Keywords
chondromyxoid fibroma - clavicle - disappearing bone
Introduction
Chondromyxoid fibroma (CMF) is a relatively rare bone tumor of cartilaginous origin
and comprises less than 1% of all primary bony tumors.[1] Clavicle is an unusual site of involvement for any bone tumor and may produce diagnostic
dilemma. Approximately 1% of all primary bone tumors may involve the clavicle.[2]
[3] In a review of 48 cases of clavicular tumors over a 50-year period, Smith et al
did not observe even a single case of CMF in the clavicle.[3] Another review of 12 patients with primary tumor or tumorous lesions of the clavicle
over 10 years did not feature CMF.[2] The present case was unusual as the lesion initially involved diaphysis of the clavicle
and this part of the bone gradually disappeared on radiographs. We suggest that CMF
should be included as one of the differentials of disappearing bone disease.
Written, informed consent was obtained from the parents authorizing radiological and
photographic documentation and they were also informed that data concerning the case
might be published in print and/or electronic form.
Case Report
A 13-year-old Indian girl presented with the complaints of pain and swelling over
the left clavicle for past 8 months. Pain was insidious in onset, gradually progressive,
nonradiating, and dull aching in nature. No diurnal variation was observed. It used
to get relieved on rest and taking oral analgesics, and aggravated with activities
of the left arm. The parents also noticed diffuse swelling/fullness in the region
that was limited to middle and medial third of the clavicle. These complaints were
associated with fever around 2 months before presenting to us. The episode necessitated
admission in the medicine ward with the diagnosis of pneumonitis with subcutaneous
emphysema. Chest radiographs at that time showed bilateral upper zone opacities in
the lungs with hilar lymphadenopathy; however, left clavicle appeared normal. High
resolution computed tomography revealed bilateral multiple cavitary lesions in lungs.
She was given intensive care with intravenous antibiotics through central line and
was discharged after 1 month once she improved. One month later, she reported back
with rapid aggravation of the pain over the left clavicular region. Fresh radiographs
were obtained, but patient refused admission for further management. They came back
after 3 weeks for admission. There was no history of weakness in the affected limb,
discharge from the involved region, recent weight loss, anorexia, hemoptysis, pruritus,
seizures, or similar swellings elsewhere in the body. It was not associated with any
preceding history of trauma. Her family history was noncontributory.
On examination, the vitals were stable and there was no evidence of lymphadenopathy.
Her physical status was good. Local examination revealed tenderness and diffuse swelling
originating from medial two-third of left clavicle. Local temperature was normal.
Overlying skin was freely mobile. There were no scars or sinuses. Bony gap with abnormal
painful mobility in the middle of clavicle was also appreciable. Rest of the organ
systems were normal.
Plain radiograph obtained during her stay in intensive care unit was reported as having
no bony abnormality ([Fig. 1A]). The radiograph (obtained 2 months later) revealed areas of lysis in the middle
third of left clavicle ([Fig. 1B]). The latest radiograph (obtained 2 months and 3 weeks later) revealed a pathological
diaphyseal fracture with complete destruction of the middle third of clavicle with
surrounding osteopenia especially in the medial aspect ([Fig. 1C]). Though on retrospective analysis, it was noted that ill-defined lytic lesion was
appreciable in the first round of radiograph, which was missed. Computed tomography
revealed irregular outline of the medial two-third clavicle and lytic lesion in the
mid-shaft along breach in cortical continuity ([Fig. 2A–C]). There was no evidence of calcification. Surrounding osseous structures were unremarkable.
MRI revealed markedly irregular medial two-third clavicle that displayed altered signal
intensity appearing hypo- to isointense on T1-weighted imaging (T1WI) and hyperintense
on T2WI and short tau inversion recovery. Postgadolinium images revealed heterogenous
contrast enhancement along with ill-defined adjacent soft tissue component and surrounding
edema ([Fig. 3A, B]). There was no evidence of hemorrhage or necrosis. Laboratory examination revealed
leucocyte count (13,800/cumm), polymorphs 63%, lymphocytes 33%, monocytes 2%, and
eosinophils 2%. The erythrocyte sedimentation rate was 39 mm at the end of first hour
and C-reactive protein level was 2.3 mg/L. Kidney and parathyroid functions were normal.
Sputum examination was negative for acid fast bacilli. Enzyme-linked immunosorbent
assay test for human immunodeficiency virus I and II antibody was negative. The patient's
immune status was normal with no other focus of infection.
Fig. 1 (A) Plain radiograph taken in medical intensive care unit did not reveal obvious bony
abnormality. (B) Plain radiograph (taken 2 months later) showing areas of lysis in the middle third
of left clavicle. (C) The radiograph (taken 2 months and 3 weeks later) revealed a pathological diaphyseal
fracture with complete destruction of the middle third of left clavicle. There was
also presence of surrounding osteopenia especially in the medial third clavicle.
