authors: salman t. al-malki, abdullah s. al-khamiss

Manuscript Accepted Peer Reviewed | Early View Article

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Early View Article: Online published version of an accepted article before publication in the

final form.

Journal Name: Journal of Case Reports and Images in Pathology

Type of Article: Case Report

Title: Chondroid Lipoma: A Rare Recently Described Benign Lipomatous Tumor (Case

Report)

Authors: Salman T. Al-Malki, Abdullah S. Al-Khamiss

doi: To be assigned

Early view version published: July 14 , 2015

How to cite the article: Al-Malki S.T, Al-Khamiss A.S. Chondroid Lipoma: A Rare Recently

Described Benign Lipomatous Tumor (Case Report). Journal of Case Reports and Images

in Pathology, Forthcoming 2015.

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TYPE OF ARTICLE: Case Report 1

2

TITLE: Chondroid Lipoma: A Rare Recently Described Benign Lipomatous Tumor 3

(Case Report) 4

5

AUTHORS: 6

Salman T. Al-Malki1, MD , Abdullah S. Al-Khamiss2, MD 7

8

AFFILIATIONS: 9

1Department of Pathology, King Fahad Medical City, Riyadh, Saudi Arabia 10

2Department of Pathology, King Fahad Medical City, Riyadh, Saudi Arabia 11

12

CORRESPONDING AUTHOR DETAILS 13

Abdullah Saleh Al-Khamiss, Department of Pathology, King Fahad Medical City, Al-14

Olaya, Khurais road, Riyadh city, Riyadh region, Kingdom of Saudi Arabia. 15

Phone: 00966-506-13-9201 16

E-mail: [email protected] 17

18

Guarantor of Submission : The corresponding author is the guarantor of 19

submission. 20


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(Case Report) 22

23

ABSTRACT 24

25

INTRODUCTION 26

lipomatous tumors group is a group of tumors containing both benign and malignant 27

neoplasm, that sometimes have some morphological overlapping. Chondroid lipoma 28

is one of the rare benign lipomatous tumors that have been described recently. 29

Although it is benign in nature, its microscopic picture is mimicking some of the 30

malignant tumors, especially myxoid liposarcoma. CASE REPORT: A 51-year-old 31

lady presented with a mass arising in her right thigh. This mass grew slowly during 32

the several months ago. Radiologically, it was described as a well-circumscribed 33

benign mass with scanty fatty component. Surgical excision and primary closure was 34

performed for the patient. Histopathologic examination demonstrated a well-35

circumscribed mass formed by cords and nests of lipoblasts and lipocytes embedded 36

in a prominent myxoid to hyalinized chondroid matrix. A panel of 37

immunohistochemical (IHC) stains had been done. From the clinical, radiological, 38

and pathological information, the diagnosis of chondroid lipoma was made. 39

CONCLUSION: This case is considered a rare variant of lipoma and easily can be 40

misdiagnosed as myxoid liposarcoma or extra-skeletal myxoid chondrosarcoma. So, 41

the pathologist should be aware of this entity when he/she comes across such 42

cases. 43

44

Keywords: Lipoma, Chondroid lipoma, Myxoid liposarcoma, Extra-skeletal 45

chondrosarcoma. 46


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(Case Report) 48

49

INTRODUCTION 50

Lipomatous tumors have a broad clinical and morphological spectrum ranging from 51

benign cases to malignant ones. Myxoid liposarcoma is the second most common 52

type of liposarcoma. It represents 30% of liposarcomatous tumors in general. Mostly, 53

it arising in the thigh of 30-40 years age group patients in both sex equally. It has the 54

tendency to recur and metastasis distally. In the last few years, a rare variant of 55

benign lipomatous tumors have been described, called "chondroid lipoma". Although 56

this variant is benign in nature, it histopathological morphology make it one of the 57

great mimicker of many malignant soft tissue tumors, especially myxoid liposarcoma. 58

