoblastomatosis. This

is a slow-growing tumor with a male predilection that can

compress and displace adjacent structures, as it did in this

patient. It typically arises in the soft tissue of the

extremities and trunk, but rarely it can involve the

mediastinum and retroperitoneum. Aggregating published

large institutional reviews [2,12–15] of this entity

indicates that only 1% (1 of 102) of cases of this tumor

involve the mediastinum. This single case of mediastinal

lipoblastomatosis was reported in a series by Chung and

Enzinger [2] involving 35 total cases of lipoblastoma/

lipoblastomatosis. In addition, there are 20 individual

case reports of mediastinal lipoblastoma (14 cases) and

lipoblastomatosis (6 cases) [16–34] (Table 1). Cases

involving the chest wall, the lungs, or the pleural cavities

are not included in this review. The age range for cases of

mediastinal lipoblastoma is 4 months to 6 years (mean,

32.9 months). On the other hand, the age range for cases

of mediastinal lipoblastomatosis is 3 months to 20 months

(mean, 13 months). This mean age difference at initial

diagnosis between lipoblastoma and lipoblastomatosis

was observed in a large series [12] that comprised cases

from various anatomic sites. There was no preponderance

of males (10 cases) over females (10 cases) in these cases.

In most series [2,12] of lipoblastoma/lipoblastomatosis,

Table 1. Mediastinal lipoblastoma/lipoblastomatosis reported in the literature

Author(s) Age Sex Type Follow-up Remarks

Chung and Enzinger [2] 2 y F Lipoblastomatosis 4.5 y NED Presented with dyspnea and tumor extending

into the neck

Tabrisky and colleagues [16] 11 m M Lipoblastomatosis 18 m NED 500-g mass, filled right hemithorax

Dudgeon and Haller [17] 3 m F Lipoblastomatosis 2.5 y NED 7.5 3 6.5 cm, displaced the heart to the right

Sancho-Cerquella and

colleagues [18]

6 m M Lipoblastoma 11 y NED

Sancho-Cerquella and

colleagues [18]

20 m F Lipoblastomatosis 2 y NED

Marques Gubern and

colleagues [19]

12 m NA Lipoblastomatosis NA Diaphragmatic involvement

Whyte and Powell [20] 11 m M Lipoblastoma NA Chest wall involvement

Federici and colleagues [21] 14 m M Lipoblastoma NA Respiratory stridor and dyspnea on the supine

Ko and colleagues [22] 17 m M Lipoblastoma NA Intraspinal extension with formation of a

long segment of extradural mass

Irgau and McNicholas [23] 6 y F Lipoblastoma NA Left innominate vein and phrenic nerve were

sacrificed in total resection

Broeders and colleagues [24] 6 y M Lipoblastoma NA 10.5 3 5.5 3 2.5 cm, right paravertebral

gutter

Park and colleagues [25] 4 m F Lipoblastoma NA Tumor is related to pleura and right lung is

displaced and collapsed

Ng and colleagues [26] 3 y F Lipoblastoma NA 556-g tumor

Ching and colleagues [27] 4 y F Lipoblastoma 12 m NED Lobulated homogeneous anterior mediastinal

mass (8 3 5 cm) in the right hemithorax

Sharma and colleagues [28] 2 y F Lipoblastoma 4 m NED Suprascapular mass with spinal epidural

extension

Li and colleagues [29] 9 m F Lipoblastoma NA 15 3 12 cm, filling left hemithorax

Rao and colleagues [30] 6 m M Lipoblastomatosis NA Dumbbell-shaped tumor involving both

hemithoraces

Binay and Shan [31] 6 y M Lipoblastoma 6 m Giant mass, 22 3 22 3 15 cm, 996 g

Moholkar and colleagues [32] 2.5 y F Lipoblastoma 91 m NED

Dogan and colleagues [33] 14 m M Lipoblastomatosis NA Extension to the neck and associated with

paraparesis

Guillen-Quesada and

Costa-Clara [34]

27 m M Lipoblastoma NA Tumor extended to spinal epidural space

from C7 to D9

Amra and Amir (current

study)

9 m M Lipoblastomatosis 5 y Tumor recurred locally with extension to the

spinal dura

y indicates years; m, months; F, female; M, male; NA, not available; NED, no evidence of disease.

MEDIASTINAL LIPOBLASTOMATOSIS 471

there had been a preponderance of males over females.

