EJVES Short Reports (2016) 33, 27e31

CASE REPORT

Thrombosed Popliteal Artery Pseudoaneurysm as Herald of TibialOsteochondroma

A.M. Ruales Romero *, E. Doiz Artazcoz, A. Craven-Bartle Coll, A. Gonzalez Calbo, M. Rodríguez Piñero

Hospital Universitario Puerta del Mar, Cadiz, Andalucía, Spain

* Code ViyE-ma2405

EuropeCC BY-http

Background: Osteochondroma is the most common non-malignant tumour of bone, accounting forapproximately one third of benign lesions in the skeleton. They often develop around the knee in the distal femurand in the proximal tibia and fibula. They present as a painless slow growing mass during adolescence and havebeen reported to cause damage to adjacent structures such as blood vessels; arterial damage is more commonthan venous injury and is usually a result of compression, stretching, and rubbing of the arterial wall. Such lesionsinclude stenosis, thrombosis, and pseudoaneurysm formation possibly causing lower limb claudication or acutelimb ischemia.Methods: An 18 year old male patient with a 4 week history of pain, hematoma, and oedema of the left calfwithout previous trauma is reported. A computed tomography scan (CT) revealed a large popliteal arterypseudoaneurysm and its close relationship to a protrusion of the proximal tibia.Results: The popliteal artery was repaired by an external saphenous patch and the exostosis was removed. Thepatient had palpable popliteal and distal pulses after surgery and during the first year follow-up.Conclusions: Tibial osteochondroma should be considered in the differential diagnosis in young patients, amongthe potential causes of pseudoaneurysm of the femoral or popliteal artery. Surgical repair should be performedto restore normal blood flow with resection of the exostosis to prevent recurrence.� 2016 The Authors. Published by Elsevier Ltd on behalf of European Society for Vascular Surgery. This is an openaccess article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Article history: Received 19 April 2016, Revised 19 September 2016, Accepted 21 September 2016,Keywords: Popliteal artery, Pseudoaneurysm, Tibial exostosis, Osteochondroma

INTRODUCTION

Arterial pseudoaneurysm is an encapsulated hematomacommunicating with the lumen of a ruptured artery. Itsformation mechanism, associated with bone exostoses, hasbeen well described in the literature.1e3 The distal superfi-cial femoral artery and the popliteal artery are the mostcommonly injured vessels because of their anatomicalproximity to the distal femur and proximal tibia, the mostcommon sites of osteochondroma formation.4 Vascular pa-thology results from repeated abrasions to the artery duringflexion of the knee, producing injury to the vessel wall,resulting in the formation of a pseudoaneurysm.5 Othercomplications caused by bony protrusions are less commonand include arteriovenous and nervous compression, arterialrupture, and stenosis. Clinical manifestations include painfulpulsatile mass associated with hematoma, functional ab-normalities, oedema, and neuropathic pain.4,5 Exostoses arethe most common benign tumours of bone. They account

rresponding author. Hospital Universitario Puerta del Mar, Ave. Anaa S/N, CP 11009 Cadiz, Andalucía, Spain.il address: anaruales@gmail.com (A.M. Ruales Romero).-6553/� 2016 The Authors. Published by Elsevier Ltd on behalf ofan Society for Vascular Surgery.This is an open access article under theNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).://dx.doi.org/10.1016/j.ejvssr.2016.09.004

for 10e15% of both benign and malignant bone tumours.4

Their prevalence is 2.5:1 male to female ratio during thesecond decade of life. However, as they are usually asymp-tomatic, their real incidence is probably higher.6 Patientsusually present during the second decade of life.

Arterial complications resulting from osteochondromamust be studied thoroughly, as this is an uncommon causeof limb ischemia. Complete physical evaluation includingdistal pulses at rest and with extension/flexion manoeuversas well as the presence of a hard pulsatile mass, shouldsuggest the diagnosis. Imaging includes duplex scanning toassess arterial structure and patency, plain radiographs, andmagnetic resonance imaging to evaluate bone lesions.1 Theuse of CT scan is a good option to appraise vessel injury andits possible relation to the exostosis. Surgical treatment isindicated in symptomatic patients and it includes arterialreconstruction and excision of the bony protuberance. Sur-gical removal of the tumour is indicated if it is adjacent tothe vessel, interferes with a joint, or if there is macroscopicor radiological suspicion of malignant transformation.1,5

This study presents the case of a young man with a largethrombosed popliteal pseudoaneurysm caused by a solitaryexostosis with a sharp tip in the proximal tibia, whounderwent surgical excision of the tumour and arterialreconstruction.

28 A.M. Ruales Romero et al.

CASE REPORT

An otherwise healthy 18 year old male presented with a 4week history of pain and oedema of the left calf, with noprior history of intermittent claudication, and no recenttrauma. Physical examination of the left lower extremityshowed a normal femoral pulse, with non-palpable popli-teal, dorsalis pedis, or posterior tibial pulses. A non-pulsatile hard mass was noted in the popliteal fossa.Peripheral capillary filling was normal, with normal motorfunction, diminished perception of pain, and coldness ofthe foot.

A radiograph showed a pedunculated exostosis on theproximal tibia (Fig. 1). Doppler ultrasonography reported ahematoma in the popliteal fossa (Fig. 2). CT scan revealed a

Figure 1. Lateral plain radiograph of left leg: sessile protrusionfrom the posterior surface of the proximal tibia.

