Giant cell tumour of the distal humerus treated with elbow arthroplasty: A case report

Introduction: Giant cell tumour (GCT) of the distal humerus is very rare and the treatment depends on the grade of the tumour. Case Report: We present a 32­year­old lady with Grade III GCT of the left distal humerus treated with en bloc excision and custom made total elbow replacement. Her preoperative Mayo Elbow Performance Score was 30. At 56 months follow up, she is pain free with a Mayo Elbow Performance Score of 90 and no evidence of recurrence. Conclusion: Enneking’s staging and Campanacci’s radiographic grading helps in planning the treatment. When the lesion has violated a joint, en bloc excision followed by reconstruction or joint sacrifice is the treatment of choice. The options of reconstruction are auto or allografts, custom made endoprosthesis or allograft endoprosthetic composite. Reconstruction using autograft is seldom feasible in elbow. Allografts are met with high complication rates. Custom made total elbow arthroplasty is a good option especially for primary tumours of the elbow and can be done with good oncologic safety. Custom made total elbow arthroplasty is a good option for Campanacci Grade III GCT of the elbow. It provides excellent pain relief and good functional improvement with low complication rate.


INTRODUCTION
Giant Cell Tumour (GCT) of bone is a distinct clinicopathologic entity with distinguishing radiologic features. Although approximately 6% of the GCTs affect the humerus [1], GCT of the distal humerus is rare. We present a case of distal humerus GCT which had breached the cortex and was successfully treated with custom made total elbow arthroplasty and was prospectively followed up. Her general physical examination was within normal limits. Left elbow examination revealed a 5x4 cm oval swelling on the medial and anteromedial aspect of distal humerus obscuring the joint line. Swelling was warm, tender, with well defined edges, smooth surface, firm consistency and immobile. She had a flexion deformity of 40 degrees with a further flexion up to 90 degrees limited by pain and spasm. Full supination and pronation were present. Her blood investigations and chest radiographs were normal. Radiograph of the left elbow showed an eccentric lytic lesion of medial condyle of distal humerus which had breached the cortex. Mayo Elbow Performance Score was 30 at presentation. Bone scan showed intense uptake in the medial condyle of the distal humerus while rest of the skeleton was normal. Biopsy from the lesion revealed uniform ovoid mononuclear cells with numerous osteoclast type multinucleate giant cells which was consistent with GCT.

CASE REPORT
She was treated with en bloc resection of the distal humerus and custom made total elbow arthroplasty using 316 L SS, constrained, hinged cemented prosthesis. Postoperative period was uneventful and she was started on physiotherapy. Histopathologic examination of the three excised specimen showed one cm tumor free margin proximally while distally the tumor had breached the cortex and involved the soft tissues. She was prospectively followed up and on final follow up at 56 months she was pain free with flexion of 20110°and was able to carry out her personal and house hold works independently with a Mayo Elbow Performance Score of 90. There was no evidence of recurrence or metastasis.

DISCUSSION
GCT represents 48% of primary bone tumours. It is a locally aggressive benign bone tumour which occurs after the epiphyseal closure with a peak age of incidence in the 3 rd and 4 th decades [2]. GCT has a slight female preponderance and this is more in the paediatric and adolescent population [3].
GCT commonly affects the long tubular bones; the most common sites being distal femur and proximal tibia, distal radius, and proximal humerus, suggesting that in the lower extremity it tends to occur towards the knee; while in the upper extremity, away from the elbow [4]. Elbow per se is a rare site for primary bone   tumours. Only 1% of all primary bone tumours arise in the distal humerus [5]. Thus GCT of the distal humerus is a rarity.
Enneking's staging and Campanacci's radiographic grading helps in planning the treatment. It is important to stage the disease preoperatively with plain radiographs including chest Xray, MRI and biopsy. Enneking has classified benign bone tumours into latent, active and aggressive. Stage I (latent) and and II (active) are intracapsular while Stage III lesions (aggressive) are extracapsular extending into the soft tissues. On radiographs, GCT demonstrates a lytic lesion without mineralized tumour matrix, usually eccentric and shows a geographical pattern of destruction. Campanacci's radiographic grading roughly corresponds to Enneking's staging. Campanacci's Grade 1 is a cystic lesion with sclerosed margins, Grade 2 where the cortex is thin but not perforated and Grade 3 where the cortex is perforated. MRI is the investigation of choice to determine the tumour inhomogenity, intraarticular spread and soft tissue extensions. The transverse sections can differentiate GCT from other radiographically similar lesions [6]. Preoperative histopathologic examination helps in differentiating primary malignant GCT which often mimics conventional GCT clinically and radiologically and carries a poor prognosis [7].
Grade I and II lesions can be treated by joint preservation with good functional outcome and low recurrence rates. When the lesion has violated a joint, en bloc excision followed by reconstruction or joint sacrifice is the treatment of choice. The options of reconstruction are auto or allografts, custom made endoprosthesis or allograft endoprosthetic composite. Unlike distal radius, reconstruction using autograft is seldom feasible in elbow. Hemiarticular as well as total elbow allografts have been used in reconstructing the defects following tumour excision, but due to their high complication rates are mainly reserved as salvage procedure for failed elbow arthroplasty [8]. Custom made total elbow arthroplasty is a good option especially for primary tumours of the elbow and can be done with good oncologic safety [9]. It provides excellent pain relief and good functional improvement with low complication rates [10].
However, patients need to be followed up and evaluated periodically in terms of tumour recurrence, pulmonary metastasis or late malignant transformation of the residual tumour if any.

CONCLUSION
Giant cell tumor of the distal humerus is rare and a type III lesion at this site can be successfully treated with custom made total elbow arthroplasty, however, the patient needs to be followed up periodically. *********

Author Contributions
Azad Sait S -Acquisition of data, Analysis and interpretation of data, Drafting the article, Final approval of the version to be published