Several patients presented with symptoms related to

airway obstruction, including cough, tachypnea, and

circumoral cyanosis [2,16,21,25,29], and a few masses

attained large size [16,17,24,29,31]. In one case, the

tumor weighed 996 g [31]. In another case, the tumor

weighed 500 g, and it filled the right hemithorax [16].

Our case involved a recurrence with extension to the

spinal canal. Several cases of mediastinal lipoblastoma

[22,28,34] or lipoblastomatosis [33] have been associated

with extension to the spinal canal, with associated

neurological manifestations, such as paresis. Other cases

of lipoblastoma arising in other anatomical locations,

such as the right side of the neck [35] or the back [36],

have also been associated with intraspinal extension.

Histologically, lipoblastoma demonstrates a range of

adipocyte maturation encompassing spindle-shaped mes-

enchymal cells, unilocular lipoblasts, multivacuolar

lipoblasts, and mature adipocytes. Myxoid change and a

plexiform vascular network are other characteristic

features of this tumor [37].

The differential diagnosis of fat-containing tumors of

the mediastinum includes myxoid liposarcoma, teratoma

composed mostly of fat (when only a small biopsy is

taken), lipoma, fibrolipoma, thymolipoma, hibernoma, or,

rarely, low-grade fibromyxoid sarcoma (when normal fat

is incorporated within this fibrous tumor) [38]. Thymo-

lipoma can be distinguished histologically from the other

tumors by the presence of thymic parenchyma with well-

developed Hassall corpuscles [39]. The cytogenetic

findings help distinguish lipoblastoma (associated with

rearrangements of chromosome 8q11-13) from myxoid

liposarcoma (associated with chromosome t[12;16]),

lipomas, and fibrolipomas (associated with chromosomal

aberrations 12q13-15 and 6p21-23) as well as hibernoma

(associated with aberrations in chromosomal band 11q13)

[40,41]. The lack of cellular atypia in lipoblastoma and

the typical age incidence of myxoid liposarcoma (30–60

years) versus lipoblastoma (typically seen before the age

of 3 years) are additional helpful differentiating features.

Lipoblastoma is lobulated, a feature not often seen in

liposarcoma. Liposarcoma may contain microcystic areas,

which are not seen in lipoblastoma. Interestingly, low-

grade fibromyxoid sarcoma displays chromosomal aber-

ration of chromosome 16, as does liposarcoma. How-

ever, low-grade fibromyxoid sarcoma is associated with

t(7;16) (q32-34;p11) producing a FUS/CREB3L2

fusion gene. Moreover, the lack of lipoblasts and the

histologic architecture of alternating areas of bland

spindle cells with collagen deposits and myxoid areas

distinguish this tumor from lipoblastoma or myxoid

liposarcoma [42,43].

Immunohistochemical stains have a limited role in

the above differential diagnosis of fatty tumors of the

mediastinum. However, a recent abstract [44] has

demonstrated in a small study that desmin immunohisto-

chemical stain can help differentiate lipoblastoma from

other fatty tumors. The spindled cells in lipoblastoma are

diffusely positive for desmin, in contrast to negative or

rare focal positivity in lipoma, lipofibroma, myxoid

liposarcoma, and well-differentiated liposarcoma [44].

Two case reports [45,46] illustrate the utility of

cytogenetics in helping differentiate lipoblastoma from

liposarcoma in atypical clinical presentations of fatty

tumors. One report involves a 14-year-old girl with a

lipomatous tumor of the right thigh that proved to be well-

differentiated liposarcoma by FISH studies [45]. Another

case involves a 23-year-old male with lipoblastoma in the

right thigh, as proven by karyotyping and FISH studies

[46]. More recently, 6 cases of lipoblastoma in patients

ranging from 14 to 24 years of age were reported [47],

with results of FISH demonstrating rearrangements of the

PLAG1 region in 2 cases and polysomy for chromosome

8 in 3 other cases. None of the tumors had amplification

of MDM2 or CDK4. The authors [47] concluded that

lipoblastoma can rarely occur in young adults and should

enter into the differential diagnosis of ‘‘atypical’’ fatty

tumors in adults.

Complex cytogenetic abnormalities in lipoblastoma

have not been reported frequently. Similar complex

cytogenetic abnormalities have been seen in a case report

[48] of an intrascrotal lipoblastoma. While this case

demonstrates chromosomal aberrations (including addi-

tions and deletions) in 6 chromosomes, the intrascrotal

lipoblastoma involved 11 chromosomes. Only 3 chromo-

somal aberrations are shared between the 2 cases

(involving chromosomes 7, 8, and 10). It is unclear

whether these cases in this subset of lipoblastoma, with

their complex cytogentic findings, have a different

prognosis.

