Chondromyxoid Fibroma of The Distal Clavicle: Report of An Additional Case at Very Unusual Anatomic Location
Jean Marie Vianney Hope*1, Jean Claude Sane2, Souleymane Diao1, Francis Mugabo3, Jean Paul Bitega4, Anselme Noaga Nikiema1, Amadou Ndiassé Kassé1, El Hadji Souleymane Camara1, Mouhamadou Habib Sy1
1Orthopedics and Trauma Surgery, Department of Grand-Yoff General Hospital, Cheikh Anta Diop University of Dakar, Senegal
2Gaston Berger University of Saint Louis, Senegal
3Rwanda Military Hospital, University of Rwanda, East Africa
4PLA National Defence University, Beijing, China
Submission: September 26, 2018; Published: October 09, 2018
*Corresponding author: Jean Marie Vianney Hope, Orthopedic Surgeon Orthopedics and Trauma Surgery Department Grand-Yoff General Hospital, Dakar, Senegal, Tel: +221705899741; Email: firstname.lastname@example.org
How to cite this article: Hope J M V, Sane JC, Souleymane D, Mugabo F, Bitega JP, Nikiema AN, Kassé AN, El Hadji S C, Sy M H. Chondromyxoid
Fibroma of The Distal Clavicle: Report of An Additional Case at Very Unusual Anatomic Location. JOJ Orthoped Ortho Surg. 2018; 2(2): 555581. DOI: 10.19080/JOJOOS.2018.02.555581
Chondromyxoid fibroma is a relatively rare, benign cartilaginous bone tumor accounting for <1% of primary bone neoplasms, usually involving bones of the lower extremity during the second or third decades of life. We report one such case occurring in one-third distal end of the right clavicle of a 7-year-old schoolgirl. After the definitive diagnosis made by histological examination, the patient underwent curettage, followed by phenolization and synthetic processed bone grafting. The patient made an uneventful post-operative recovery. She has been followed up for 5 years to date, with no evidence of recurrence.
Chondromyxoid fibroma (CMF) is a rare benign cartilaginous tumor accounting for <1% of primary bone neoplasms [1-4]. It was first described as a distinctive clinical entity by Jaffe and Lichtenstein in 1948; formerly it was classified as myxoma or a myxomatous variant of giant-cell tumour, or mistaken for a malignant lesion, especially chondrosarcoma, chondromyxosarcoma or myxosarcoma . The 2002 World Health Organization (WHO) classification of bone and soft tissue tumors  defines CMF as ‘‘benign tumor characterized by lobules of spindle or stellate shaped cells with abundant myxoid or chondroid intercellular material’’. It usually presents during the second or third decades of life [7-10]. Most CMF cases occur in the bones of the lower extremities and has a tendency for the metaphyseal region of the distal femur and proximal tibia, followed by the foot [11-13]. Other frequent sites are the pelvis, spine and sternum [14,15]. In general, the clavicle is a rare site for primary bone tumors, approximately 80% of which are malignant . CMF of the clavicle is extremely rare. To our knowledge, only seven cases have been previously mentioned in the English language literature [13,16-21]. We report the clinical presentation, imaging and pathological findings of an additional patient with CMF arising from one-third distal end of the right clavicle.
The parents of a 7-year-old schoolgirl noticed swelling over one-third distal end of the right clavicle that had slowly increased in size over 5 months. The swelling was associated with a constant slight dull pain. Her parents initially attributed this pain to carrying of a school bag that was often slung over her right shoulder. She was previously healthy without trauma history of the shoulder. She was then brought to the hospital outpatient department (OPD) for evaluation of her condition.
On physical examination, a slightly tender, fixed, bony, hard mass measuring 2.9 cm x 1.3 cm was palpable over the acromioclavicular joint of the right shoulder. The overlying skin was normal. The range of motion of shoulder was slightly restricted due to pain. No other abnormalities were revealed by the full systemic review. All laboratory tests (including full blood count, electrolytes, erythrocyte sedimentation rate, C-reactive protein) were within normal limits.
