Aneurysmal bone cyst secondary to a giant cell tumor of the patella: A case report

Reconstruction of the extensor mechanism using polypropylene mesh in a displaced pathological fracture of the patella affected by giant cell tumour

A man in his 30s came to our clinic with a year-long history of progressive pain and swelling in his knee. Diagnostic imaging revealed a displaced patellar fracture with an osteolytic, septated lesion and thinned expanded cortex in both fracture fragments. A core needle biopsy confirmed the diagnosis of giant cell tumour. Treatment involved wide excision of the tumour and the use of polypropylene mesh and a peroneal longus tendon autograft to reconstruct the extensor mechanism of the knee joint. One year postoperatively, the patient experienced no pain, demonstrated full range of motion and showed no signs of functional impairment or local tumour recurrence. This case highlights that reconstruction of the extensor mechanism of the knee after tumour excision with synthetic mesh is an affordable, user-friendly and widely accessible method. It can address large defects effectively while minimising the risks of disease transmission and graft lengthening, resulting in satisfactory outcomes.

Giant Cell Tumour of the Patella: A Missing Differential Diagnosis in the Young

Herein, we discuss the case of a 26-year-old male patient with a diagnosis of giant cell tumour (GCT) of the patella which is an exceptionally uncommon condition. The motive of reporting a rare case such as the giant cell tumour of the bone (GCTB) relies on its diagnostic incidence. Since the symptoms of this tumour overlap more common etiologies than GCT, the diagnosis of such a devastating malignant tumour is usually missed and hence delayed, which leads to poor treatment strategies and ultimately an irreversible fatal outcome. 

Mechanisms of acute hypercalcemia in pediatric patients following the interruption of Denosumab

PURPOSE

Denosumab is a fully human monoclonal anti-RANK-L antibody that is clinically used to counteract the bone loss induced by exacerbated osteoclast activity. Indeed, its binding to RANK-L prevents the interaction RANK-L/receptor RANK that is essential for osteoclastogenesis and bone resorbing activity. Although there are many medications available to treat bone loss diseases, including bisphosphonates, Denosumab is highly effective since it reduces the bone erosion. The use in pediatric patients is safe. However, some concerns are related to the interruption of the treatment. Indeed, in this study, we reported hypercalcemia in two pediatric patients and alterations of circulating osteoclast precursors.

METHODS

Peripheral Blood Mononuclear Cells (PBMC) were isolated from two pediatric patients with hypercalcemia after Denosumab interruption and from 10 controls. Cytofluorimetric analysis and in vitro osteoclastogenesis experiments were performed.

RESULTS

Increase of CD16^-CD14⁺CD11b⁺ cells was revealed in PBMC from patients reflecting the enhanced in vitro osteoclastogenesis.

CONCLUSION

Our data suggest that precautions must be taken when Denosumab therapy is interrupted and gradual decrease of dose and/or timing of treatment should be performed. To prevent the onset of hypercalcemia that could be in the discontinuation phase, cytofluorimetric analysis of PBMC should be performed to evaluate osteoclast precursors.

Atraumatic groin pain secondary to an aneurysmal bone cyst: A case report and literature review

BACKGROUND

Bone lesions can present the multi-displinary team with a challenge by way of diagnosis as some lesions share many radiological and histological characteristics. Giant cell tumours of the bone (GCTB) are relatively common, benign bone tumours. Aneurysmal bone cysts (ABC) are less common benign osteolytic lesions that are histologically similar to GCTBs but produce blood filled cavities. Both GCTBs and ABCs are locally aggressive and are typically found on meta-epiphyseal regions of long bones with pelvic tumours being less common.

CASE SUMMARY

A 17-year old female presented with atraumatic right groin pain and was initially diagnosed with a GCTB on the right superior pubic ramus of the pelvis. The patient was treated successfully with a wide excision, curettage and bone graft and underwent open reduction and internal fixation of the right hemi-pelvis. Following further intra-operative histological investigations, the lesion was diagnosed as an ABC.

CONCLUSION

This patient has had an uncomplicated post-operative course, has returned to comfortable weight bearing and will be reviewed for minimum 5 yr in the out-patient setting to monitor for reoccurrence.

Secondary aneurysmal bone cysts and associated primary lesions: imaging features of 49 cases

PURPOSE

To describe the imaging, anatomic, and clinical features of a series of secondary aneurysmal bone cysts (ABC) and to ascertain their most commonly associated primary bone lesions.

METHODS

Forty-nine cases of histopathologically proven secondary ABCs were retrospectively reviewed. Demographic data and clinical history were obtained. Radiographic, computed tomographic, magnetic resonance, and nuclear medicine imaging were analyzed. Lesion location, imaging characteristics, and associated primary lesions were documented. Linear regression analysis and Chi-squared testing was performed for statistical analysis.