Cytogenetic karyotyping of lipoblastoma has shown

consistent chromosomal breakpoints involving 8q11-13.

The PLAG1 gene, located in 8q12, has been shown to be

involved in the chromosomal rearrangements that produce

the fusion genes HAS2/PLAG1 and COL1A2/PLAG1.

These fusion genes leads to transcriptional upregulation

of the fusion gene products through a promotor-swapping

mechanism. Polysomy of chromosome 8 is another

proposed [9,37,49] mechanism for increasing PLAG1

production in lipoblastoma.

PLAG1 is a zinc-finger transcription factor protein

that is usually expressed at very low levels postnatally. It

was first discovered as an oncogenic factor in pleomor-

phic adenoma (associated with t[3;8][p21;q12]) and has

been demonstrated to be elevated in hepatoblastoma, 20%

of acute myelogenous leukemia cases, uterine leiomyo-

ma, leiomyosarcomas, and smooth muscle tumors.

PLAG1 appears to mediate its oncogenic potential via

the insulin-like growth factor 2 signaling pathway; the

activation of which in turn increases mitogenesis via the

MAPK signaling pathway mediated by insulin-like

growth factor receptor (IGF-1R) [50]. The recent

commercial availability of PLAG1 antibody raises the

possibility of detecting overexpression of PLAG1 by

immunohistochemical stain to aid in the diagnosis of

lipoblastoma.

472 N.K. AMRA AND S.S. AMR

Surgical excision is the treatment of choice, which

offers an excellant prognosis. There is a reported

recurrance rate of 9% to 22% among all lipoblastomas

[37]. Authors of one report [51] indicate that lipoblastoma

may spontaneously resolve with time and suggest that a

‘‘wait and see’’ approach can be pursued in cases in

which complete excision of the lesion cannot be

performed without mutilation or significant morbidity.

ACKNOWLEDGMENTS

The authors acknowledge the use of Saudi Aramco

Medical Services Organization (SAMSO) facilities for the

research data utilized in this manuscript. They acknowl-

edge as well Robert Jenkins of the Mayo Medical

Laboratories for his assistance with cytogenetic analysis.

Opinions expressed in this article are those of the authors

and not necessarily of SAMSO.

REFERENCES1. Vellios F, Bacz JM, Shumacker HB. Lipoblastomatosis: a tumor of

fetal fat different from hibernoma. Report of a case, with

observations of embryogenesis of human adipose tissue.

Am J Pathol 1958;34:1149–1159.

2. Chung EB, Enzinger FM. Benign lipoblastomatosis. An analysis of

35 cases. Cancer 1973;32:482–492.

3. Morerio C, Nozza P, Tassano E, et al. Differential diagnosis of

lipoma-like lipoblastoma. Pediatr Blood Cancer 2009;52:132–134.

4. Canto C, Zapata S, Wise S, Carvalho D. Lipofibroma of the neck in

children: an unusual diagnosis with special surgical implications.

Otolaryngol Head Neck Surg 2007;137:976–978.

5. Fetsch JF, Miettinen M, Laskin WB, Michal M, Enzinger FM. A

clinicopathologic study of 45 pediatric soft tissue tumors with an

admixture of adipose tissue and fibroblastic elements, and a

proposal for classification as lipofibromatosis. Am J Surg Pathol

2000;24:1491–1500.

6. Dawamneh MF, Amra NK, Amr SS. Low grade fibromyxoid

sarcoma: report of a case with fine needle aspiration cytology and

histologic correlation. Acta Cytol 2006;50:208–212.

7. Fetsch JF, Laskin WB, Hallman JR, Lupton GP, Miettinen M.

Neurothekeoma: an analysis of 178 tumors with detailed immuno-

histochemical data and long-term patient follow-up information.

Am J Surg Pathol 2007;31:1103–1114.

8. Fletcher JA, Kozakewich HP, Schoenberg ML, Morton CC.

Cytogenetic findings in pediatric adipose tumors: consistent

rearrangement of chromosome 8 in lipoblastoma. Genes Chromo-

somes Cancer 1993;6:24–29.

9. Hibbard MK, Kozakewich HP, Cin PD, et al. PLAG1 fusion

oncogenes in lipoblastoma. Cancer Res 2000;60:4869–4872.

10. Chen Z, Coffin CM, Scott S, et al. Evidence by spectral karyotyping

that 8q11.2 is nonrandomly involved in lipoblastoma. J Mol Diagn

2000;2:73–77.

