Histopathological and immunohistochemical investigation of primary avalvular varicose anomalies (PAVA) in a patient with primary varicose veins and PAVA

Background:Primary avalvular varicose anomalies (PAVA) are found in 4.6% patients with primary varicose veins and can be confused with neovascular tissue. These veins can be found in all compartments of the leg and are found more commonly in patients with pelvic venous reflux. Little is known about these atypical vessels and so we are reporting the histopathologic features of PAVA compared to a typical varicosity.Methods:A section of PAVA was removed under ultrasound guidance from a patient undergoing routine endovenous thermoablation for varicose veins, along with several varicosities extracted by phlebectomy. Venous tissue was fixed in buffered formalin and underwent routine histological processing into paraffin wax. Sections were cut 4 microns thick and were stained with haematoxylin and eosin (H&E), Martius Scarlett Blue (MSB) and immunohistochemical staining for smooth muscle actin (SMA). Stained sections were examined by a board-certified pathologist.Results:PAVA showed distinct differences from “normal” varicose veins. There were multiple protrusions into the lumen of the abnormal vessel, due to an irregularly enlarged media. The media was rich in collagen and there was a reduction in the smooth muscle cells found circumferentially throughout the media and adventitia. Varicosities removed by phlebectomy appeared normal, with all three tunicae clearly visible. Conclusions:Although the samples only came from one patient, they showed clear differences histologically PAVA and “normal” varicose venous tissue. This early report needs to be confirmed in a larger sample of patients and more work is needed to understand the exact derivation of PAVA.