Fig. 2 Computed tomographic image: (A) axial section of soft tissue window; (B) axial section of bony window; (C) three-dimensional reconstruction image showing irregular outline of the clavicular
diaphysis, and lytic lesion with pathological fracture and soft tissue swelling.
Fig. 3 (A) T1-weighted magnetic resonance imaging (MRI) coronal image acquired following administration
of intravenous Gadolinium agent showing heterogenous contrast enhancement along with
ill-defined adjacent soft tissue component; (B) T2-weighted MRI axial image showing hyperintense signal intensity. Soft tissue component
was seen abutting the mediastinal fat in the prevascular space.
She underwent open biopsy under general anesthesia. Soft tissue component with overlying
pseudocapsule was dissected and excised. It was a fibrous structure without areas
of hemorrhage or necrosis. Curettage of the bone ends was performed. The entire tissue
was submitted for histopathological examination and culture. The histopathological
examination revealed predominantly low cellularity ([Fig. 4A]). Bland tumor cells were observed, at the periphery occupying the intertrabecular
spaces, with collagenous tissue ([Fig. 4A, B]). The tumor was composed of areas of fibrous tissue, chondromyxoid tissue in varying
proportions ([Fig. 4C–D]). The hypocellular areas were chondromyxoid that had multiple stellate shaped cells
with minimal pleomorphism ([Fig. 4D]). However, sclerotic shell at the periphery, haemosiderin laden macrophages, hyaline
cartilaginous tissue, and unlined blood filed spaces were not observed. There was
no evidence of calcification, necrosis, or hemorrhage. Cultures for pyogenic organisms
and microscopic examination for acid fast bacilli were negative. These findings were
considered consistent with fibrous predominant CMF.
Fig. 4 (A) Photomicrograph (stain, hematoxylin and eosin, original magnification, ×100) showing
the presence of hypocellular myxoid areas and scattered stellate cells. (B) Photomicrograph (stain, hematoxylin and eosin, original magnification, ×200) showing
predominantly low cellularity. Bland tumor cells are seen at the periphery occupying
the intertrabecular spaces, with collagenous tissue. (C) A high-power photomicrograph (stain, hematoxylin and eosin, original magnification,
×400) showing focal ABC like areas with increased cellularity. However, hemosiderin
laden macrophages, and unlined blood-filled spaces are not present. (D) A high-power photomicrograph (stain, hematoxylin and eosin, original magnification,
×400) showing lobulated chondroid areas with chondroid cells displaying minimal pleomorphism.
The patient underwent resection of the medial two-third of the clavicle with preservation
of the lateral third clavicle along with acromioclavicular complex. No reconstruction
was done. Resected specimen confirmed the biopsy diagnosis. Gradual shoulder mobilization
was started at 4 weeks and she was kept under regular follow-up on outpatient basis.
She was asymptomatic during latest follow-up at 22 months and had good shoulder function.
The repeat radiograph did not reveal any further disappearance of bone ([Fig. 5]). She had mild discomfort only on carrying heavy weights (like bucket full of water).
Fig. 5 Follow-up radiograph at 22 months postoperatively showing resected medial aspect
of clavicle.
Discussion
CMF of the clavicle is exceedingly rare and only seven cases bearing this diagnosis
have been reported in literature, to the best of our knowledge[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11] ([Table 1]). This includes a case out of total 36 cases of CMF reported by Zillmer and Dorfman
over 22 years,[9] and another out of 278 cases of CMF reported by Wu et al over the period of 88 years.[8]
Table 1
The details of reported cases of chondromyxoid fibroma of the clavicle
|
Authors
|
Age/
sex
|
Involved region in clavicle
|
Radiological features
|
Treatment
|
Follow-up
|
|
Zillmer and Dorfman[9] (1989)
|
One out of 36 reported cases of chondromyxoid fibroma had involvement of clavicle.
However, a detailed workup of the case was not published
|
|
Wu et al[8] (1998)
|
One out of 278 reported cases of chondromyxoid fibroma had involvement of clavicle.
However, a detailed workup of the case was not published
|
|
Nakazora et al[5] (2003)
|
34/ F
|
Diaphysis
|
Radiographs and CT: an osteolytic lesion with cortical thinning and expansion with
partial destruction at the diaphysis
MRI: a homogeneous iso-signal intensity mass in T1WI and a heterogeneous high-signal
intensity in T2WI
|
|
|
|
Pattamapaspong et al[6]
(2006)
|
23/M
|
Distal end clavicle
|
Radiograph: an expanded osteolytic lesion at distal end of the clavicle with well-defined
margins and internal septa
NCCT: expanded osteolytic lesion at the distal end of the clavicle with endosteal
scalloping, thin sclerotic rim and erosion of the inferior surface
MRI: not available
Tc-99m MDP bone scan: focal tracer uptake in distal end of the clavicle
|
Curettage with bone grafting
|
No recurrence at 37 months follow-up
|
|
Sakamoto et al[7]
(2006)
|
17/M
|
Lateral end of clavicle
|
Radiograph and NCCT: osteolytic lesion with cortical thinning, expansion and destruction.
