Clinical evaluation and management of benign soft tissue tumors of the extremities

Diagnostic accuracy of functional imaging modalities for chondrosarcoma: A systematic review and meta-analysis

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Functional imaging modalities may have an important role in diagnosing chondrosarcomas.

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PET is a sensitive and specific test for differentiating chondrosarcomas and benign chondroid tumours.

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Thallium-201 scintigraphy has a high positive predictive value for chondrosarcomas.

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DMSA (V) has a 100% negative predictive value and can be used to rule out chondrosarcomas.

Introduction

The distinction between low-grade (grade 1) chondrosarcoma and its benign counterparts can be challenging. This systematic review aims to quantify the diagnostic accuracies of all functional imaging modalities used in the diagnosis of chondrosarcoma.

Methods

Medline and Embase were searched in February 2019. We included studies of either retrospective or prospective design if the results of functional scans were compared with pre-determined reference standards. Studies had to be primary diagnostic reports on patients with chondral tumours at first diagnosis. Two review authors independently performed study selection, extracted data and assessed the methodological quality. We calculated diagnostic accuracy measures for each included study.

Results

Four functional imaging modalities were identified across thirteen studies that met the inclusion criteria. 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography (FDG-PET) was a sensitive and specific test. Technetium-99 m with methylene diphosphonate (Tc-99 m MDP) had an overall low specificity of 4%. Thallium-201 scintigraphy demonstrated high positive predictive values across the studies. The negative predictive values of Technetium-99 m pentavalent dimercaptosuccinic acid (Tc-99 m DMSA (V)) were consistently 100%.

Conclusions

Low-grade chondrosarcomas continue to pose a diagnostic dilemma. FDG-PET demonstrated superior diagnostic accuracy compared to Tc-99 m MDP, Thallium-201 and Tc-99 m DMSA (V). Characteristic uptake patterns of Thallium-201 and Tc-99 m DMSA (V) may provide additional metabolic information to guide the diagnosis in this challenging group of tumours.

[General diagnostic work-up for benign tumors of the musculoskeletal system]

INTRODUCTION

Benign bone tumors are heterogeneous and have different biological behaviors. Treatment requires knowledge of the principle diagnosis and clinical behavior to avoid, on the one hand, overtreatment and, on the other hand, incorrect diagnosis of a potentially malignant tumor.

METHODS

Bone tumors of stage I (according to Enneking) should be observed clinically and radiologically. For stage II and stage III lesions, a biopsy should be performed, based on the corresponding oncological guidelines.

RESULTS AND CONCLUSION

Soft tissue tumors have a different radiological behavior (especially in magnetic resonance images): while a lack of sharp cortical margins in bone tumors indicates an aggressive behavior, sharp margins in soft tissue tumors should not be misinterpreted as benign tumors. Subfascial soft tissue tumors, tumors larger than 2 cm, growing tumors, and persisting tumors after trauma require biopsy.