diff --git a/src/pipdeptree/_discovery.py b/src/pipdeptree/_discovery.py
index 5507b61..09e290c 100644
--- a/src/pipdeptree/_discovery.py
+++ b/src/pipdeptree/_discovery.py
@@ -93,7 +93,7 @@ def filter_valid_distributions(iterable_dists: Iterable[Distribution]) -> list[D
 
 
 def has_valid_metadata(dist: Distribution) -> bool:
-    return dist.metadata["Name"] is not None
+    return "Name" in dist.metadata
 
 
 def render_invalid_metadata_text(site_dirs_with_invalid_metadata: set[str]) -> None: