Artyom Sidorkin, 28, went to a hospital in his hometown in central Russia last week complaining of chest pain.
Doctors x-rayed his chest and spotted what they thought was a tumor. When a surgeon performed a biopsy, however, a few tender green needles poked out.
Doctors think Sidorkin inhaled the seed and it somehow took root. They're preserving the surrounding lung tissue for further study.