A pathological fracture of the scaphoid revealing an intraosseous ganglion cyst

Intraosseous ganglion cyst is a benign bone lesion with histological similarities to the soft tissue ganglion cyst. Its location on the short bones, including the carpal bones has rarely been reported. The radiolucent carpal lesions are usually symptom-free found incidentally on radiographs of the wrist performed for other reasons. Detecting a pathological fracture of the scaphoid revealing an intraosseous ganglion cyst is exceptional. We report the case of a 21-year-old, right-handed male, presented with a one year history of progressive right-wrist pain, worsened since a month without a history of previous trauma. Plain radiographs and CT-scan revealed a cystic lesion of the scaphoid with a pathological fracture. He was successfully treated with curettage and packing with a Zaidemberg's vascularized radial graft without recurrence at two years postoperatively. Pan African Medical Journal. 2016; 23:185 doi:10.11604/pamj.2016.23.185.8188 This article is available online at: http://www.panafrican-med-journal.com/content/article/23/185/full/ © Mohamed Ali Sbai et al. The Pan African Medical Journal ISSN 1937-8688. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Pan African Medical Journal – ISSN: 19378688 (www.panafrican-med-journal.com) Published in partnership with the African Field Epidemiology Network (AFENET). (www.afenet.net) Case report Open Access


Introduction
Intraosseous ganglion cyst is a benign bone lesion with histological similarities to the soft tissue ganglion cyst.Its location on the short bones, including the carpal bones has rarely been reported.The radiolucent carpal lesions are usually symptom-free found incidentally on radiographs of the wrist performed for other reasons.Detecting a pathological fracture of the scaphoid revealing an intraosseous ganglion cyst is exceptional.

Patient and observation
A 21-year-old, right-handed male, without any pathological history, presented with a one year history of progressive right-wrist pain partially improved after receiving antalgic and anti-inflammatory treatment.Symptomatology has worsened since a month without a history of previous trauma.Clinical study revealed a moderate swelling over the palmar aspect of the wrist.Grip strength was decreased and wrist motion was slightly limited and painful at extreme ranges of motion.Plain radiographs of the right wrist revealed a round-shaped radiolucent lesion of the scaphoid with a thin marginal sclerosis and a pathological fracture (Figure 1).CTscan confirmed a cystic lesion of the scaphoid and was able to localize the lesion and the fracture precisely.Other carpal bones and adjacent joints were normal (Figure 2, Figure 3).The patient was operated using the anterior surgical approach of the scaphoid; both the scaphoid and the distal radius were exposed for harvesting vascularized bone.Through the defect on the volar aspect of the scaphoid, the cystic lesion was curetted out revealing atypical yellowish gelatinous material.The cavity was rinsed using a saline solution, then packed with a Zaidemberg's vascularized radial graft.After closing the joint capsule, the subcutaneous and cutaneous tissues, a removable wrist cast was applied for five weeks.Macroscopic and microscopic findings were characteristics of an intraosseous ganglion cyst (IGC).The patient was successfully treated surgically.The patient was completely relieved from pain with a slight limitation of the wrist motion and full grip strength, 3 months after operation (Figure 4, Figure 5).At the latest follow-up, two years postoperatively, plain radiographs show complete integration of the graft without recurrence (Figure 6, Figure 7).

Discussion
IGC is a benign bone tumor of osteolytic type.It usually develops in the epiphysis and metaphysis of long bones, mainly in the lower limbs.Its location on the short bones, including the carpal bones has rarely been described [1,2].To our knowledge, only 16 cases of IGCof the scaphoid have been reported in literature, only 3 of them were complicated by a pathological fracture [3].IGC of carpal bone is often asymptomatic.It is usually fortuitously discovered during a radiographs made for another reason.In other cases, it is the cause of chronic wrist pain triggered by repeated efforts, partially relieved by conventional analgesics.More rarely the diagnosis can be made by a displaced fracture complicating the IGC.This serious complication is usually post-traumatic and can cause irreversible damage.Plain radiographs typically reveal a well-defined osteolytic area outlined by a sclerotic rim.Differential diagnosis at this stage include chondroma, ostéochondroma, osteoid osteoma and preiser disease [4].Mnif [3] believes that CT-scan is an optional exam.Dumas [4] believes that it is useful for the diagnosis and to choose the surgical technique and approach, but it is also necessary for the assessment of fracture risk.Fracture risk depends on several morphological characteristics of IGC.Different stages of IGC in the short bones could be described: strictly intraosseous, single cortical infarction and displaced fracture.The cyst may also vary in size to fill the entire medulla.The fracture risk depends on the size of the intramedullary cavity and the size of the cortical defect [4].Anatomopathological study of the curettage material is necessary to confirm the diagnosis revealing a cystic wall covered with flattened fibroblast cells close to the synovial cells but without true epithelial lining.It is present in a typical yellowish gelatinous liquid [1,2].The choice of treatment depends on the clinical and the radiological study.Surgical treatment should be indicated if the IGC is symptomatic or if it is associated with high risk of fracture, to prevent this particular complication and within irreversible damage to the wrist [5].Treatment of IGC consists in the curettage of the cyst, injection of saline solution and packing the cavity with cancellous bone graft.In our case an anterior approach was preferred and a Zaidemberg's vascularized radial bone grafting was performed.

Conclusion
IGC of carpal bone is usually asymptomatic, fortuitously discovered, but could also be revealed by a pathological fracture with or without previous trauma.It is a serious complication that could cause irreversible damage.CT-scan is useful for the assessment of fracture risk.Curettage and packing with vascularized bone graft provides complete relief of pain with good functional result.

Figure 1 : 2 : 4 :Figure 5 :
Figure 1: Plain radiographs of the right wrist revealed a roundshaped radiolucent lesion of the scaphoid with a thin marginal sclerosis and a pathological fracture Figure 2: Coronal CT-scan confirmed a cystic lesion of the scaphoid and was able to localize the lesion and the fracture precisely.Other carpal bones and adjacent joints were normal Figure 3: Transverse CT-scan confirmed a cystic lesion of the scaphoid and was able to localize the lesion and the fracture precisely.Other carpal bones and adjacent joints were normal Figure 4: The patient was completely relieved from pain with a slight limitation of the wrist motion in flexion, 3 months after operation Figure 5: The patient was completely relieved from pain with full wrist motion in extension and full grip strength, 3 months after operation Figure 6: Two years postoperatively, antero-posterior view of the wrist showing complete integration of the graft without recurrence Figure 7: Two years postoperatively, lateral view of the wrist showing complete integration of the graft without recurrence

Figure 1 :
Figure 1: Plain radiographs of the right wrist revealed a roundshaped radiolucent lesion of the scaphoid with a thin marginal sclerosis and a pathological fracture

Figure 2 :
Figure 2: Coronal CT-scan confirmed a cystic lesion of the scaphoid and was able to localize the lesion and the fracture precisely.Other carpal bones and adjacent joints were normal

Figure 3 :
Figure 3: Transverse CT-scan confirmed a cystic lesion of the scaphoid and was able to localize the lesion and the fracture precisely.Other carpal bones and adjacent joints were normal

Figure 4 :
Figure 4: The patient was completely relieved from pain with a slight limitation of the wrist motion in flexion, 3 months after operation

Figure 5 :
Figure 5: The patient was completely relieved from pain with full wrist motion in extension and full grip strength, 3 months after operation

Figure 6 :
Figure 6: Two years postoperatively, antero-posterior view of the wrist showing complete integration of the graft without recurrence

Figure 7 :
Figure 7: Two years postoperatively, lateral view of the wrist showing complete integration of the graft without recurrence