Chondroid lipoma of the neck: a case report
Katsuyama et al. BMC Res Notes
Chondroid lipoma of the neck: a case report
Yusei Katsuyama 0
Toshiharu Shirai 0
Ryu Terauchi 0
Shinji Tsuchida 0
Naoki Mizoshiri 0
Yuki Mori 0
Toshikazu Kubo 0
0 Department of Orthopedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , 465 Kajii-cho, Kamigyo-ku, Kyoto 602-8566 , Japan
Background: Chondroid lipoma, first described in 1993 by Meis and Enzinger, is a very rare lipomatous tumor. Because it is a benign tumor, it does not require radiotherapy, chemotherapy, or extensive resection. However, histologically, it is often confused with a sarcoma. It is crucial to differentiate chondroid lipoma from sarcoma to avoid choosing an inappropriate treatment strategy. Although MRI, radiography, and ultrasound have been used to evaluate chondroid lipomas, imaging cannot accurately differentiate chondroid lipoma from sarcoma. Case presentation: A 39-year-old man presented to a local clinic with a 1-month history of a painless mass in his left neck. Results of a needle biopsy suggested an atypical lipomatous tumor, and the patient was referred to our hospital. Physical examination revealed a hard and mobile mass in the left neck. Plain X-ray radiographs showed an absence of calcification in the soft tissue mass. MRI revealed a well-defined and lobulated mass, and on T1-weighted images, the lesion showed heterogeneity, with higher signal intensity than that of muscle. On T2-weighted images, the septum had low-signal intensity. On T2-weighted fat-suppressed images, the signal of the mass was completely suppressed. The SUVmax of the mass on FDG PET was 1.84. An additional needle biopsy was performed, and on the basis of the results, we arrived at a diagnosis of well-differentiated liposarcoma. The mass was resected marginally. Macroscopically, the mass was encapsulated and markedly harder than well-differentiated liposarcoma. Histologically, the tumor was composed of myxoid and cartilaginous matrix, and mature fat cells and lipoblast-like cells were present. The final diagnosis was chondroid lipoma, and no recurrence was observed 1 year after surgery. Conclusions: Chondroid lipoma is an extremely rare benign soft tissue tumor that is often confused with sarcoma. It is very important to differentiate chondroid lipoma from sarcoma when the SUVmax value of the mass is low, even when biopsy results suggest that it is a sarcoma.
Chondroid lipoma; Sarcoma; FDG PET
Adipocytic tumor is one of the most common soft
tissue tumors. Chondroid lipoma, first described in 1993
by Meis and Enzinger [
], is a very rare adipocytic tumor.
Histologically, it is often confused with sarcoma,
especially liposarcoma and chondrosarcoma [
it is a benign tumor, and therefore, it does not require
radiotherapy, chemotherapy, or extensive resection [
]. Although some reports have described the
evaluation of chondroid lipoma using MRI, radiography, and
], imaging cannot definitively
differentiate between chondroid lipoma and malignant sarcoma [
]. Moreover, to date, there are no reports of evaluation
using FDG PET. In this report, we present the FDG PET
features of a case of chondroid lipoma.
A healthy 39-year-old Japanese man presented to a
local clinic with a 1-month history of a painless mass
in his left neck. A needle biopsy was performed, and
the results indicated the possibility of an atypical
lipomatous tumor. Subsequently, he was referred to
our hospital. Physical examination revealed a hard
and mobile mass in the left neck, measuring
approximately 10 × 10 cm. Plain X-ray radiographs showed a
soft tissue mass with no calcification in the left neck
(Fig. 1). MR images showed a well-defined and
lobulated mass (Fig. 2a–d). On T1-weighted images, the
mass had heterogeneity, with a higher signal
intensity than that of muscle (Fig. 2a). On T2-weighted
images, the septum had low-signal intensity (Fig. 2b).
