Keratinocyte carcinomas arising near arteriovenous fistulas: Case series and safety considerations for dermatologic surgery: A report of the International Transplant Skin Cancer Collaborative

Venous Free Flap with Interposition Bypass Graft for Arteriovenous Fistula Preservation: A Case Report

Cutaneous squamous cell carcinoma (CSCC) overlying an arteriovenous fistula (AVF) is rare and presents unique challenges. This case report describes a method of fistula preservation after CSCC excision using a flow-through venous free flap. The saphenous vein of the venous flap was used as flow-through segment for AVF preservation. The flap was inserted along the dorsal aspect of the forearm wound and microvascular anastomosis of the arterial inflow was completed using a vein just proximal to the radiocephalic fistula anastomosis. Venous outflow was established by creating an end-to-end vascular anastomosis between the cephalic vein and the greater saphenous vein. A separate subcutaneous vein was used to provide a low-pressure outflow for the flap to avoid congestion. This case demonstrates an option for AVF preservation that has not been previously described. It also highlights the importance of a multidisciplinary approach for the safe treatment of CSCCs overlying AVFs.

A Metastatic Well-differentiated Squamous Cell Carcinoma in a Patient with an Arteriovenous Fistula

Patients receiving hemodialysis have an increased risk of developing nonmelanoma skin cancers, such as cutaneous squamous cell carcinoma (SCC). Management of SCC usually relies on complete surgical excision of the primary tumor and may require regional lymph node dissection due to lymphatic spread. An 81-year-old man with an arteriovenous fistula (AVF) presented with an unusually aggressive metastatic well-differentiated SCC, necessitating an axillary dissection for lymph node metastasis. He had been referred for radiotherapy to complete his oncological treatment following excision of the primary SCC on his forearm. An AVF site is subjected to significant changes in circulatory pressure, leading to reduced lymphatic drainage and likely focal immunosuppression. Increased lymphatic burden, combined with repeated trauma to the fistula in an immunosuppressed patient, potentially precipitated the development of an SCC on the affected limb. The individual risk factors for SCC such as sites of chronic inflammation and repeated trauma, host immunosuppression, and renal disease are well established. This patient demonstrates the perfect storm of all these risk factors, leading to a highly malignant metastatic SCC. As the standards of renal care improve and the number of patients with AVF increases, we must remain vigilant in the management of SCCs in these patients.