Conventional radiographs (Figure 1) showed an expanded radiolucent osteolytic lesion at the distal end of right clavicle. The lesion had well defined margins with internal septa. No periosteal reaction or associated soft tissue mass was present. Reconstructed coronal Computed Tomography (CT) image (Figure 2) showed that the lesion had a thin sclerotic rim and endosteal
scalloping measuring 2.9 cm x 1.3 cm. The margins of the lesion
were preserved without erosion. The acromioclavicular joint was
not involved. No calcification or associated soft tissue mass were
Open biopsy was then carried out. On inspection during the
operation, the cortex surrounding the tumor was thinned and
expanded, rendering a diagnosis of a chondroid lesion without
overt malignancy but deferring the final decision to paraffin
histology. The histological sections showed mitochondrion lobules
with increased cellularity in the peripheral area. The tumors
were characterized by components of chondroid, myxoid and
fibrous tissues in various proportions. Multiple stellate cells with
compact nuclei were seen within the chondromyxoid components.
Giant cells and osteoid formation were also observed. Secondary
changes, such as necrosis or hemorrhage, were not seen. The
histological diagnosis was chondromyxoid fibroma (Figure 3).
The tumor was curetted until it was completely removed
and treated with phenol to reduce possible recurrence. The
cavity was then packed with synthetic processed bone graft. The
patient made an uneventful post-operative recovery. She has been
followed up for 5 years to date, with no evidence of recurrence
Chondromyxoid fibroma is a rare tumor which comprises less
than 1% of all benign bone tumors, and it is the least common
benign cartilaginous tumor of bone . More than 700 cases
of CMF have been previously mentioned in the modern English
language literature, and only seven cases involved the clavicle
[13,16-21]. This tumour occurs with an approximately equal
sex ratio [10-16]. The patient age is variable, ranging from 6 to
87 years. However, most occur in the second or third decade
of life with mean age of 31.1 years, with a second peak in the
fifth to seventh decades [8-10,17,21,23]. A case of congenital
chondromyxoid fibroma has been reported by Mendoza et al.
 Our case is a 7-year-old female patient. The age is below the
common peak incidence of CMF because of early diagnosis. The
symptoms presented were pain and swelling over the affected
area. It measured 2.9 cm x 1.3 cm in size at clinical presentation.
This is in agreement with other investigators . There may also
be some restriction of movement, as was seen in our case.
The clavicle is classified as a flat bone. It has a unique
development process, with almost the entire clavicle developing by intramembranous ossification. However, the sternal and
acromial ends are performed in cartilage, known as endochondral
ossification. Chondromyxoid fibroma arises from cells related to
the epiphyseal cartilage . Therefore, the location of tumors in
our case may be explained by the endochondral ossification at the
acromial (or distal) end.
Because they frequently have atypical pleomorphic hyperchromatic
nuclei, without radiographic and clinical correlation,
chondromyxoid fibroma may potentially be misinterpreted as a
malignant lesion; however, mitoses are a rarity [5-7,9,10,13]. The
differential diagnosis of CMF includes myxoid chondrosarcoma,
CMF-like or chondroblastic osteosarcomas, fibrous dysplasia, and
chondroblastomas . Histologically, the three components characterizing
CMF are chondroid, the myxoid and the fibrous tissue in
varying proportions . In our case, the well-preserved fat plane
and the lack of features of an aggressive bone lesion, such as soft
tissue mass or periosteal reaction, led us to an initial diagnosis of
a benign rather than malignant bone tumor. Our final diagnosis
depended on histological examination of the biopsy material.
CMF can be treated with curettage alone or together with
bone grafting or polymethylmethacrylate. The overall rate of
recurrence of chondromyxoid fibroma following curettage has
been reported to be around 25%, although bone grafting or bone
cement can reduce it . The age of diagnosis was proposed
as a factor for increased recurrence rates, with the suggestion
that the reduced resistance of the pediatric thin cortices and
spongiosa contributes to the aggressive behavior of the lesion .
The prognosis of chondromyxoid fibroma of the clavicle has not
been reported owing to its rarity. Clavicular tumors can be easily
discerned, and the clavicle is readily accessible for treatment.
Consequently, early diagnosis and en bloc excision of the tumor can
be expected, with the result that the prognosis of chondromyxoid
fibroma of the clavicle can be expected to be better than the
overall prognosis of chondromyxoid fibroma . In our case,
intraoperative histological extemporaneous reading of the biopsy
sample was able to arrive at the definitive diagnosis of CMF. The
management was then curettage with phenol treatment and
synthetic processed bone grafting. Recurrence was not observed 5
years after the operation. However, a careful follow-up is required
because of the possibility of recurrence as our patient was 7 years
at the time of diagnosis.
We report a case of chondromyxoid fibroma arising from
one-third distal end of the right clavicle of a 7-year-girl. This is
an additional patient with this rare tumor in this very unusual
anatomic location. The clinical and imaging features alone are
non-specific, and the definitive diagnosis relies on pathological