Malpractice risk in the outpatient setting is significant and claims often involve missed and delayed diagnoses. This retrospective study examined diagnostic error claims in outpatient general medicine to identify characteristics and causes of cancer misdiagnoses. Similar to a prior study, investigators found that missed cancer diagnosis is the leading type of diagnostic error in primary care, constituting nearly half of closed diagnostic claims. Contributing factors included failure or delay in test ordering or consultation. These findings suggest that improving test results management and consultative processes may reduce malpractice risk related to outpatient diagnosis. A previous WebM&M commentary discussed an incident involving a missed diagnosis of spinal cord injury in primary care.