Imaging Characteristics of Primary Tumors of the Rib in Radiography, CT, and MRI to Differentiate between Benign and Malignant Lesions

 

Purpose or Learning Objective: To determine retrospectively the imaging characteristics of primary tumors of the ribs with radiography, computed tomography (CT), and magnetic resonance imaging (MRI) to differentiate between benign and malignant lesions.

Methods or Background: In a retrospective study, 124 patients with primary tumor of the rib were included after metastases had been excluded. In addition to epidemiological data, clinical parameters, such as comorbidity, pack-year, and local pain symptoms, were collected from all patients. A total of 179 lesions were analyzed for morphological features in radiography, CT, and MRI: localization, tumor size and extension, lytic or sclerotic appearance, and signal characteristics in MRI. The images were evaluated by a radiologist with > 5 years of experience in musculoskeletal imaging. The data collected were analyzed statistically concerning distinctive features between malignant and benign tumors.

Results or Findings: In this study, primary tumors of the rib were more often benign than malignant (74%) without a significantly different sex distribution. Lesions occurring in patients with a positive history of smoking and those causing local pain have a significantly higher risk of malignancy (p < 0.01). With regard to localization, no significant difference between benign and malignant lesions could be determined (p = 0.097). Less than half of both benign (41%) and malignant lesions (45%) were clearly identified on radiography. In CT and MRI, primary malignant tumors were larger on average, showed more frequent infiltrative growth (p < 0.01), and led to a pathologic fracture more often (p < 0.01). Osteolysis was more common in malignant tumors, whereas osteoplastic growth was more common in benign tumors (p < 0.01). Marginal sclerosis, in contrast, showed no significant difference between the two groups (p = 0.116). Also, contrast enhancement cannot be used to clearly differentiate between malignant and benign lesions (p = 0.061).

Conclusion: If there is no local pain, the clinical differentiation between primary benign and malignant tumors of the rib is extremely difficult. However, some imaging characteristics allow for a reliable assessment of malignancy, particularly when CT and MRI are combined.

Publication History

Article published online:
02 June 2022

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