High density areas of calcification were present
MRI: hypointense signal intensity on T1W and hyperintense signal intensity on T2WI
in intramedullary space with soft tissue extension
|
Extended curettage with phenol followed by bone grafting
|
No recurrence at 12 months follow-up
|
|
Khan
et al[4]
(2008)
|
6/F
|
Medial end of clavicle
|
Radiograph: large osteolytic area involving whole of medial end of clavicle with resorption
of superior cortical margins of medial end
NCCT: extensive lytic lesion in medial end of clavicle with breach in posterior cortex
and a soft tissue shadow
MRI: globular soft tissue component with no involvement of the underlying neurovascular
bundle
|
Wide excision
|
No recurrence at 2 years follow-up
|
|
Aggarwal et al[10] (2012)
|
84/M
|
Lateral end of clavicle
|
Radiograph: eccentrically placed osteolytic lesion in the lateral end of clavicle
MRI: 4.3 × 3.7 × 3 cm cystic solid lesion involving the lateral end of clavicle and
acromion process with cortical erosions and scalloping extending to acromioclavicular
joint.
|
En-bloc excision
|
No recurrence at 18 months follow-up
|
|
Hope et al[11] (2018)
|
7/F
|
Lateral end of clavicle
|
Radiograph: expanded, radiolucent, osteolytic lesion in the lateral end of clavicle
CT: thin sclerotic rim with endosteal scalloping measuring 2.9 cm × 1.3 cm. No calcification
or soft tissue mass
|
Curettage with phenol followed by synthetic processed bone grafting
|
No recurrence at 5 years follow-up
|
|
Present case
|
13/F
|
Medial two-third
|
Radiograph: a pathological diaphyseal fracture with complete destruction of the middle
third of the clavicle
CT: irregular outline of the medial two-third clavicle and lytic lesion in the mid
shaft along with breach in the cortical continuity
MRI: markedly irregular medial two-third clavicle which displayed altered signal intensity
appearing hypo- to isointense on T1WI and hyperintense on T2WI. Heterogenous enhancement
was evident on postgadolinium contrast images
|
Excision
|
No recurrence at 22 months follow-up
|
Abbreviations: CT, computed tomography; MDP, methylene diphosphonate; MRI, magnetic
resonance imaging; NCCT, noncontrast computed tomography; T1WI, T1-weighted imaging.
A careful clinical, radiological, and pathological correlation is necessary to arrive
at the correct diagnosis. CMF often display local aggressiveness radiologically, such
as cortical thinning, expansion, erosions, and destruction,[8]
[9]
[10] as was evident in our case.
The differential-diagnosis based on clinical and radiographic data included chronic
osteomyelitis, tuberculous osteomyelitis, malignant neoplasm (Ewing's sarcoma), benign
neoplasm (CMF/nonossifying fibroma), Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis
(SAPHO) syndrome, and chronic recurrent multifocal osteomyelitis. Considering the
radiological disappearance of bone, we additionally considered differential diagnosis
of Gorham's disease, osteolysis with nephropathy, hyperparathyroidism, and eosinophilic
granuloma.
Chronic infective etiology displays osteolytic lesions surrounded by sclerotic rim.[12] The absence of sequestrum, negative cultures, typical histopathological features
excluded the infective etiology. Other bony neoplasms could be ruled out by the absence
of typical histopathological features.[1]
[13] Other differentials of disappearing bone[14] could be ruled out by laboratory tests and the absence of typical histopathological
features.
The prognosis of CMF of clavicle has not been established because of the paucity of
literature[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11] ([Table 1]). It, however, appears good with early diagnosis and appropriate treatment as presented
in various case reports. Conventionally, it has been treated with curettage with or
without bone grafting/clavicular reconstruction. Approximately 20 to 25% cases of
the CMF of the various sites may recur following curettage and the figure may be slightly
higher in pediatric age-group.[1] However, such recurrences have not been observed in any of the reported cases of
CMFs of clavicle that may be attributed to the facts that clavicle is a subcutaneous
bone; its entire length and reconstruction may not be necessary following bone resection.
Phenol has been used as an adjunct to curettage to reduce local recurrence.[7]
High index of suspicion may be required for early diagnosis and treatment in such
patients. The diagnosis may be delayed owing to its indolent course, nonspecific symptomatology,
and unfamiliarity among orthopaedic surgeons with such atypical presentation. CMF
should be considered as a differential diagnosis of disappearing bone disease.
