We report the rare occurrence of a progressive fetal axillary cystic lymphangioma coexistent with an overlying naevus flammeus. The fetus at 22 weeks' gestation was found to have a 37 x 35 mm left axillary multiloculated mass without colour-flow imaging. Amniocentesis showed a normal 46,XX karyotype. Multiple fine-needle aspirations of the mass in the second and third trimesters obtained blood-stained chocolate-coloured fluid containing numerous erythrocytes and lymphocytes but proved ineffective in lessening the progressive growth of the mass. The mother underwent caesarean delivery and a healthy neonate was born with a 141 x 81 mm left axillary cystic lymphangioma and a 50 x 35 mm coexistent naevus flammeus. The neonate was well after simple excision of the lesions. Although cystic lymphangiomas arising in the axilla enlarge progressively during fetal life, our case suggests a good prognosis and except for genetic evaluation, no prenatal intervention is required.