Based on 8 personal cases and a 81-cases review of literature, it's authors' opinion that cystic or solid masses issued form posterior lumbar articular process and called according to the cases synovial cyst, ganglion cyst, benign synovialoma, pigmented villonodular synovitis, are a single variety of benign degeneration of soft articular tissues. The cystic or solid feature of these masses depends upon the extent of their histiocytic granulomatous proliferation. They may be asymptomatic, accompany chronic lumbar pain or cause sciatica, seldom cauda equina syndrome. In case of sciatica, clinical picture rather consists of a narrow lateral recess than a discal protrusion. CT scan is the best investigation to get a right preoperative diagnosis. Postoperative prognosis is excellent and no anatomical recurrence has been reported.