UNCOMMON PRESENTATION OF BILATERAL PIGMENTED VILLONODULAR SYNOVITIS ABSTRACT ID : IRIA 1149

BACKGROUND Pigmented Villonodular Synovitis (PVNS)- Benign proliferative disorder that affects synovial lined joints, bursae, and tendon sheaths . PVNS is a slow-growing lesion of uncertain etiology arising from the synovial membrane Two primary forms – a) Diffuse form affects the entire synovial lining of a joint, bursa or tendon sheath, involves the large joints. B)Localized form - occurs around the tendon sheaths of small joints.

Common presentation in 3rd to 4th decade. The disease may show extraarticular soft tissue involvement, along with a primary intraarticular process. PVNS involving the shoulder joint is uncommon and bilateral involvement of shoulder is < 1 % cases. Common presentation in 3rd to 4th decade. It is usually monoarticular, polyarticular involvement is rare. Commonly involved joints- knee/ ankle/ hip/ finger joints. Shoulder joint involvement is extremely rare.

Localized - Most common and involves small joints of the hand/feet. Two types: Diffuse - Affects the entire synovial lining of the joint, bursa, or tendon, involves the large joints such as the knee and hip joints. Localized - Most common and involves small joints of the hand/feet. The extra-articular form of PVNS is very rare and often represents an extension of a primary intra-articular process. CLINICAL FEATURES: --Pain of long duration/ Decreased range of motion/ Joint locking/ swelling of joint. --Extra articular present with soft-tissue mass. --Slight female predominance seen.

ETIOLOGY: --Inflammatory process --Repeated hemorrhage into the joint --Repetitive mild trauma --Neoplasia --Disorder of lipid metabolism --Genetic rearrangement in both localized and diffuse types of PVNS : chromosome 1p11-13, a site for CSF-1 gene, which most commonly fuses to COL6a3 on chromosome 2q35.

CASE REPORTS A 41 yr old female came with complaints of – Pain and swelling in both shoulders for past 5 months. Shoulder joint movement restriction since 5 months. Past history- No history of trauma. Not a known case of Tuberculosis/ Hypertension/ Diabetes mellitus. Previous CT imaging was done but images were not available. Family history- Not significant

EXAMINATION GENERAL EXAMINATION: - Afebrile, vitals stable SYSTEMIC EXAMINATION: OTHER SYSTEMS- RS/ CVS/ CNS – No abnormality detected. P/A- Soft. LOCAL EXAMINATION: -Inspection : Bilateral shoulder joint mild swelling. Shoulder joint movement was restricted. -Palpation: Bilateral warmth with tenderness present. Bilateral shoulder joint soft – firm mobile masses . Measurement- 5 x 4cm in right shoulder. 10 x 8cm in left shoulder. CLINICAL DIAGNOSIS: ? Tubercular villonodular synovitis.

IMAGING PLAIN RADIOGRAPH of both the shoulder joints showing homogenous soft tissue opacity infiltrating around the humerus.

ULTRASOUND of both shoulder showing markedly thickened hypo echoic synovium with nodular and villous projections with multiple heterogeneous echogenic masses

RT T1W Cor RT T2W Cor RT PDW Cor Gross distension of the sub acromial  sub deltoid bursa (red arrows) which is filled with fluid and a large extra articular multilobulated heterogeneous signal intensity lesion appearing low to intermediate signal intensity in T1w images (green arrows) with variable signal intensity in T2w images (yellow arrows) within it, superior to supraspinatus.

Post contrast, the lesion shows intense contrast enhancement. RT T2 FFE Cor RT T1c + Gd Cor T2 FFE sequence showing few blooming artefacts (yellow arrow) signifying hemosiderin. Post contrast, the lesion shows intense contrast enhancement.

RT PDW Axial RT T1c + Gd Cor PDW sequence showing few similar signal intensity lesions in the intra-articular region (yellow arrows) and supraspinatus muscle. Few bony lesions also noted (green arrow). Post contrast sequence showing similar enhancement pattern as the extra-articular component.

MRI PDW axial sequence showing few subchondral cystic changes in the head of humerus (yellow arrow). Few lesions showing similar signal intensity and enhancement pattern also seen in left head of humerus.

DIAGNOSIS Enhancing proliferative synovium with a lobulated mass in the subacromial subdeltoid bursa Erosions in the humeral head with minimal involvement of the shoulder joint and subscapularis muscle Features suggestive of extraarticular and intra articular form of diffuse type of pigmented villonodular synovitis

DIFFERENTIAL DIAGNOSIS Primary synovial chondromatosis --T2: high signal --loose bodies formation Lipoma arborescens --T2: high signal; will saturate on fat suppressed sequences Synovial sarcoma --Mass around, but outside of, joint --Frequently calcify Degenerative arthritis --Joint space narrowing --Subchondral sclerosis

CONCLUSION PVNS involvement of the shoulder joint is a rare location with bilateral joints involved is uncommon. Findings of both intraarticular and extraarticular involvement is a rare presentation The radiologic appearances of intraarticular PVNS, particularly its MR imaging findings, are frequently pathognomonic. MR imaging is the optimal modality to depict and define the intraarticular and, particularly, extraarticular disease extent in order to guide complete surgical excision

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