ADVENTITIAL CYSTIC-DISEASE - A UNIFYING HYPOTHESIS

Purpose: Six cases of adventitial cystic disease were studied, and the existing theories of the aetiology of adventitial cystic disease were reviewed to present evidence in support of a variation of the develop mental hypothesis that might explain the sites of occurrence of this r are condition. Methods: Cases of adventitial cystic disease were colle cted by interrogation of the records of a group of vascular surgeons i n the Johannesburg area. After reviewing the relevant literature, the sites of occurrence of 323 cases of adventitial cystic disease were do cumented, and the theories of the formation of adventitial cystic dise ase were reviewed. The embryological origin of those vessels in which adventitial cystic disease occurs was investigated. Clinical cases wer e collected in private practice vascular referral centers. The clinica l features, treatment, and subsequent course of six cases of adventiti al cystic disease (four related to the popliteal artery, one in the fe moral artery, and one in the radial artery) are included. Results: All cases of adventitial cystic disease reported have occurred in the non axial arteries, which form at a later stage than the axial vessels dur ing limb differentiation and development. It is therefore postulated t hat during limb bud development cell rests derived from condensations of mesenchymal tissue destined to form the knee, hip, wrist, or ankle joints are incorporated into the nearby and adjacent nonaxial vessels during development of these vessels in the 15-22-week stage. These new ly forming nonaxial vessels develop from vascular plexuses during the same stage of development, and in close proximity to the adjacent cond ensing joint structures. It is further postulated that these cell rest s are then responsible for the formation of adventitial cystic disease later in Life, when the mucoid material secreted results in a mass le sion within the arterial or venous wall. Conclusion: There is evidence supporting the hypothesis that adventitial cystic disease is a develo pmental condition occurring in the nonaxial blood vessels.