RESULTS

Twenty-four males and 25 females were included, with an age range of 8-79 years (mean 29.7 + - 4.5 years). Eleven types of primary bone lesion were identified, with giant-cell tumor (n = 17, 35%), chondroblastoma (n = 11, 22%), fibrous dysplasia (n = 6, 12%), osteoblastoma (n = 4, 8%) and osteosarcoma (n = 4, 8%) being the most frequent. The lesions involved chiefly the long bone epiphyses (n = 25, 51%). Secondary ABC imaging findings and locations most closely approximated those of their primary counterparts, although fluid-fluid levels were seen at a higher frequency than previously reported in primary chondroblastoma (9/11, 82%), fibrous dysplasia (2/6, 33%), osteoblastoma (4/4, 100%), osteosarcoma (3/4, 75%), and chondromyxoid fibroma (1/2, 50%).

CONCLUSION

The most common primary lesions associated with secondary ABC were giant cell tumor and chondroblastoma, located in the long bone epiphyses. The majority of the secondary ABCs demonstrate predominant imaging characteristics typical of the primary bone lesions, but with a higher presence of fluid-fluid levels.

Giant Cell Tumor with Secondary Aneurysmal Bone Cyst of the Patella: A Case Report

A 15-year-old girl presented with pain and swelling on the anterior aspect of the right knee for one year. The radiological evaluation with x-rays and magnetic resonance imaging suggested a benign aggressive lesion of the right patella with a cortical breach. Core needle biopsy of the lesion revealed it to be a giant cell tumor (GCT). She was treated with total patellectomy and end-to-end repair of quadriceps to the patellar tendon. The histopathological report of the whole specimen revealed it to be a GCT with secondary aneurysmal bone cyst (ABC). After 24 months, she was asymptomatic, and there was no evidence of local recurrence or distal metastasis. An extensive review of the literature revealed only four cases of combined GCT with secondary ABC in the patella. Though rare, GCT with secondary ABC of the patella should be kept as a differential diagnosis for anterior knee pain and swelling in young patients. The diagnosis is solely based on histopathological findings. It is imperative to obtain a precise tissue diagnosis in the preoperative period to plan appropriate treatment. 

Recurrent multiple neurofibromatosis type 1 of the right lower limb

Neurofibromatosis type 1 is an autosomal dominant inherited disease, which is characterized by the presence of multiple neurofibromas. We encountered a case in which a sporadic dispersed neurofibroma recurred locally on numerous occasions extending over 16 years. The patient developed multiple masses with a focus of neurofibroma on the right lower limb, which were excised. The patient was initially diagnosed with inflammatory changes via computed tomography and magnetic resonance imaging; however, subsequently, pathological and immunohistochemical examinations revealed an intraneural neurofibroma. The patient underwent a comprehensive and complete local resection several times. After a continuous postoperative follow-up strategy, the patient recovered well. This report describes a case of primary manifestations of multiple and recurrent neurofibromas. We aim to emphasize the possibility of a unique, recurrent, non-healing neurofibroma and review the diagnostic techniques utilized to reach a definitive diagnosis. Early and complete surgical resection is an effective method to treat and prevent this type of neurofibroma.

Giant cell tumour of the patella with local recurrence: successful management with excision, curettage and artificial bone grafting

Primary patellar neoplasms are rare, comprising 0.12% of primary bone tumours; thus, no standardised treatment related to staging exists. 70%-90% of primary patellar neoplasms are benign or intermediate with giant cell tumour (GCT) being the most common. GCTs are locally aggressive, have a high recurrence rate and metastasise in 1%-2%. We report the case of a 23-year-old man with histologically confirmed recurrent GCT of the patella to demonstrate that aggressive surgical management options described in the literature, such as patellectomy with or without complex reconstruction, may be excessive and cause patients undue morbidity. Initially, the patient underwent intralesional curettage with excellent recovery, but presented again with a local recurrence within a year. A further definitive operation was performed which included excision of the inferior pole followed by curettage of the patellar body and artificial bone grafting. The patient made a good recovery and at 5-year follow-up has maintained good function.

Repeated Multiple Neurofibromatosis Type 1 in the Right Lower Limb: A Case Report

Neurofibromatosis type 1 (NF1) is an autosomal-dominant genetic disease characterized by the presence of multiple neurofibromas. We encountered a unique case of NF1 that manifested as a recurrent soft tissue neurofibroma in the right lower limb that developed over a period of 16 years. The patient presented with a painless mass that was initially diagnosed as inflammatory changes via computed tomography and magnetic resonance imaging. However, the condition was subsequently diagnosed as an intraneural neurofibroma via pathological and immunohistochemical examination, which showed a focal to patchy lymphocytic chronic inflammatory infiltrate and several non-encapsulated masses with clear boundaries that were easily distinguishable from the adjacent neurofibroma. The mass relapsed three times over 3 years since it was discovered, for which the patient underwent comprehensive and complete local resection several times. Postoperative continuous follow-up confirmed that the patient recovered well. Early and complete surgical resection is an effective method for treating and preventing recurrent neurofibromas. However, because of the importance of pathologic examination in the diagnosis of such cases, this uncommon entity might be underreported in patients with NF1.