On T2-weighted fat-suppressed images, the signal
of the mass was completely suppressed (Fig. 2c). On
gadolinium-enhanced T1-weighted images, the signal
from the mass was enhanced (Fig. 2d). The SUVmax
value of the mass on FDG PET was 1.84, with no
abnormal uptake except in the mass (Fig. 3). An
additional needle biopsy was performed in our hospital,
and evaluation of the results resulted in a
diagnosis of well-differentiated liposarcoma. The mass was
resected marginally because it was considered a
lowgrade tumor. Macroscopically, the mass was
encapsulated and markedly harder than a well-differentiated
liposarcoma (Fig. 4a). The cut surface of the mass was
yellowish and lobulated. Histologically, the tumor was
composed of myxoid and cartilaginous matrix, and
mature fat cells and lipoblast-like cells were present
(Fig. 4b, c). Immunohistochemical analysis showed
that the tumor cells were negative for CDK4, MDM2,
MIB1, and Sox9. On the basis of these findings, we
arrived at a final diagnosis of chondroid lipoma. There
was no recurrence at 1 year after surgery.
Discussion and conclusions
Adipocytic tumor, which is one of the major categories in
the WHO classification of soft tissue tumors of the neck,
has many histologic subtypes [
]. Chondroid lipoma, an
extremely rare benign adipocytic tumor, predominantly
occurs in the proximal extremities and limb girdles [
with a few reported in the head and neck [
patients present with a painless mass.
In previous studies of chondroid lipoma, the
radiographs revealed a soft mass with calcification. The MR
images showed a well-defined and lobulated mass. On
T1-weighted images, the mass had heterogeneity with a
high signal, which is typical of adipose tissue. On
fat-suppressed sequence, the signal was completely suppressed.
On T2-weighted images, the septum had low-signal
]. All these findings are consistent with our
findings in the present case.
Histologically, a chondroid lipoma is a
well-circumscribed and lobulated tumor consisting of mature fat
cells and lipoblast-like cells surrounded by a
myxoidchondroid matrix [
]. It is histologically similar to
liposarcoma, chondrosarcoma, myxoid liposarcoma, and
Treatment of malignant tumors entails radiotherapy,
chemotherapy, and extensive resection; however, benign
tumors require only marginal resection [
it is very important to differentiate benign tumors from
malignant tumors, including the differentiation of benign
lipomatous tumors such as chondroid lipoma from
malignant tumors, in order to avoid unnecessary
treatment and the associated adverse effects.
Several reports have demonstrated the usefulness of
diffusion-weighted MRI in the evaluation of soft tissue
tumors. Razek et al. [
] showed that the apparent
diffusion coefficient value of benign soft tissue tumors was
significantly higher than that of malignant tumors. In
contrast, another study showed that there was no
significant difference in ADC values between benign and
malignant tumors [
]. Surov et al. [
] reported that
diffusion is determined by the balance between matrix and
cellularity, but not the dignity of the lesion. Evaluation
with diffusion-weighted MRI may be useful for
differentiating chondroid lipoma from sarcoma.
To date, there have been no reports on the evaluation of
chondroid liposarcoma by FDG PET. In the present case,
FDG PET was performed to evaluate the malignancy of
the tumor, and the SUVmax value of the mass was 1.84.
Liposarcoma patients with SUVmax > 3.6 have a
significantly worse prognosis [
]. Although not all lesions with
low SUVmax value are benign, a low SUVmax value
generally indicates a benign or low-grade tumor.
In addition, our findings suggest that even when a mass
is diagnosed as sarcoma according to biopsy results, it is
important to include chondroid lipoma in the differential
diagnosis when the mass is very hard, well-defined, and
lobulated, and when the SUVmax value of the mass is low.
In conclusion, we report a very rare case of chondroid
lipoma of the neck presenting as a hard mass and
diagnosed on the basis of FDG PET findings. In order to
avoid overtreatment due to incorrect diagnosis, it is very
important to differentiate chondroid lipoma from
sarcoma when the SUVmax value of the mass is low, even
when the mass is suspected to be a sarcoma on the basis
of biopsy results.
CT: computed tomography; MRI: magnetic resonance image; FDG PET:
fluorodeoxyglucose-positron emission tomography; SUV: standardized uptake
YK designed the study, and wrote the initial draft of the manuscript. TS
assisted in the preparation of the manuscript. RT, ST, NM, YM and TK have
contributed to references collection and interpretation, and critically
reviewed the manuscript. All authors agree to be accountable for all
aspects of the work in ensuring that questions related to the accuracy
or integrity of any part of the work are appropriately investigated and
resolved. All authors read and approved the final manuscript
The authors declare that they have no competing interests.
Availability of data and materials
Consent to publish
Written informed consent was obtained from the patient for publication of
this case report and accompanying images.
Ethics approval and consent to participate
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