Spinal pigmented villonodular synovitis and tenosynovial giant cell tumor: A report of two cases and a comprehensive systematic review.

ABSTRACT

BACKGROUND AND OBJECTIVE: Pigmented villonodular synovitis (PVNS) is a lesion of uncertain etiology that involves the synovial membranes of joints or tendon sheaths, representing a diffuse and non-encapsulated form of the more common giant cell tumors of the synovium (GCTTS). PVNS was reclassified to denote a diffuse form of synovial giant cell tumor (TSGCT), while 'giant cell tumor of the tendon sheath (GCTTS)' was used for localized lesions. These pathologies rarely affect the axial skeleton. We provide an unprecedented and extensive systematic review of both lesions highlighting presentation, diagnostic considerations, treatment, prognosis, and outcomes, and we report a short case-series. METHOD: We describe two-cases and conduct a systematic review in accordance with PRISMA guidelines. RESULT: PVNS was identified in most of the cases reviewed (91.6 %), manifesting predominantly in the cervical spine (40 %). Patients commonly presented with neck pain (59 %), back pain (53 %), and lower back pain (81.2 %) for cervical, thoracic, and lumbar lesions, respectively. GTR occurred at rates of 94 %, 80 %, and 87.5 %. Recurrence was most common in the lumbar region (30.7 %). GCTTS cases (8%) manifested in the cervical and thoracic spine at the same frequency. We reported first case of GCTTS in the lumbosacral region. Both poses high rate of facet and epidural involvements. CONCLUSION: Spinal PVNS and GCTTS are rare. These lesions manifest most commonly as PVNS within the cervical spine. Both types have a high rate of facet and epidural involvement, while PVNS has the highest rate of recurrence within the lumbar spine. The clinical and radiological features of these lesions make them difficult to differentiate from others with similar histogenesis, necessitating tissue diagnosis. Proper management via GTR resolves the lesion, with low rates of recurrence.