Macrocephaly-cutis marmorata telangiectatica congenita was first identified as a distinct syndrome in 1997. Since then there have been more than 10 further reports of the condition, several also comprising reviews of the earlier literature. Virtually all reported patients, however, are young children, and there is very little information about the natural evolution of the condition in adolescence and later life. This report describes a patient with features of macrocephaly-cutis marmorata telangiectatica congenita, though mildly affected, and her progression into teenage life. Her mild problems, many of which have largely resolved, demonstrate a possible more optimistic view of the condition than is currently held. The difficulties in making the diagnosis in an adult patient are also discussed.