The potential histogenic relationship of the peripheral nerve to synovioma.

The belief that synoviomas differentiate from the synovial membrane has been widely accepted. Absolute proof is lacking, mainly because precancerous synovial atypia has not been documented in human tissue. During the last 50 years, pain has emerged as one of the significant features of synovioma, occurring very early in the course of the disease in some patients. Gross relationship to nerve, cumulative histological data, and theoretical relationships with three other cancers of neural origin suggest the nerve sheath as an alternate parent tissue for synovioma. Three cases illustrating nerve involvement are included.