diff --git a/src/Microsoft.OpenApi/Models/OpenApiOperation.cs b/src/Microsoft.OpenApi/Models/OpenApiOperation.cs
index ba0af7317..7983a243e 100644
--- a/src/Microsoft.OpenApi/Models/OpenApiOperation.cs
+++ b/src/Microsoft.OpenApi/Models/OpenApiOperation.cs
@@ -253,9 +253,11 @@ public void SerializeAsV2(IOpenApiWriter writer)
                 {
                     foreach (var property in RequestBody.Content.First().Value.Schema.Properties)
                     {
-                        var paramName = property.Key;
                         var paramSchema = property.Value;
-                        if (paramSchema.Type == "string" && paramSchema.Format == "binary") {
+                        if ("string".Equals(paramSchema.Type, StringComparison.OrdinalIgnoreCase) 
+                            && ("binary".Equals(paramSchema.Format, StringComparison.OrdinalIgnoreCase) 
+                            || "base64".Equals(paramSchema.Format, StringComparison.OrdinalIgnoreCase)))
+                        {
                             paramSchema.Type = "file";
                             paramSchema.Format = null;
                         }