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Primary bone tumors. MR morphologic appearance correlated with pathologic examinations
R Golfieri1, H Baddeley, J S Pringle
1Paul Strickland Scanner Centre, Mount Vernon Hospital, Northwood, Great Britain.
Abstract:
Eighty-three MR studies for primary bone tumors, performed with both spin echo and short time inversion recovery (STIR) sequences, were reviewed. Twenty-six patients underwent surgery within 10 days after MR imaging. Specimens were cut and directly compared with MR images. In the remainder, pathologic slides were compared in order to obtain a better understanding of MR pattern. All MR images were examined with a traditional morphologic approach and, upon comparison with surgical macroslides and with pathology samples, some MR distinctive patterns were identified: the bulky appearance of osteosarcoma surrounded by muscle edema, the multilobular high signal intensity (SI) chondroid lesions, the subtle infiltration of Ewing's sarcoma, rarely accompanied by muscle edema and prone to MR underestimation, the well defined "multiple shells" pattern of giant cell tumor, and the ill defined "storiform" appearance of malignant fibrous histocytoma are all typical MR features strictly corresponding to pathologic findings. The chondroid origin tumors may be identified based on the lobular high SI pattern whereas a benign fibrous lesion was the only one in this series to be distinguished relying on the SI. Peritumoral soft tissue edema was found by the STIR sequence only in malignant tumors (69%) of this series, and particularly in osteosarcoma (96%), chondrosarcoma (83%), and giant cell tumor (100%): this associate finding may further contribute to the diagnosis.
Insights
Magnetic resonance imaging (MRI) reveals distinct patterns for primary bone tumors. Short TI inversion recovery (STIR) sequences help identify malignant tumors by detecting peritumoral edema.
Area of Science:
- Radiology
- Oncology
- Pathology
Background:
- Accurate diagnosis of primary bone tumors is crucial for effective treatment planning.
- Magnetic resonance imaging (MRI) is a key modality for evaluating bone tumors, but specific pattern recognition is essential.
- Distinguishing between benign and malignant bone lesions can be challenging based solely on imaging.
Purpose of the Study:
- To identify and characterize distinctive MRI patterns of various primary bone tumors.
- To correlate MRI findings with surgical and pathological results for improved diagnostic accuracy.
- To evaluate the utility of short TI inversion recovery (STIR) sequences in differentiating tumor types and detecting malignancy.
Main Methods:
- Retrospective review of 83 MRI studies (spin echo and STIR sequences) for primary bone tumors.
- Direct comparison of MRI images with surgical specimens in 26 patients.
- Correlation of MRI patterns with histopathological findings in the remaining cases.
Main Results:
- Distinct MRI patterns were identified for osteosarcoma (bulky appearance, muscle edema), chondroid tumors (multilobular high signal intensity), Ewing's sarcoma (subtle infiltration, prone to underestimation), giant cell tumor ('multiple shells'), and malignant fibrous histocytoma ('storiform').
- Chondroid origin tumors were identified by lobular high signal intensity; a benign fibrous lesion was distinguished by signal intensity alone.
- Peritumoral soft tissue edema, detected by STIR, was present in 69% of malignant tumors (osteosarcoma 96%, chondrosarcoma 83%, giant cell tumor 100%), aiding in diagnosis.
Conclusions:
- Specific MRI features correlate well with pathological findings, enabling the differentiation of various primary bone tumors.
- The presence of peritumoral soft tissue edema on STIR sequences is a significant indicator of malignancy, particularly in osteosarcoma, chondrosarcoma, and giant cell tumors.
- Integrated analysis of morphological patterns and edema detection enhances diagnostic confidence in primary bone tumor evaluation.