PIGMENTED VILLONODULAR SYNOVITIS (PVNS): A DIAGNOSTIC AND THERAPEUTIC CHALLENGE: CASE SERIES

Abstract

Introduction: PVNS is a benign proliferative disorder of the synovium presenting as local or diffuse variants. The condition commonly involves the knee with a slow and indolent progress.

Case series:

1. Presented with anterior knee pain. Examination revealed supra-patellar fullness and tenderness. MRI scan showed a suspicious soft tissue tumour. Histology confirmed PVNS after excision biopsy.

2. Presented with medial knee pain, most pronounced after exercise. McMurray test was positive for a meniscal tear. MRI confirmed meniscal tear and additional localised PVNS. The patient underwent repair of the meniscal injury but continued to complain of pain. Following excision of PVNS there was marked improvement in the patients’ symptoms.

3. Presented as massive soft tissue swelling of the right knee. Past medical history included a diagnosis of tuberculosis and fibrosarcoma on the knee. She was referred to our centre following two diagnoses, three surgeries and a supracondylar femoral fracture. The patient was previously advised an above knee amputation which she refused. A repeat biopsy with immunohistochemistry studies at our unit confirmed the diagnosis of a PVNS. Patient is awaiting a total knee replacement with subtotal synovectomy.

4. Presented with swollen right knee, pain and restriction of movement. MRI scan suggested a diagnosis of PVNS. The patient underwent subtotal synovectomy and histology confirmed this to be PVNS. Subsequently the patient had two recurrences, the first at 2 years and later at 4 years from initial surgery. Repeat MRI scan showed extensive third recurrence. The patient is awaiting a further open synovectomy, followed by low dose radiotherapy.

Conclusion: This case series aims to highlight the complexities in diagnosing PVNS. It should be a differential diagnosis of any kind of soft tissue problem especially around the knee. Immunohistochemistry may be useful. Multiple recurrences is a problem; adjuvant therapy may be indicated in resistant cases.