A sixteen-year-old male high-school student who worked part-time as a
butcher presented to a vascular surgeon with a six-week history of insidious
swelling in the left, non-dominant arm. The patient also complained of diffuse
brachial plexus paresthesias. He smoked one pack of cigarettes per year but
was otherwise healthy. A laboratory evaluation for thrombophilia revealed
normal findings. The family history was negative for hereditary bone tumors
and thromboembolism. A venogram revealed complete occlusion of the left
subclavian vein along with adjacent partial obstruction of the axillary vein.
Increased collateral venous drainage was present, suggesting external
compression. This finding was consistent with a primary subclavian thrombosis
resulting from thoracic outlet syndrome, also known as Paget-Schroetter
syndrome. Routine radiographs of the chest were initially interpreted as
normal, although a later retrospective review ultimately revealed the lesion.
Magnetic resonance images of the shoulder revealed no obvious extrinsic masses
compressing the lateral aspects of the subclavian vessels or brachial plexus,
although the medial aspects of these structures were not scanned. However,
possible anterior scalene hypertrophy was noted, suggesting a specific type of
thoracic outlet syndrome, namely, scalenus anticus syndrome. Thoracic outlet
exploration was considered but was not performed given the absence of a
definite extrinsic compression etiology. Interventional thrombolysis of the
subclavian vein failed because of a technical inability to access the occluded
vein. Anticoagulation therapy with Coumadin (warfarin) was instituted for one
year, without any change in symptoms; it was stopped thereafter because of its
inconvenience to the patient.
Three years after the onset of thrombosis, the patient was working
full-time as a butcher and presented to his chiropractor because of new
sternoclavicular pain and popping, which worsened with butchering duties that
required ballistic overhead movements and heavy lifting. A radiograph of the
shoulder revealed a conspicuous sessile osteolytic bone lesion on the medial
part of the clavicle, adjacent to the sternoclavicular joint
(Fig. 1). A retrospective
review of an initial chest radiograph that had been made three years earlier
also revealed this same lesion. There had been no obvious radiographic changes
during the three-year interval. The patient was referred to the orthopaedic
tumor service for further evaluation.
Physical examination revealed engorged veins throughout the proximal aspect
of the arm. The range of motion of the shoulder was full. The sternoclavicular
joint was tender, without a palpable mass. Forward flexion of the shoulder and
adduction of the arm generated an audible and palpable pop over the
sternoclavicular joint. The patient had full motor strength, a bounding radial
pulse, and diffuse altered sensation throughout the hand and forearm. Adson's
test was positive.
A computerized tomographic scan demonstrated an osseous tumor that was
located <5 cm lateral to the sternoclavicular joint and projected
posteroinferiorly toward the first rib
(Fig. 2). The cortical and
medullary continuity between the lesion and the host clavicle favored the
diagnosis of an osteochondroma, which is rarely found in the clavicle. Only 4
mm of space remained between the tumor and the first rib. These findings,
combined with the known subclavian thrombosis and brachial plexopathy, spurred
the hypothesis that an osteochondroma was creating a mass-effect compression
of the adjacent subclavian vessels and brachial plexus. Besides the typical
appearance of an osteochondroma, the computerized tomographic scan did not
reveal an obvious cartilage cap or soft-tissue mass, which would otherwise
have raised concern about malignant transformation.
The patient elected surgical decompression. An oblique clavicular osteotomy
was performed distal and lateral to the lesion. Elevation of the medial
clavicular fragment revealed a large, irregularly shaped osseous tumor
compressing the neurovascular structures. After elevation of adherent soft
tissues, the tumor was excised from the posterior aspect of the clavicle with
an oscillating saw. The clavicular osteotomy site was reduced and was secured
with lag screw-and-plate fixation (Fig.
3). The tumor measured 3.3 × 1.6 × 1.6 cm. The
cartilage cap was small and without evidence of malignant transformation. The
pathologic diagnosis was benign osteochondroma
(Fig. 4).
Soon after surgery, the brachial plexus paresthesias resolved but the
subclavian vein thrombosis with postphlebitic syndrome was clinically
unchanged. Dilated and tortuous collateral veins persisted over the
shoulder.
After three months of shoulder-strengthening rehabilitation, the patient
had full range of motion of the glenohumeral and sternoclavicular joints. He
no longer had crepitus or sternoclavicular popping. The clavicular osteotomy
site was painless and had healed radiographically by three months after
surgery, without complications (Fig.
3). The patient resumed light work and activities. Eight months
postoperatively, a repeat venogram revealed the persistence of subclavian and
axillary vein thrombosis, but with only partial obstructions, indicating some
degree of recanalization. As we do not know the precise time when the partial
recanalization of the subclavian vein occlusion occurred, we can only surmise
that it may have occurred sometime after surgery as a result of the thoracic
outlet decompression.