Figure 2. Duplex scan: hypoechogenic mass in the popliteal fossa adpseudoaneurysm.

proximal tibial exostosis, and an 8 cm diameter largelythrombosed false aneurysm of the distal popliteal artery, inclose relation to a proximal tibial exostosis (Fig. 3). MRIshowed a unilateral lesion in the left tibia and no signs ofmalignancy of the soft tissue (Fig. 4).

Surgery was performed with the patient in the proneposition under epidural anaesthesia and sedation, by bothvascular and orthopedic surgeons. The pseudoaneurysmwas exposed through a posterior approach to the poplitealfossa. The proximal and distal popliteal artery was dissectedand controlled with vessel loops; dissection and resection ofthe pseudoaneurysm was performed as well as evacuationof the hematoma, to decompress adjacent neurovascularstructures. The exostosis was removed by the orthopedicsurgeon; the remaining bone edges were smoothed. Con-servative excision of the protrusion was determined fromthe benign appearance of the lesion and a tumour biopsywas sent for histopathological analysis. A single 3 mmdiameter orifice was found on the posterior wall of thepopliteal artery. The damaged vessel was repaired by lon-gitudinal arteriotomy and closure with an external saphe-nous vein patch (Fig. 5). Fasciotomy was required todecompress the muscular compartment.

Recovery was satisfactory; the patient was discharged 3days after surgery. Normal vascular status was restored, withpalpable distal pulses and less oedema in the left calf.Doppler ultrasonography performed 3 months later showednormal blood flow. The patient did not need physical reha-bilitation, as he made a full recovery resuming his regularactivities without any pain. Histologically, the resectedexostosis was composed of bone and cartilage with nomalignancy, confirming the diagnosis of osteochondroma.

jacent to the popliteal artery with characteristic yinyan image of

Figure 3. CT scan axial and sagittal view: 8 cm mass in contact with tibial exostosis.

Thrombosed Popliteal Artery Pseudoaneurysm 29

At 6 and 12 month follow-up the patient had completelyrecovered a full range of movements, presented normaldistal pulses, and had no residual pain or oedema.

DISCUSSION

Osteochondroma is one of the most common develop-mental lesions of the bone, accounting for 10e15% of bothbenign and malignant bone tumours.4 It may present as asolitary lesion or as hereditary multiple exostoses. The mostcommon location is the distal femur. Clinical manifestationsare usually absent, therefore the diagnosis is mostly inci-dental. Presenting complaints may include claudication oracute limb ischemia from stenosis, thrombosis, rupture of

pseudoaneurysm, distal embolisation, neuropathic pain andvein thrombosis caused by compression.6

Pseudoaneurysm formation is the most common as aresult of arterial injury caused by exostosis. It has beenhypothesised, that the bone exostosis causes intermittentchronic abrasion to the artery with flexion and extension ofthe knee joint, damaging the adventitia and leading to thefalse aneurysm.7,8 According to the literature there havebeen over 100 cases reported since the 1960s; 60% of thesewere in the distal femoral artery, 25% in the popliteal artery,and 15% in the distal vessels.2

The differential diagnosis of benign bone exostoses in thislocation that may potentially cause vascular damage areosteochondroma, subungual exostosis, turret and traction

Figure 4. MRI axial and sagittal view: the exostosis has continuity of tibial bone cortex with an overlying cartilage cap, in contact with thepseudoaneurysm.

30 A.M. Ruales Romero et al.

exostoses, bizarre parosteal proliferation, and florid reactiveperiostitis. Radiological features ofosteochondroma are oftenpathognomonic; the protuberance is composed of corticaland medullary bone with an overlying hyaline cartilage cap incontinuity with the underlying parent bone cortex.7 CT scanandMRI are useful for identifying and studying complicationsincludingmalignancy.Malignant transformation occurs in lessthan 1% of solitary osteochondromas.9

Surgical vascular reconstruction and excision of the adja-cent osteochondroma is considered to be the treatment ofchoice in symptomatic patients. Asymptomatic cases may befollowed up by careful medical observation and annual plain

radiographs.1 Ultrasound guided compression is not rec-ommended because of the high risk of aneurysm rupture.Endovascular treatment in this age group is not recom-mended because of its shorter durability.1,9 The use oftransarterial embolisation with helical microcoils has beendescribed, mostly in older hemodynamically unstable pa-tients but may also carry a risk of coil migration causingdistal embolisation.10

Surgical treatment by a multidisciplinary team includingvascular and orthopedic surgeons is often required to restorenormal vascular status and improve nerve compressionsymptoms. Conservative excision of the exostosis is

Figure 5. Intra-operative image showing exostosis of the tibialbone before its resection.

Thrombosed Popliteal Artery Pseudoaneurysm 31

recommended in macroscopically benign lesions, and histo-pathology analysis is required to evaluate the need ofadjuvant therapy post-operatively. Osteochondromas inadolescence may spontaneously recur, even after adequateresection, therefore annual radiographic follow-up ismandatory.5,9

The importance of correct treatment and follow-up oflarge osteochondromas to avoid complications such asfurther damage to neighboring neurovascular structures, andpotential malignant degeneration is emphasised. In youngpatients with symptoms of limb ischemia, it is important tostudy non-atherosclerotic causes of vascular diseaseincluding coagulation disorders, heart disease, trauma his-tory, and neoplasms such as the one in the case report. Post-operative care should include annual radiographic imaging toidentify other lesions or recurrence.

CONFLICT OF INTEREST

None.

FUNDING

None.

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