Osteosarcoma of the proximal part of the radius in Mazabraud syndrome. A case report

Fibrous Dysplasia/McCune-Albright Syndrome: A Rare, Mosaic Disease of Gα s Activation

Fibrous dysplasia/McCune-Albright syndrome (FD/MAS) is a rare disorder of striking complexity. It arises from somatic, gain-of-function mutations in GNAS, leading to mosaic Gα s activation and inappropriate production of intracellular cyclic adenosine monophosphate (cAMP). The clinical phenotype is largely determined by the location and extent of affected tissues, and the pathophysiological effects of Gα s activation within these tissues. In bone, Gα s activation results in impaired differentiation of skeletal stem cells, leading to discrete skeletal lesions prone to fracture, deformity, and pain. Extraskeletal manifestations include a variable combination of hyperpigmented macules and hyperfunctioning endocrinopathies. Distinctive age-related changes in disease development has key effects on histologic, radiographic, and clinical features. FD/MAS thus presents along a uniquely broad clinical spectrum, and the resulting challenges in diagnosis and management can be difficult for clinicians. This review presents FD/MAS in the context of a mosaic disorder of Gα s activation, providing an intellectual framework within which to understand, evaluate, and treat this interesting disease. It includes a comprehensive summary of current understanding of FD/MAS pathogenesis, and a detailed discussion of clinical presentation and management. Critical areas of unmet need are highlighted, including discussion of key challenges and potential solutions to advance research and clinical care in FD/MAS.

Osteosarcomatous Transformation in the Setting of Mazabraud's Syndrome: A Case Report and Review of the Literature

Introduction

Mazabraud's Syndrome is a rare condition that is defined by the presence of fibrous dysplasia lesions in the bone and intramuscular myxomas in the soft tissue. Malignant transformation, in the setting of Mazabraud's Syndrome, of the fibrous dysplasia lesions into a sarcomatous neoplasm occurs in less than 1% of cases-with only six previously reported cases.

Case Presentation

Here, we present a 62-year-old Caucasian female who developed an osteosarcoma in a fibrous dysplasia lesion of the proximal femur in the background of Mazabraud's Syndrome. The patient was treated with wide excision and endoprosthetic reconstruction. She declined adjuvant chemotherapy. She is alive without evidence of disease one-year postoperatively.

Conclusion

Patients with Mazabraud's Syndrome remain at low risk for malignant transformation. However, close monitoring of asymptomatic patients with this condition for radiographic changes in their lesions and/or clinical symptoms is recommended.

[Mazabraud and McCune-Albright syndromes in association : A case of two very rare orthopaedic tumour entities]

We report on a 47-year-old woman with unilateral fibrous dysplasia and three intramuscular masses. Medical imaging revealed possible intramuscular myxomas, so that the suspected diagnosis was Mazabraud syndrome. After biopsy, the suspected diagnosis was verified by histology and molecular pathology. Due to endocrine abnormalities in the patient's medical history, McCune-Albright syndrome has was also verified.

Resection of a Giant-Cell Tumor of the Proximal Aspect of the Radius with Osteoarticular Allograft Reconstruction: A Case Report

CASE

Giant-cell tumors are locally aggressive osteolytic benign tumors that are characterized by multinucleated giant cells. Recurrence rates are ≤30% after curettage and <5% after resection, but reconstruction can be difficult. We describe an osteoarticular allograft reconstruction of the proximal aspect of the radius in a 23-year-old man after resection of a giant-cell tumor.

CONCLUSION

Five months after surgery, the patient had satisfactory joint articulation, range of motion, and strength, with no signs of hardware or graft failure. By 17 months, there was complete osseous union. The joint remained stable at 54 months. We describe our surgical approach, which restores joint stability and minimizes recurrence.

Chondrosarcoma of the femur in Mazabraud's syndrome: A first case study

Malignant transformation of fibrous dysplasia (FD) in long bones is rare (less than 1% of cases) and occurs in the form of osteosarcomas. They can occur on FD associated with multiple myxomas, which corresponds to Mazabraud syndrome. To our knowledge, only six cases of FD malignant transformation into osteosarcoma in the context of Mazabraud syndrome have been described. Here, we describe the first case of malignant transformation of femur FD into chondrosarcoma in a 51-year-old female patient. The patient had significant changes in the size and number of myxomas around the femur before the malignant transformation into chondrosarcoma. She underwent complete femur replacement with a favourable result after 4 years' follow-up. Close surveillance is strongly recommended in this syndrome, particularly when the number and size of myxomas increase.

