ANTICANCER RESEARCH 27: 4311-4314 (2007)
Successful Treatment of Bilateral Calcaneal Intraosseous
Lipomas Using Endoscopically Assisted Tumor Resection
HIROYUKI FUTANI, SATORU FUKUNAGA, SHOJI NISHIO, MASAYOSHI YAGI and SHINICHI YOSHIYA
Department of Orthopaedic Surgery, Hyogo College of Medicine, Hyogo 663-8501, Japan
Abstract. Background: Intraosseous lipoma is a rare benign
bone tumor. Removal is required when there is pain or the
lesion is large enough to lead to a pathological fracture.
However, conventional surgery requires non-weight-bearing for
at least 6 weeks. Here, we present a case with bilateral
calcaneal intraosseous lipomas successfully treated by the use
of endoscopically assisted curettage. Case Presentation: A 30year-old female noted pain in both heels for 1 year.
Radiological findings revealed well-defined lytic lesions at the
neck of both calcanei. Magnetic resonance (MR) images
showed hyper-intense signals on the T1 and T2 sequences.
Curettage was performed through small bone fenestrations in
the medial and lateral aspects under observation with a 2.7mm-diameter Hopkins telescope. The bone void was filled with
beta-tricalcium phosphate (‚-TCP). Full weight-bearing was
permitted the day after the surgery. Conclusion: Endoscopically
assisted curettage is feasible in patients with benign bone
tumors of the calcanei to avoid a long period of non-weightbearing post-operatively.
Intraosseous lipoma is a rare benign bone tumor (1-3). The
calcaneus is the second most common location after the
proximal femur (2). This condition is frequently
asymptomatic (1-4). However, surgery is required when the
tumor causes pain or a lesion is large enough to lead to a
pathological fracture (2, 4-7). Curettage followed by bone
graft is the most common surgery (2, 4, 6). However, the
conventional open procedure is associated with slow
functional recovery and cosmetic disadvantage due to a
large operative incision. Previous studies have reported that
a period of non-weight-bearing varying from 6 to 12 months
is needed after curettage and bone graft by the open
procedure (5, 8-10). Recently, endoscopically assisted tumor
Correspondence to: Dr. Hiroyuki Futani, Department of
Orthopaedic Surgery, Hyogo College of Medicine, 1-1 Mukogawa
Nishinomiya, Hyogo 663-8501, Japan. Tel: +81 798 45 6452, Fax:
+81 798 45 6453, e-mail: [email protected]
Key Words: Intraosseous lipoma, endoscopic tumor resection.
0250-7005/2007 $2.00+.40
resection has been introduced as a feasible technique to
obtain early functional recovery (11, 12).
We present a patient with bilateral calcaneal intraosseous
lipomas. Both tumors were successfully removed at the
same time by the use of endoscopically assisted tumor
curettage through a small bony hole, followed by filling of
the bone void with beta-tricalcium phosphate (‚-TCP)
(OSferion Olympus, Tokyo, Japan). Written consent was
obtained from the patient for publication of this study.
Case Presentation
A 30-year-old female noted right heel pain after she hit her
heel in the bath tub. Soon after she also experienced left
heel pain without any trauma. In her daily activity the pain
did not bother her. However, her pain worsened with
sporting activity, especially while playing badminton once a
week. The pain was relieved overnight with rest. One year
later she was referred to the bone and soft tumor section of
our Department.
On physical examination, the lateral aspects of each central
calcaneus were tender. A lateral X-ray revealed a well-defined
lytic lesion at the base of the neck of the right calcaneus
(Ward’s triangle) (Figure 1). Computerized tomography (CT)
demonstrated the lesion as a well-circumscribed area of
lucency with an expanded and thin sclerotic rim in the right
calcaneus. A well-circumscribed area of lucency was also
found in the left calcaneus (Figure 2). The size of the right
tumor was 3.5x2x2 cm and that of the left tumor was 2x2x1.5
cm. On magnetic resonance (MR) imaging the lesions had
hyper-intense signals on the T1 and T2 sequences, suggesting
fatty tissues (Figure 3). No enhancement was observed by
Gadolinium enhanced T1 weighted MR imaging. The lesions
virtually disappeared on the fat-suppressed T2 weighted MR
images, confirming fatty tissues. Thus, most likely the
diagnosis would be intraosseous lipomas.
Surgery was performed under spinal anesthesia with the
patient in the supine position. A pneumatic tourniquet was
used. A 1 cm skin incision was made over both the medial and
the lateral aspects of the right calcaneous and 0.5x0.5 cm bone
fenestrations were made on each side as portals. A 2.7 mm
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ANTICANCER RESEARCH 27: 4311-4314 (2007)
Figure 2. A CT image shows radiolucency in both calcanei. The right
tumor is bigger than the left one. Especially, the cortical wall of the right
calcaneus was bulged by the tumor expansion.
Figure 1. A lateral X-ray shows a well-defined lytic lesion at the base of
the neck of the right calcaneus.
diameter, 30 degrees Hopkins telescope (Karl Storz, Tuttlingen,
Germany) was introduced through both the medial and the
lateral portals. A yellowish tumor was observed through the
endoscope (Figure 4a). Under careful observation of one
portal, the tumor was removed by punch and sharp curette
inserted through the other portal (Figure 4 b, c).