11. Bartuma H, Domanski HA, Steyern FVV, Kullendorff CM, Mandahl

N, Mertens F. Cytogenetic and molecular cytogenetic findings in

lipoblastoma. Cancer Genet Cytogenet 2008;183:60–63.

12. Collins MH, Chatten J. Lipoblastoma/lipoblastomatosis: a clinico-

pathologic study of 25 tumors. Am J Surg Pathol 1997;21:1131–

1137.

13. Mentzel T, Calonje E, Fletcher CD. Lipoblastoma and lipoblasto-

matosis: a clinicopathological study of 14 cases. Histopathology

1993;23:527–533.

14. Dilley AV, Patel DL, Hicks MJ, Brandt ML. Lipoblastoma:

pathophysiology and surgical management. J Pediatr Surg 2001;

36:229–231.

15. Mahour GH, Bryan BJ, Isaacs H. Lipoblastoma and lipoblastoma-

tosis—a report of six cases. Surgery 1988;104:577–579.

16. Tabrisky J, Rowe JH, Christine SG, Weinstein ED, Asch M. Benign

mediastinal lipoblastomatosis. J Pediatr Surg 1974;9:399–401.

17. Dudgeon DL, Haller JA. Pediatric lipoblastomatosis: two unusual

cases. Surgery 1984;95:371–373.

18. Sancho-Cerquella V, Gil-Vernet JM, Caceres F, Sanchez-Leon E.

Benign mediastinal lipoblastomatosis. Chir Pediatr 1985;26:379–

381.

19. Marques Gubern A, Jimenez A, Martinez Ibanez V, et al. Embryonal

fatty tumors. Lipoblastoma-lipoblastomatosis. Cir Pediatr 1990;3:

109–112.

20. Whyte AM, Powell N. Mediastinal lipoblastoma of infancy. Clin

Radiol 1990;42:205–206.

21. Federici S, Cuoghi D, Sciutti R. Benign mediastinal lipoblastoma in

a 14-months-old infant. Pediatr Radiol 1992;22:150–151.

22. Ko SF, Shieh CS, Shih TY, et al. Mediastinal lipoblastoma with

intraspinal extension: MRI demonstration. Magn Reson Imaging

1998;16:445–448.

23. Irgau I, McNicholas KW. Mediastinal lipoblastoma involving the

left innominate vein and the left phrenic nerve. J Pediatr Surg 1998;

33:1540–1542.

24. Broeders A, Smet MH, Breysem L, Marchal G. Lipoblastoma: a rare

mediastinal tumour in a child. Pediatr Radiol 2000;30:580.

25. Park CH, Kim KI, Lim YT, Chung SW, Lee CH. Ruptured giant

intrathoracic lipoblastoma in a 4-month-old infant: CT and MR

findings. Pediatr Radiol 2000;30:38–40.

26. Ng CSH, Wan S, Sihoe ADL, et al. Giant mediastinal lipoblastoma.

Asian Cardiovasc Thorac Ann 2001;9:336–338.

27. Ching ASC, Lee SF, Chan YL. Diagnosing paediatric mediastinal

lipoblastoma using ultrasound-guided percutaneous needle biopsy:

review and report. Clin Imaging 2002;26:23–26.

28. Sharma RR, Mahapatra AK, Pawar SJ, Sousa J, Musa MM. An

unusual posterior mediastinal lipoblastoma with spinal epidural

extension presenting as a painful suprascapular swelling: case report

and a brief review of the literature. J Clin Neurosci 2002;9:204–207.

29. Li KT, Wang CR, Lo WC, Hsueh C, Chi WC. Mediastinal

lipoblastoma of infancy: a case report. Chin J Radiol 2003;28:397–

401.

30. Rao K, Eradi B, Marwaha R, Trehan A, Saxena A, Menon P. Images

in paediatrics. Dumbbell tumour of the mediastinum. Arch Dis Child

2003;88:117.

31. Binay T, Shan Z. Giant mediastinal lipoblastoma: a case report with

review of the literature. Indian J Surg 2006;68:108–110.

32. Moholkar S, Sebire NJ, Roebuck DJ. Radiological-pathological

correlation in lipoblastoma and lipoblastomatosis. Pediatr Radiol

2006;36:851–856.

33. Dogan R, Kara M, Firat P, Gedikoglu G. An unusual tumor of the

neck and mediastinum: lipoblastomatosis resulting in paraparesis.

Eur J Cardiothorac Surg 2007;31:325–327.