59

CASE REPORT 60

51-years-old female patient is presenting to the OPD with a right thigh swelling. This 61

swelling starts to appear several months ago. It is painless but slowly progressive. 62

There is no decrease in weight or loss of appetite. 63

On physical examination, there is a non-tender mass in the upper part of the right 64

thigh. This mass is firm, deeply-seated, roughly oval, and not pulsated or fixed to the 65

skin. CBC, LFT, RFT, and minerals (Na+, K+, & Ca+2) are all within normal limits. 66

The radiological examination shows well-defined mass contain only a small amount 67

of fatty tissue distributed centrally & peripherally (Figure 1). The mass have been 68

excised and the gross picture shows a circumscribed lobulated tan-yellowish mass 69

measuring 5.2 x 4.3 x 3.8 cm (Figure 2). 70

Microscopically, the mass is well-circumscribed and formed by lobules separated by 71

fibrous septa. Each lobule is formed by nests and cords of cells embedded in a 72

chondroid-myxoid background (Figure 3). The cells have variable morphology: some 73

of them are mature adipocytes with single large intracytoplasmic vacuole, others 74

have multi-vacuolated cytoplasm resembling lipoblasts (Figure 4 and 5). 75


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Some of the cells have a pericytoplasmic clear zone (lacunae-like), making it 76

resembling chondrocytes (Figure 5). Mild nuclear pleomorphism and rare scattered 77

mitoses are noted (Figure 6). No chicken-wire blood vessels seen in the background. 78

IHC stains shows that the tumor cells are positive for vimentin (Figure 7) & S100 79

(Figure 8) and negative for CK, EMA, CD34, SMA, desmin, & HMB45. 80

Based on the previous findings, a diagnosis of chondroid lipoma is made. The 81

patient had been discharged with a follow-up appointment. 82

83

DISCUSSION 84

Lipomatous tumors are one of the most common soft tissue tumors that usually 85

diagnosed by the pathologists. They have a wide range of morphological and 86

behavioral spectrum from benign things (lipoma) to malignant one (liposarcoma) [1-87

2]. Chondroid lipoma is a very rare variant of lipomatous tumors [1,3]. It had been 88

firstly described by Meis and Enzinger in 1993 [4]. They describe it as a lipoma 89

contains two histological components: a) adipose tissue (containing mature fat cells 90

& lipoblasts), and b) cartilaginous tissue (containing chondroblasts & hyaline matrix) 91

[4]. Now, according to the World Health Organization (WHO) 2002, chondroid lipoma 92

is defined as “a unique & recently recognized benign adipose tissue tumor containing 93

lipoblasts, mature fat cells, and chondroid matrix" [3]. Why this tumor occurs? still 94

unknown, but there are two hypothesis regarding to the origin of the cartilaginous 95

component of this tumor: a) it represents a metaplastic changes in an ordinary 96

lipoma due to a mechanical stress, and b) it arising from the multipotential stem cells 97

under the influence of some growth factors that are present in this lesion [3,5]. 98

Regarding to the age group, usually this type of tumor will affect adult people in their 99

third and fourth decades [3,6] but it can arise in pediatric age group also [7]. It arise 100

more in females [3,6]. Proximal extremities and limb girdles are the most common 101

affected sites, however, trunk and head & neck areas can be affected too [3]. It 102


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presented as a painless, slowly growing, superficial or deeply seated soft tissue 103

mass [3,6]. 104

Grossly, it is a well-circumscribed lobulated tan-yellow mass with a size range of 2-7 105

cm [3,6]. Microscopically, the tumor is a well-circumscribed lobulated mass with 106

lobules separated by fibrous septa [3,6]. Its histological hallmarks are nests and 107

cords of abundant uni- and multi-vacuolated lipoblasts embedded in a prominent 108

myxoid to hyalinized chondroid matrix admixed with a variable amount of mature 109

adipose tissue [3]. Lipocytes are also present [3,6]. NO/mild pleomorphism and rare 110

mitosis are accepted [3,6]. Some small cells with lacunae-like zone are present [3,6]. 111

