Malignant Pigmented Villonodular Synovitis-A Rare Entity

INTRODUCTION: Malignant pigmented villonodular synovitis (PVNS) or Malignant giant cell tumour tendon sheath (MGCTTS) is a controversial and debatable lesion. Few case reports have indicated the potential for metastasis.1These aggressive cases are designated malignant giant cell tumour tendon sheath or malignant PVNS. Less than 20 cases are described in literature. We report a case of 65 year old lady who was diagnosed eight years back as pigmented villonodular synovitis. She had multiple local recurrences and now presented with lymphnodal metastases, which is extremely rare. CASE REPORT: Sixty five year old lady presented with swelling in left inguinal region of six months duration. She gave a past history of swelling around medial condyle of left femur eight years back. Swelling was excised three times. At the time of third recurrence, swelling was extensive, infiltrating surrounding tissues and underlying bone, encasing femoral and popliteal vessels for which she underwent an above knee amputation. She now presented with inguinal swelling measuring 5.7×3.0 cms. Positron Emission Tomography Scan (PET-CT) revealed multiple enlarged left common iliac, internal and external iliac nodes, largest measuring 7.0 cms. Both the inguinal and pelvic nodes were excised. Lesion was diagnosed as metastatic deposits of Malignant pigmented villonodular synovitis based on morphological and Immunohistochemical findings. CONCLUSION: It is important to have a high index of clinical suspicion because these lesions can have an aggressive behaviour even with bland cytological features. Our experience suggests that in a recurrent lesion for GCTTS. A wide surgical excision with safe surgical margins and close follow up with radiological evaluation might help to diagnose these lesions early and be amenable to limb salvage surgeries.