Clinicopathologic features, diagnosis, and treatment of malignant fibrous histiocytoma of bone

FGF23 Expression Is a Promising Immunohistochemical Diagnostic Marker for Undifferentiated Pleomorphic Sarcoma of Bone (UPSb)

Background: Undifferentiated pleomorphic sarcoma of bone (UPSb) is a rare primary bone sarcoma that lacks a specific line of differentiation. Distinguishing between UPSb and other malignant bone sarcomas, including dedifferentiated chondrosarcoma and osteosarcoma, is challenging due to their overlapping features. We have previously identified that UPSb tumours have elevated mRNA levels of Fibroblast Growth Factor 23 (FGF23) transcripts compared to other sarcomas including osteosarcoma. In the present study, we evaluated the specificity and practicality of FGF23 immunoreactivity as a specific diagnostic tool to differentiate UPSb tumours from osteosarcomas and dedifferentiated chondrosarcomas. Methods: A total of 10 UPSb, 10 osteosarcoma, and 10 dedifferentiated chondrosarcoma cases (all high-grade), were retrieved and immunohistochemistry for FGF23 was performed. Results: FGF23 protein was expressed at high levels in 80-90% of undifferentiated pleomorphic sarcoma of the bone cases, whereas it was expressed at significantly lower levels in dedifferentiated chondrosarcoma and osteosarcoma cases. A semiquantitative analysis, considering the intensity of immunoreactivity, confirmed significantly elevated FGF23 expression levels in UPSb tissues compared to those observed in osteosarcoma and dedifferentiated chondrosarcoma tissues. Conclusions: The results we present here suggest that FGF23 immunohistochemistry may be a useful tool to aid in differentiating UPSb from morphologically similar malignant bone sarcomas, especially in situations where sampling is restricted and there is limited clinical information available.

Staging of Bone and Soft-tissue Sarcomas

The purpose of staging in orthopaedic oncology is to provide a framework for classifying tumors based on their risk of local recurrence and distant metastasis to guide treatment decisions. Two separate systems are commonly used to categorize bone and soft-tissue sarcomas. The Musculoskeletal Tumor Society system for bone sarcomas and the Enneking system for soft-tissue sarcomas are the original staging systems developed by orthopaedic surgeons. The American Joint Committee on Cancer staging systems for bone and soft-tissue sarcomas are periodically updated based on new data, and they are currently on their eighth edition.

Imaging findings, prevalence and outcome of de novo and secondary malignant fibrous histiocytoma of bone

OBJECTIVE

To evaluate the radiographic and magnetic resonance (MR) imaging features of primary and secondary malignant fibrous histiocytoma in bone and determine the demographics, prevalence and outcome of patients with this tumor.

MATERIALS AND METHODS

A retrospective search of files from two institutions identified 28 patients with malignant fibrous histiocytoma (MFH) of bone. Microscope slides were reviewed to confirm diagnosis and identify any pre-existing lesions. Medical records were reviewed with respect to patients' demographic characteristics and outcomes.

RESULTS

Radiographic features demonstrated an aggressive osteolytic lesion with a permeative pattern of bone destruction. Periosteal reaction was seen in three of 13 lesions. T1-weighted images (T1WIs) demonstrated signal intensity iso- to slightly hyperintense to muscle. T2-weighted images (T2WIs) demonstrated mildly higher signal intensity than that of muscle. The 5-year survival rate was 53%. The tumor arose secondarily in pre-existing lesions in 43% of patients. Metastases occurred in 46% of patients during the course of the disease, with pulmonary and osseous metastases being the most common.

CONCLUSION

Secondary MFH of bone was slightly less common than primary MFH and had a prognosis similar to that of primary MFH of bone. MR imaging showed variable and somewhat unusual low to intermediate T2 signal characteristics for a radiographically malignant osteolytic lesion.

Limb salvage surgery complimented by customised mega prostheses for malignant fibrous histiocytomas of bone

PURPOSE

To assess functional and oncological outcomes of patients with malignant fibrous histiocytomas of bone, after limb salvage surgery complimented by a customised prosthesis.

METHODS

Between May 1991 and December 2002, 15 men and 5 women (mean age, 42 years) with histologically proven malignant fibrous histiocytoma of bone underwent treatment involving limb salvage surgery complimented by a customised mega prosthesis. Most of the tumours were stage II according to the Enneking system, and located around the knee. Wide resection margins were achieved in 18 patients.

RESULTS

Following a mean follow-up of 58 months, 4 patients underwent amputation for local recurrence and 5 died of the disease. Two patients had prosthesis fractures; revision of the prosthesis was carried out in one. The functional result was excellent in 5 and good in 9 patients. The Kaplan-Meier 5-year survival rates of the patients treated without chemotherapy and with chemotherapy were 50% and 76%, respectively.

CONCLUSION

Limb salvage surgery with chemotherapy is a viable treatment option for patients with malignant fibrous histiocytoma of bone. It achieves higher survival rates than resection alone. Such therapy improves quality of life and provides a useful and functional limb.