No chicken-wire blood vessels in the background but some scattered thick wall blood 112

vessels are noticed [3,6]. The cells contain both glycogen and lipid which highlighted 113

by PAS and oil-red O stains, respectively [1,3,6]. Reticulin stain shows that there is a 114

pericellular reticulin fibers [1-3,6]. Immunohistochemically, the cells are positive for 115

S100, vimentin, CD68, and rarely for CK [1,3,6]. They are negative for EMA, HMB45, 116

SMA, MSA, GFAP, and CD57 [1,3,6]. Ki67 proliferation index is less than 1% [3]. 117

Cytogenetically, some of chondroid lipomas have t(11;16) which resulting in C11 or 118

f95-MKL2 fusion oncogene [2-3,6]. How this fusion will lead to the formation of this 119

tumor? Still no clear answer. 120

The differential diagnosis of chondroid lipoma includes benign and malignant tumors 121

[1-3,6,8-9]. Myxoid liposarcoma is one of the most mimickers for chondroid lipoma 122

but it can be differentiated by its infiltrative pattern, the presence of chicken-wire 123

blood vessels, and the presence of t(12;16) or t(12;22) which will lead to the fusion of 124

DDIT3 with FUS or EWS1 genes, respectively [2-3,6]. Myxoid chondrosarcoma is 125

another mimickers for chondroid lipoma but it can be differentiated by its infiltrative 126

pattern, absence of the cytoplasmic vacuoles, absence of the fatty components, and 127

the presence of chromosomal translocation that causing fusion of NR4A3 in 128

chromosome-9 [2-3,6]. Spindle cell lipoma is one of the differential diagnosis of 129

chondroid lipoma but it have ropey collagen fibers, lack of chondroid background, 130

has diffusely expressed CD34 in 131


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the spindle cell component, and a deletion involving chromosomes 13q and 16q [2-132

3,6]. 133

It is important to know this type of benign tumor to avoid misdiagnosing it as a 134

sarcoma and the subsequent overtreatment of the patients with radical surgery, 135

chemotherapy, and radiotherapy [1-4,6,8,10-11]. Chondroid lipoma will be cured with 136

simple excision [3]. It will not recur or metastasis [3]. 137

138

CONCLUSION 139

Chondroid lipoma is a rare variant of lipoma with histomorphological features that 140

mimic myxoid liposarcoma and extra-skeletal myxoid chondrosarcoma. Attention 141

should be paid from the pathologist when he/she evaluates such cases, particularly 142

on core biopsy sample. 143

144

CONFLICT OF INTEREST 145

The authors declare that there is no conflict of interests regarding the publication of 146

this article. 147

148

AUTHOR’S CONTRIBUTIONS 149

Salman T. Al-Malki - Conception and design, Acquisition of data, Analysis and 150

interpretation of data, Drafting the article, Critical revision of the article, Final 151

approval of the version to be published. 152

Abdullah S. Al-Khamiss - Conception and design, Acquisition of data, Analysis and 153

interpretation of data, Drafting the article, Critical revision of the article, Final 154

approval of the version to be published. 155

156

ACKNOWLEDGEMENTS 157

Nothing 158

159

REFERENCES 160

1. Gokhale U, Pillai GR, Varghese PV, Samarsinghe D. Chondroid lipoma: a 161

case report. Oman Medical Journal 2008; Volume 23, Issue 2, April 2008. 162


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2. De Vreeze R, Van Coevorden F, Boerrigter L, Nederlof PM, Haas RL, Bras J, 163

et al. Research article delineation of chondroid lipoma: an 164

immunohistochemical and molecular biological analysis. Hindawi Publishing 165

Corporation Sarcoma 2011; Volume 2011, Article ID 638403: 5 pages. 166

3. Fletcher C.D.M., Unni K.K., Mertens F. (Eds.): World Health Organization 167

(WHO) Classification of Tumours. Pathology and Genetics of Tumours of Soft 168

Tissue and Bone. IARC Press: Lyon 2002. 169

4. Meis JM, Enzinger FM. Chondroid lipoma. A unique tumor simulating 170

liposarcoma and myxoid chondrosarcoma. Am J SurgPathol 1993 171

Nov;17(11):1103-1112. 172

5. Hwang HS, Lee WJ, Lim HK, Chun HK, Ahn GH. Chondrolipoma in the pelvic 173

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review. Annals of Diagnostic Pathology 2012;16:230-234. 176