Intraoperatively, an imaging intensifier was also used to confirm
that those tools reached the entire bone cavity. After the tumor
resection, the bone void was filled with beta-tricalcium
phosphate (‚-TCP) (OSferion Olympus, Tokyo, Japan) -TCP
(Figure 5). The gross appearance of the resected specimen
consisted of fibro-osseous fragments with small pieces of yellow
soft tissue. The same procedure was repeated on the left side.
Histology revealed that the lesion was composed of mature fat
cells surrounding a few residual bone trabeculae (Figure 6).
Full weightbearing was permitted the day after surgery.
Over a 3 month period, the ‚-TCP was resolved and
replaced by mature new bone. No recurrence was found 2
years after surgery.
Discussion
Intraosseous lipomas account for approximately 0.1% of all
primary bone tumors. However, this may not be the true
incidence since the lesions are frequently asymptomatic (1,
3). The largest number in the literature presented by
4312
Figure 3. A T1 weighted MR image delineates high intensity areas,
indicating fatty tissues of both tumors in calcanei.
Milagram (2) was of 61 patients with intraosseous lipomas, of
which 21 were located in the proximal femur (34%) and five
each (8 %) in the calcaneus and the ilium followed by 4 each
(7%) in the proximal tibia, rib and mid-humerus. Bilaterally
calcaneal involvement of intraosseous lipomas has been
reported in only four cases in the English literature (2, 1315). Due to a painful lesion one patient underwent curettage
followed by filling of the bone void with calcium sulfate (13).
In the case reported by Milgram (2; Case #61) the patient
Futani et al: Endoscopically Assisted Resection of Calcaneal Intraosseous Lipomas
Figure 5. Immediate postoperative roentogenogram showing a dense
region of the ‚-TCP after the removal of bone tumor in the right
calcaneous.
Figure 6. Histology of the tumor, comprised of viable fat and small bone
trabculae, indicating a lipoma (bar equals 100 Ìm).
Figure 4. Endoscopic images from inside the calcaneus show: a) a yellow
tumor; b) the tumor is removed by use of a grasper; c) the bone void and
cortical wall after removal of the tumor.
underwent curettage, however, detailed information of the
surgery was not mentioned. The other 2 cases did not have
surgery since the lesions were asymptomatic.
The postoperative course may vary, depending upon the
size, location, and extent of the lesion as well as involvement
of the subtalar joint (5). Goldenhar et al. (10) reported a
conventional procedure of curettage followed by bone graft
using a 2x2 cm bone fenestration in the central lateral
calcaneus. This procedure required non-weight-bearing for
12 weeks to avoid pathological fracture postoperatively.
With the same procedure, others have reported a period of
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ANTICANCER RESEARCH 27: 4311-4314 (2007)
non-weight-bearing of 6 to 10 weeks (5, 8, 9) even though a
mixture of hydroxyapatite and bone graft was used to
reinforce the residual bone. Endoscopically assisted tumor
curettage has an advantage in this regard by avoiding the
risk of postoperative pathological fracture since the small
bony fenestration (0.5x0.5 cm) can preserve the stiffness and
strength of the affected bone. In terms of early mobilization,
this technique can reduce the time to full weight-bearing. In
fact, our patient could walk with full weight-bearing the day
after the surgery.
Historically, extra-articular endoscopic resection of bone
tumors was first introduced in 1995 and applied in the case
of a chondroblastoma of the femoral head (11, 12). When
the tumor is located in a bone, the endoscope can decrease
the blind area of the lesion. Consequently, complete
curettage is assured even though the portals are small. So
far, endoscopic curettage without bone graft has been
reported in only one case of a secondary calcaneal
aneurysmal bone cyst with chondroblastoma (16).
Several graft options, after the curettage of this condition,
have been reported, such as autologous bone graft (2),
autologous bone graft with hydroxyapatite (7), calcium
sulfate (13), or curettage without graft (17). The advantage
of using a bone substitute is to avoid the pain of a donor
site. Among bone substitute materials, Ogose et al. (18)
have shown the advantage of ‚-TCP compared to
hydoxyapatite due to the nature of the remodeling and
superior osteoconductivity. In addition, Chazono et al. (19)
determined that filling a bone defect with ‚-TCP was
superior to leaving a bone defect without a graft, in terms
of new bone formation. The present case is the first report
of the application of ‚-TCP to a calcaneal intraosseous
lipoma. ‚-TCP was gradually replaced by newly formed
bone without any complication by 3 months after surgery.
Endoscopically assisted tumor curettage followed by filling
the bone defect with ‚-TCP is feasible for patients with
calcaneal intraosseous lipoma to avoid a long-term period of
non-weight bearing and to obtain early functional recovery.
Acknowledgements
In support of preparation of this manuscript one of the authors
(H.F.) received a grant from the Fund of the Ministry of
Education, Science, Sports, and Culture, Japan.
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Received May 25, 2007
Revised August 2, 2007
Accepted August 14, 2007