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MOLECULAR AND CLINICAL ONCOLOGY
Abstract. Unicameral bone cyst (UBC) or simple bone
cyst (SBC) is a benign cystic lesion commonly found in
the humerus and femur that is mainly encountered during
childhood. The currently available treatments for UBC of
the hand commonly involve curettage, bone grafting, partial
resection with or without grafting, multiple drilling, fracture
immobilization and observation alone, and steroid injection.
We herein report a case treated with total resection of the cyst
and non‑vascularized bular graft in a 9‑year‑old right‑handed
female patient. The patient presented with a chief complaint
of a large, fast growing lump over the rst metacarpal of the
left hand. Flexion of the rst metacarpophalangeal joint was
limited. After the diagnosis was established with plain radio‑
graphs followed by biopsy, the cyst was completely removed by
resecting the shaft of the metacarpal bone with preservation of
the epiphyseal plate. A bone graft was obtained from the bula
and inserted in the gap, distally attached to the epiphyseal
plate of the metacarpal and xed with a Kirshner wire proxi‑
mally. Radiographs revealed solid union of the bone graft to
the epiphyseal plate at the head after 7 weeks, with improving
function of the thumb. SBC or UBC of the metacarpal bone
is very rare. A more aggressive method, such as in the case
presented herein, may be necessary to treat this condition.
Introduction
Unicameral bone cyst (UBC) or simple bone cyst (SBC) is a
benign cystic lesion commonly found in the humerus and femur
that is mainly encountered during childhood. UBCs typically
remain asymptomatic and represent ~3% of all primary bone
lesions (1). UBC is a serous or serosanguineous uid‑lled
cavity, which is typically inactive and remains asymptomatic
until a pathological fracture occurs. The clinical presentation,
location and radiographic features are rather characteristic
and the diagnosis may be readily established. In 86% of the
cases, UCB occurs within the rst two decades of life and
the proximal humerus is the most common site, whereas it
is rarely observed in the hand. Very few cases of UBC have
been described in the hand to date, including the metacarpals,
phalanges, hamate and lunate bones. Men are twice as likely to
be affected compared with women (2).
The location of UBC may be classified as active
(immediately juxtaposed to the growth plate, not to be
confused with Enneking stage 2 tumors) or inactive (growth
plate not adjacent to the cyst) (3). On clinical examination,
the lesion appears as a well‑dened uid‑lled cyst in the
metaphysis and diaphysis of the affected bone that may
cause pain and swelling. Radiological examination is crucial
for establishing the diagnosis, based on the following
characteristics: Well‑demarcated osteolytic lesion without
marked marginal sclerosis, central location, thinning of the
cortex and intralesional fracture fragment (‘fallen leaf’ or
‘fallen fragment’ sign) (3). The treatment for UBC of the
hand commonly involves curettage, bone grafting, partial
resection with or without grafting, multiple drilling, fracture
immobilization and observation alone, and steroid injection (4).
Case report
A 9‑year‑old right‑handed female patient presented in
February 2017 to the Department of Orthopaedics and
Traumatology of Saiful Anwar Hospital (Malang, Indonesia)
with a chief complaint of a large, fast‑growing lump over
the rst metacarpal of the left hand. The swelling was rst
observed 6 months earlier. The pain was described as dull
and constant, with no diurnal variation. There was no history
of trauma of infection. Physical examination revealed a rm
mass, ~3x4 cm in size, which was tender on palpation, but
with no local rise in temperature (Fig. 1). Flexion of the rst
metacarpophalangeal joint was limited. There was minimal
soft tissue extension and no sensory‑motor decit; the distal
circulation was also normal. On imaging, plain radiographs
of the left hand revealed cystic enlargement of the rst meta‑
carpal that included the base (Fig. 2).
Free non‑vascularized bular graft reconstruction after
resection of metacarpal unicameral bone cyst: A case report
SATRIA PANDU PERSADA ISMA, ISTAN IRMANSYAH IRSAN, I GEDE MADE OKA RAHADITYA,
THOMAS ERWIN C.J. HUWAE and AGUNG RIYANTO BUDI SANTOSO
Department of Orthopaedics and Traumatology, Saiful Anwar Hospital,
Brawijaya University, Malang, Jawa Timur 65112, Indonesia
Received November 8, 2017; Accepted October 30, 2018
DOI: 10.3892/mco.2019.1803
Correspondence to: Dr I Gede Made Oka Rahaditya, Department
of Orthopaedics and Traumatology, Saiful Anwar Hospital, Brawijaya
University, Jalan Jaksa Agung Suprapto No. 2, Klojen, Kota Malang,
Jawa Timur 65112, Indonesia
E‑mail: oka.rahaditya@gmail.com
Key words: unicameral bone cyst, fibular graft, metacarpal cyst
ISMA et al: BONE GRAFT I N UNICAM ERAL M ETACARPAL BONE CYST
2
A biopsy was performed, which revealed that the cyst
was filled with serosanguinous fluid with a haemorrhagic
tinge (Fig. 3). After the diagnosis was established, we decided
to perform total resection of the cyst with placement of a
no n‑vasc ularized bul a r graft. Th e cyst wa s com ple t ely remove d
by resecting the shaft of the metacarpal with preservation of
the epiphyseal plate (Fig. 4). A bone graft was obtained from
the fibula and inserted in the gap, distally attached to the
epiphyseal plate of the metacarpal and xed with Kirshner wire
proximally. A radiograph revealed solid union of the bone graft
to the epiphyseal plate at the head after 7 weeks, with improving
function of the thumb. No recurrence has been reported after the
last follow‑up appointment during January 2018 (Fig. 5).
