Is PET–CT an accurate method for the differential diagnosis between chondroma and chondrosarcoma?

Abstract

The differential diagnosis between chondroma and intraosseous chondrosarcoma is based on imaging and clinical exams, but only a biopsy can confirm diagnosis. The aim of this study was to evaluate the value of PET–CT in differentially diagnosing chondroma and chondrosarcoma. From October 2009 to May 2015, 36 patients with cartilaginous bone lesions in the extremities, 12 (33.3 %) men and 24 (66.6 %) women, were prospectively included in the study. Patients ranged in age from 21 to 68 years, with a mean age of 44 years. Lesions were located in the long bones: in the proximal humerus in 26 (72.2 %) patients, in the femoral shaft in 1 (2.7 %), in the distal femur in 7 (19.4 %), and in the proximal tibia in 2 (5.5 %). The SUVmax value of 2.0 was used to separate between patients submitted to surgery and patients submitted to observation. Among the 36 patients studied, 17 (47.2 %) had SUVmax ≤ 2.0, and they were diagnosed as chondroma and they were treated conservatively. Follow-up ranged from 14 to 76 months, averaging 38 months. Nineteen (52.7 %) patients with SUVmax >2.0 were diagnosed as chondrosarcoma and underwent surgery. The area of the curve, calculated considering the SUV variable as numeric, is estimated in 0.966, with a 95 % confidence interval from 0.906 to 1.000. To evaluate the sensitivity, specificity and positive/negative predictive values, it was built a 2 × 2 table. Significance was set at p < 0.05. According the criteria of maximum sensitivity and specificity, the cut point suggested to SUVmax was 2.2. If we consider this point, it is possible to identify 19 of 36 positive cases to chondroma (52.8 %), it means, all chondrosarcomas of the series. We concluded that PET–CT can be used as an objective and quantitative method of differentiating between chondromas and chondrosarcomas located within the long bones. It represents a complementary examination to standard imaging (X-ray, scintigraphy, CT and MRI) and pathological exams. The SUVmax between 2.0 and 2.2 would be a range area between chondroma and chondrosarcoma and this range can be of value, among others exams, in decide the best treatment for patients with cartilaginous lesions in long bones.Level of evidence Level I—diagnostic study—prospectively investigating a diagnostic test using a universally applied “gold” standard.

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

“…In the participant selection domain, six studies were considered to be at low risk of bias [5,10,13,[25], [26], [27]. There was insufficient reporting to determine whether the participants were randomly or consecutively enrolled in seven studies [28], [29], [30], [31], [32], [33], [34]. We had excluded studies with a case-control design as our focus was on the effectiveness of selected imaging modalities in differentiating between chondrosarcoma and benign chondroid tumours.…”

“…In six studies [13,27,28,31,32,36], the index test was performed before the histological assessment hence we inferred that they did not have the knowledge of the reference standard. Eight studies relied on visual assessment of uptake [5,13,28,[30], [31], [32],36]. Nevertheless, it is the accepted general standard in nuclear medicine.…”

“…Nevertheless, it is the accepted general standard in nuclear medicine. In the reference standard domain, it was unclear whether assessors of the reference standard were blinded to the index test results in 11 studies [5,10,13,15,25,28,[30], [31], [32],36]. We considered a follow-up for longer than 12 months for benign tumours was sufficient to correctly identify them.…”

Laryngeal gout mimicking chondrosarcoma with concurrent longus colli tendinitis

“…Laryngeal gout was an unexpected diagnosis in our patient as he had a very high SUV of 7.7 on PET-CT scan which raised the suspicion of malignancy. PET-CT can be used to differentiate between chondromas and chondrosarcomas with an SUVmax of 2.0–2.2 as a discriminating threshold between the two 10. However, such nuclear imaging is not commonly used in gout, and few systemic publications exist.…”

The utility of 18F-FDG PET and PET/CT in the diagnosis and staging of chondrosarcoma: a meta-analysis

“…According to Laitinen et al's report enrolling 343 patients with osteochondroma, the concordance between the preoperative biopsy grading and the final post-surgical histologic diagnosis was observed in only 43% cases [10]. Conventional imaging methods such as X-ray, computed tomography (CT) scan, magnetic resonance imaging (MRI), and bone scintigraphy have been used as adjuvants for evaluating patients with suspected chondrosarcoma but often result in false negatives or false positives [11,12]. F-fluorodeoxyglucose ( 18 F-FDG) avidity provides useful information regarding tumor biology and sarcomatous transformation by depicting glucose metabolism and identifying hypermetabolic foci [13].…”