34. Guillen-Quesada A, Costa-Clara JM. Mediastinal lipoblastoma with

intramedullary extension. Rev Neurol 2007;44:745–746.

35. Kamel HA, Brennan PR, Farrell MA. Cervical epidural lipoblasto-

matosis: changing MR appearance after chemotherapy. Am J

Neuroradiol 1999;20:386–389.

36. Chun YS, Kim WK, Park KW, Lee SC, Jung SE. Lipoblastoma.

J Pediatr Surg 2001;36:905–907.

37. Sciot R, Mandahl N. Lipoblastoma/lipoblastomatosis. In: Fletcher

C, Unni K, Mertens F, eds. Pathology and Genetics Tumors of Soft

Tissue and Bone: Volume 5 of the World Health Organization

Classification of Tumours. Lyon, France: IARC Press, 2002;26–27.

38. Takanami I, Takeuchi K, Naruke M. Low-grade fibromyxoid

sarcoma arising in the mediastinum. J Thorac Cardiovasc Surg

1999;118:970–971.

39. Moran CA, de Christenson MR, Suster S. Thymolipoma: clinico-

pathologic review of 33 cases. Mod Pathol 1995;8:741–744.

40. Gisselsson D, Hoglund M, Mertens F, Cin PD, Mandahl N.

Hibernomas are characterized by homozygous deletions in the

multiple endocrine neoplasia type I region. Metaphase fluorescence

in situ hybridization reveals complex rearrangements not detected

by conventional cytogenetics. Am J Pathol 1999;155:61–66.

MEDIASTINAL LIPOBLASTOMATOSIS 473

41. Morerio C, Panarello C. Soft tissue tumors: lipoblastoma. Atlas

Genet Cytogenet Oncol Haematol. January 2005. Available at http://

atlasgeneticsoncology.org/Tumors/LipoblastomaID5155.html, ac-

cessed October 16, 2009.

42. Billings SD, Giblen G, Fanburg-Smith JC. Superficial low-grade

fibromyxoid sarcoma (Evans tumor): a clinicopathologic analysis of

19 cases with a unique observation in the pediatric population.

Am J Surg Pathol 2005;29:204–210.

43. Mertens F, Fletcher CDM, Antonescu CR, et al. Clinicopathologic

and molecular genetic characterization of low-grade fibromyxoid

sarcoma, and cloning of a novel FUS/CREB3L1 fusion gene. Lab

Investig 2005;85:408–415.

44. Saad AG, Archibald T, Goldsmith JD, Kozakewich H, Debelenko L.

Desmin immunnopositivity differentiates lipoblastoma from other

lipomatous tumors (abstract). Mod Pathol 2007;20(Suppl 2):314a.

45. Kuhnen C, Mentzel T, Fisseler-Eckhoff A, Debiec-Rychter M, Sciot R.

Atypical lipomatous tumor in a 14-year-old patient: distinction from

lipoblastoma using FISH analysis. Virchows Arch 2002;441:299–302.

46. Sciot R, Wever ID, Debiec-Rychter M. Lipoblastoma in a 23-year-

old male: distinction from atypical lipomatous tumor using

cytogenetic and fluorescence in-situ hybridization analysis. Virch-

ows Arch 2003;442:468–471.

47. de Saint Aubain Somerhausen N, Coindre JM, Debiec-Rychter M,

Delplace J, Sciot R. Lipoblastoma in adolescents and young adults:

report of six cases with FISH analysis. Histopathology 2008;52:

294–298.

48. Somers GR, Teshima I, Nasr A, Cook A, Khoury AE, Taylor GP.

Intrascrotal lipoblastoma with a complex karyotype: a case report

and review of the literature. Arch Pathol Lab Med 2004;128:797–

800.

49. Ropke A, Kalinski T, Kluba U, von Falkenhausen U, Wieacker PF,

Ropke M. PLAG1 activation in lipoblastoma coinciding with low-

level amplification of a derivative chromosome 8 with a deletion

del(8)(q13q21.2). Cytogenet Genome Res 2007;119:33–38.

50. Dyck FV, Declercq J, Braem CV, de Ven WJMV. PLAG1, the

prototype of the PLAG gene family: versatility in tumour

development (Review). Int J Oncol 2007;30:765–774.

51. Mognato G, Cecchetto G, Carli M, et al. Is surgical treatment

of lipoblastoma always necessary? J Pediatr Surg 2000;35:1511–

1513.

474 N.K. AMRA AND S.S. AMR