Combined composite osteofasciocutaneous fibular free flap and radial head arthroplasty for reconstruction of the elbow joint

Reconstruction of the radial head can be complicated in cases of wide resection, particularly in those cases including the proximal radial shaft. In such cases, radial head replacement may not be possible because of lack of adequate bone stock. Here, we report the use of a radial head prosthesis incorporated with a vascularized fibula for immediate anatomic restoration of the forearm and elbow. We present a case of a pathologic fracture non-union in the proximal radius in a 57-year-old female with a history of multiple myeloma. Non-operative management of the fracture was unsuccessful after chemotherapy and radiation. The proximal radius and radial head were resected and reconstructed with vascularized fibula graft in conjunction with immediate radial head prosthesis. The osteotomy site healed at 6-weeks and follow-up at 1 year showed good functional outcome. We feel that the use of this construct has definite promise and may be considered for reconstruction following resection of the proximal radius.

An atypical monomelic presentation of Mazabraud syndrome

Mazabraud syndrome is a rare condition characterized by a combination of fibrous dysplasia and intramuscular myxomas. In Mazabraud syndrome, the distribution of fibrous dysplasia is mostly polyomelic and frequently located in the femur, with myxomas adjacent to the fibrous dysplasia lesion of bone (mostly in the quadriceps muscle). However, when presented as atypical clinical features, patients of Mazabraud syndrome is either misdiagnosed or difficult to diagnose. We report an atypical monomelic case of Mazabraud syndrome in the right upper arm and discuss the difficulties in making an accurate diagnosis.

Mazabraud's syndrome: case report and literature review

Mazabraud's syndrome is a rare disorder characterized by the association of single or multiple intramuscular myxomas with fibrous dysplasia. Here, we present the first case of Mazabraud's syndrome visualized on 18F-FDG PET/CT with histopathological confirmation of the myxoma. Our case demonstrates a slightly increased FDG uptake (SUVmax 2.1) within the myxomas and a moderately to highly increased tracer uptake (SUVmax 7.0) within the fibrous dysplastic lesions. The typical histological appearance of the intramuscular myxoma confirmed the radiological diagnosis. Further, we discuss the imaging findings and the histopathological features of this rare case with a review of the related literature.

Mazabraud's syndrome. A case with multiple myxomas

Mazabraud's syndrome is defined as the combination of one or more intramuscular myxomas and fibrous dysplasia of bone. The diagnosis is important given the increased risk of malignant transformation of the bone lesions. We report a case in a 56-year-old patient with a 14-year follow-up during which multiple surgical procedures were required to remove myxomas (present at more than 15 sites). The resected myxomas were large and progressive. Unique features in this case include the long follow-up and the number of myxomas considerably above the average for this disease. Eighty other cases of Mazabraud's syndrome have been reported. The condition predominantly affects middle-aged women (mean age, 44 years). The bone lesions may be monostotic or polyostotic. Mazabraud's syndrome may be difficult to distinguish from soft-tissue sarcoma or neurofibromatosis. Identification of the underlying genetic abnormality provides diagnostic confirmation, as shown in our patient. The management consists in surgery to remove the myxomas and magnetic resonance imaging at regular intervals to monitor the lesions.

Composite reconstruction after proximal radial giant cell tumor resection

Giant cell tumor (GCT) of bone involving the proximal radius is extremely rare. Here, the authors present the case of a 33-year-old man with an expansile, osteolytic lesion in the proximal radius, which was diagnosed by biopsy as GCT. The rarity of this lesion in the proximal radius is highlighted, and the authors describe their method of reconstruction, which involved en-bloc excision followed by reconstruction with polyethylene, pins, a screw, and bone cement. An acceptable intermediate term result was achieved.

Use of metal proximal radial endoprostheses for treatment of non-traumatic disorders

We have reviewed five adult patients treated with endoprosthetic reconstruction of the proximal radius following resection of non-traumatic lesions. The patients had a mean age of 33.4 years (20 to 60) at the time of surgery and the mean follow-up was 7.6 years (0.8 to 16).

Following surgery, all elbows were clinically stable and there was 100% survivorship of the prosthesis. Evaluation of function was assessed clinically and by the Mayo Elbow Performance Score, achieving a mean of 86% (70 to 100).

Results at medium-term follow-up are encouraging with regards to elbow stability, implant survivorship and functional outcome.