PIGMENTED VILLONODULAR SYNOVITIS OF THE FOOT AND ANKLE

Abstract

Fourteen cases of pigmented villonodular synovitis (PVNS) of the foot and ankle (between January 1957 and December 1999) accrued from Scottish bone tumor registry are presented with an average follow-up of 4.6 years aimed to analyse the clinical, radiological and histopathological features in order to investigate the clinical behaviour of PVNS in the foot and ankle, and to determine the factors influencing recurrence. The mean age was 26.4 years (range, 8 to 52 years). There were eight females and six males. The mean delay in presentation was 10.3 months. The anatomical sites were foot phalanges (n=2), tarso-metatarsal area (n=3) and hindfoot (n=9). Hindfoot cases comprised of 6 extra-articular soft tissue swelling around the ankle, two affecting the ankle joint and one involving the subtalar joint. There were eight (57.1%) cases presented with painless lump, five (35.7%) patients with painful lumps and one case with a lump associated with toe deformity. The clinical suspicion were ganglion, gout, soft tissue swelling (? tumour) and exostosis. Peri-articular tissue invasion and cortical infiltration was found in one third on plain films. CT scan showed multiple lytic lesions and MRI scan findings were consistent with extensive low signal soft tissue hypertrophy and bone erosion, two of which were suspected with synovial sarcoma. Excision of the lump was done in 4 cases with a complete recovery. Foot phalangeal PVNS were treated with toe amputation through metatarsophalangeal joint and no cases had recurrence of the lesion. There were two recurrences affecting the ankle and the subtalar joint. Recurrent ankle PVNS was treated with re-exploration, open synovectomy, curettage of talar cyst and autogenous bone grafting. The second recurrent case involving subtalar joint was treated with re-excision and curettage. Both recurred cases were primarily treated with intralesional excision for their diffuse variety. There were no recurrences in the nodular variety. Complete recovery was achieved in 85.7% case (12/14). A high index of suspicion for PVNS should be observed for cases presenting with a painless or painful mass in the foot and ankle region. Complete recovery can be achieved in the majority by complete excision. Toe amputation may be considered for foot phalangeal PVNS.