Discussion
Simple bone cyst or UBC is a serous or serosanguineous
uid‑lled cavity that very rarely develops in the metacarpal
bone. The exact cause is unknown, but epiphyseal plate defect
or venous outow obstruction have been suggested as possible
causes (3). Once diagnosed, UBC poses a dilemma for clinicians,
as its natural history and management remain controversial. The
recurrence rate of UBC ranges from 20 to 50% after various
treatments (5). The differential diagnosis includes aneurysmal
bone cyst and brous dysplasia. When additional examinations
are required, magnetic resonance imaging most accurately
delineates the central uid collection. If a pathological fracture
has occurred, a uid level may be observed, mimicking the
appearance of an aneurysmal bone cyst. There is no convincing
evidence, however, that a UBC may transform to an aneurysmal
bone cyst or other bone lesion (6). The gross pathology of
UBC generally includes a singular uid‑lled cavity, unlike
an aneurysmal bone cyst, which is composed of blood‑lled
cystic cavities that are lined by a thick, eshy membrane with
an endothelial‑like inner layer. In some cases, multilocular
lesions may be present. The bony architecture surrounding the
cyst is non‑reactive and otherwise unremarkable. Microscopic
histological analysis shows a brous tissue membrane, with
oc casional gi ant cell s pre sen t. The u id with i n the cys ts co nta i ns
high levels of prostaglandins and enzymes (7). Traditionally,
plain radiography has been used to diagnose and monitor UBCs,
but advanced imaging has become more popular as technology
has improved. On plain radiography, UBCs appear as lytic,
expansile lesions within the medullary cavity of long bones. The
cortex is thinned, but is not typically compromised structurally.
Rarely, a UBC may develop in the diaphyseal portion of long
bones and is known as a ‘latent’ cyst (8).
Among the various treatment methods mentioned above,
the choice of treatment may vary according to the patient's
age, the bone involved and the location of the cyst within the
bone, and proper treatment should be applied to decrease the
risk of recurrence (4,5). Several agents have been used for
intralesional injection of UBCs; Scaglietti et al rst described
the use of methylprednisolone injections in patients with
UBCs. Recurrence rates of 15‑88% have been reported after
an average of three injections (9).
Figure 1. A 9‑year‑old right‑handed female patient presented with a chief
complaint of a large, fast‑growing lump over t he rst metacarpal of the
left hand. Physical examination revealed a rm mass ~3x4 cm in size, with
limited exion of the rst metacarpophalangeal joint.
Figure 3. Photomicrograph of a biopsy speci men showing bland‑appearing
fibrous tissue and occasional giant cells. H&E, hematoxylin and eosin
staining; magnication, x40 and x100.
Figure 2. Anteroposterior a nd oblique radiograph of the left hand demon‑
strated a cystic enlargement of the rst metacar pal bone that included its base.
MOLECULAR AND CLINICAL ONCOLOGY 3
A more aggressive approach, such as in the present case, is
occasionally necessary to treat UBC. The patient was radically
treated by complete excision and a bular graft. Our rationale
was that, according to Jaffe (1), these cysts are active, as
demonstrated by complete destruction of the metacarpal bone;
furthermore, the patient was aged <10 years and was statisti‑
cally more prone to recurrence (10). This method may also be
used in other bone lesions, such as aneurysmal bone cyst, as
reported by Gundes et al (11), in 2005.
Before proceeding with treatment, a biopsy was performed
to conrm the diagnosis. We decided to perform total resection
of the cyst with preservation of the periosteum and placement
of a non‑vascularized bular graft. The proximal epiphyseal
plate was preserved and xed with a Kirschner wire. After
7 weeks, the function of the thumb was evaluated and union
of the graft was observed. There was no recurrence after
3 months of follow‑up, and the Kirschner wire was removed.
The only known predictor of treatment success is the age of the
patient; patients aged >10 years display higher rates of healing
(90%) compared with younger patients (60%), regardless of the
treatment regimen (8) due to the presence of the active growth
plate in younger patients.
Figure 4. (A) The size of the excised cyst was 2.9x3.1 cm (left) and the length of the graft excised from the bula was ~5.1 cm (right). (B) The graft was inserted
in the gap, distally attached to the epiphyseal plate of the metacarpal bone, then xed proxi mally with Kirshner wi re.
Figure 5. Postoperative X‑ray and clinical picture showing the bular graft xed by Kirshner wire, and improved mobility of the thumb.
ISMA et al: BONE GRAFT I N UNICAM ERAL M ETACARPAL BONE CYST
4
Acknowledgements
Not applicable.
Funding
No funding was received.
Availability of data and materials
Not applicable.
Authors' contributions
IGMOR and TECJH were involved in the drafting of the
manuscript and the revision of the manuscript for important
intellectual content. ARBS and SPPI made substantial contri‑
butions to the design of the case report and were involved in
the surgery. III provided nal approval of the version to be
published. All the authors have read and approved the nal
version of this manuscript.
Ethics approval and consent to participate
Ethics approval was obtained from the local Ethics Committee
of Saiful Anwar Hospital.
Patient consent for publication
The legal guardians of patients included in the present study
provided written, informed consent for the publication of case
details and associated photographs in this manuscript.
Competing interests
The authors declare that they have no competing interests.
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