7. Kindblom LG. Lipomatous tumors-how we have reached our present views, 177

what controversies remain and why we still face diagnostic problems: a tribute 178

to Dr Franz Enzinger. AdvAnatPathol 2006 Nov;13(6):279-285. 179

8. Gomez-Ortega JM, Rodilla IG, De Lerma JM. Chondroid lipoma a newly 180

described lesion that may be mistaken for malignancy. Oral Surgery, Oral 181

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9. Lakshmiah SR, Scott KW, Whear NM, Monoghan A. Chondroid lipoma: a rare 184

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Maxillofacial Surgery 2000 December; Volume 29, Issue 6:445-446. 186

10. Nielsen GP, O’Connell JX, Dickersin GR, Rosenberg AE.Chondroid lipoma, a 187

tumor of white fat cells.A brief report of two cases with ultrastructural analysis. 188

Am J SurgPathol 1995 Nov;19(11):1272-1276. 189

11. Mentzel T, Remmler K, Katenkamp D. Chondroid lipoma. Clinicopathological, 190

immunohistochemical, and ultrastructural analysis of six cases of a distinct 191

entity in the spectrum of lipomas.Pathologe 1999 Nov;20(6):330-334. 192

193


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FIGURE LEGENDS 194

Figure 1: Radiological picture showing thigh with deep-seated well-circumscribed 195

mass. 196

Figure 2: Gross picture showing a circumscribed tan-yellow lobulated mass. 197

Figure 3: Low-power view demonstrates that the lesion has lobular pattern with a 198

myxoid background (H&E x40). 199

Figure 4: Intermediate-power view shows mature fat cells with degenerative changes 200

and the surrounding chondromyxoid matrix (H&E x200). 201

Figure 5: High-power view showing mature fat cells and lipoblasts embedded in a 202

chondroid matrix. Some lacunae-like cells are also present (H&E x400). 203

Figure 6: High-power view showing many lipoblasts with mild nuclear pleomorphism 204

embedded in a chondroid matrix (H&E x400). 205

Figure 7: The cells are diffusely positive for vimentin (immunohistochemistry stain 206

x200). 207

Figure 8: The cells are focally positive for S100 (immunohistochemistry stain x200). 208

FIGURE 209

210

211

Figure 1: Radiological picture showing thigh with deep-seated well-circumscribed 212

mass. 213

214


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215

Figure 2: Gross picture showing a circumscribed tan-yellow lobulated mass. 216

217

218

Figure 3: Low-power view demonstrates that the lesion has lobular pattern with a 219

myxoid background (H&E x40). 220

221


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222

Figure 4: Intermediat-power view shows mature fat cells with degenerative changes 223

and the surrounding chondromyxoid matrix. (H&E x200). 224

225

226

Figure 5: High-power veiow showing mature fat cells and lipoblasts embedded in a 227

chondroid matrix. Some lacunae-like cells are also present (H&E x400). 228

229

230

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232

233

Figure 6: High-power veiow showing many lipoblasts with mild nuclear pleomorphism 234

embedded in a chondroid matrix .(H&E x400). 235

236

237

238

239

Figure 7: The cells are diffusely positive for vimentin (immunohistochemistry stain 240

x200). 241

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244

Figure 8: The cells are focally positive for S100 (immunohistochemistry stain x200). 245

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authors: salman t. al-malki, abdullah s. al-khamiss

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