Tumours and tumour-like lesions of joints: Differential diagnoses in a paediatric population compared to adults

Abstract

Objective: To determine the differential diagnosis of intra-articular tumours and tumour-like lesions in a paediatric population compared to adults.

Methods: Retrospective review of children up to the age of 18 years with suspected intra-articular tumours and tumour-like lesions referred to a specialist musculoskeletal oncology service from January 2019 to August 2020. Data recorded included patient age and gender, lesion location and morphology (based on the classification system of Adams et al.), and the final diagnosis made either by image-guided biopsy/resection or by clinical and imaging features. Comparison was then made with a group of adults presenting during the same period.

Results: 28 paediatric patients were included (12 males and 16 females with mean age 11.2 years, range 3-18 years). Joints involved were the knee (n = 22; 78.6%), ankle (n = 4; 14.3%), hip (n = 1; 3.6%) and elbow (n = 1; 3.6%). Lesion morphology was Type 1 (n = 18; 64.3%), Type 2 (n = 3; 10.7%), Type 3 (n = 1; 3.6%) and Type 4 (n = 5; 17.9%). Final diagnosis was made by image-guided biopsy/resection in 18 (64.3%) patients. The commonest neoplastic lesion was tenosynovial giant cell tumour (n = 11; 39.3%), followed by synovial haemangioma (n = 5; 17.9%). There was only a single malignant lesion, a case of synovial sarcoma. Of eight (28.6%) non-neoplastic lesions, three were diagnosed as juvenile idiopathic arthritis and three as non-specific synovitis. There was no difference compared to adults regarding gender, joint involved or lesion morphology, but there was a significant difference in final diagnoses (p < 0.001). The range of intra-articular tumours and tumour-like lesions in children differs from that in adults, although tenosynovial giant cell tumour is the commonest diagnosis in both groups and malignant lesions are rare.

Advances in knowledgeart: In our series, ~16% of tumours and tumour-like lesions of joints occur in the paediatric population. Tenosynovial giant cell tumour remains the commonest diagnosis in children as in adults. Synovial haemangioma and juvenile idiopathic arthritis were the next commonest diagnoses in children, while primary synovial chondromatosis and reactive synovitis were the next commonest diagnoses in adults. Malignant lesions are rare in both groups.

Figure 1.

A 17-year-old female with anterior knee pain. (a) Sagittal PDW FSE and (b) axial SPAIR MR images demonstrate a mass (arrows) in the deep infra-patellar fat pad which contains a prominent area of low SI (arrowheads) suggestive of chronic haemorrhage. The features are consistent with a Type 1 lesion. The imaging diagnosis was localised tGCT, which was histologically confirmed.

Figure 2.

A 4-year-old boy with anterior ankle swelling. (a) Sagittal PDW FSE and (b) axial SPAIR MR images demonstrate a mass in the anterior joint recess (arrows) which is eroding the talar neck, consistent with a Type 1 lesion. The imaging diagnosis was localised tGCT, but histology confirmed a myofibroma.

Figure 3.

A 13-year-old girl with knee pain. (a) (b) Sagittal and (c) axial STIR MR images demonstrate multiple small masses (arrows) in the posterior joint recess and intercondylar notch consistent with a Type 2 lesion. Histologically confirmed multifocal localised tGCT.

Figure 4.

A 4-year-old boy with left knee swelling. (a) Sagittal and (b) axial STIR MR images demonstrate a lobular hyperintense mass extending throughout the joint (arrows) consistent with a Type 3 lesion. The imaging diagnosis was synovial haemangioma.

Figure 5.

A 14-year-old girl with right knee swelling. (a) Sagittal and (b) axial STIR MR images demonstrate a massive joint effusion (arrows) which contains widespread villous synovial thickening (black arrowheads) consistent with a Type 4 lesion. The imaging diagnosis was diffuse tGCT.

Figure 6.

An 11-year-old boy with right knee swelling. (a) Coronal T1W TSE, (b) sagittal T2W FSE and (c) axial STIR MR images demonstrate a serpentine, lobular mass in the anterior joint (arrows) consistent with a synovial haemangioma. The lesion also contains focal areas of low SI due to intra-vascular thrombi (arrowheads-c).

Figure 7.

An 8-year-old girl with left knee swelling. (a) Sagittal T1W TSE, (b) axial SPAIR and (c) sagittal fat suppressed post-contrast T1W TSE MR images demonstrate a lobular fluid SI mass in Hoffa’s fat pad which shows heterogeneous enhancement (arrows). The suggested imaging diagnosis was of a synovial chondroma, but biopsy confirmed a high-grade synovial sarcoma.

Figure 8.

A 9-year-old girl with a swollen painful left knee. (a) Sagittal T1W TSE, (b) sagittal STIR and (c) fat suppressed post-contrast T1W TSE MR images demonstrate enhancing thickened synovium in the supra patellar pouch, Hoffa’s fat pad and the semimembranosus-gastrocnemius bursa (arrows-a,b), with diffuse enhancement of the mildly thickened synovial lining (arrows-c). Note also an enlarged popliteal lymph node (arrowheads-a,b). An imaging diagnosis of juvenile idiopathic arthritis was made.

Figure 9.

A 15-year-old boy with left knee pain and swelling. (a) Sagittal T1W TSE and (b) axial SPAIR MR images demonstrate a mass in the supra patellar pouch (arrows). An imaging diagnosis of localised tGCT was made, but biopsy showed non-specific synovitis.