Microcystic congenital cystic adenomatoid malformations (CCAM), when associated with hydrops, carry a dismal prognosis. Options for treatment are limited and experimental, including antenatal corticosteroids, open fetal surgery, laser ablation and, more recently, sclerotherapy. We describe a case of a large, predominantly microcystic CCAM in a hydropic fetus treated successfully with direct interstitial injection of a sclerosant agent (3% sodium tetradecyl sulfate) at 23⁺³ weeks gestation, after multiple failed courses of steroids. Elective thoracoscopic right lower lobectomy was performed at 1 year of life and there have been no respiratory or other medical morbidities since. A literature review of fetal lung masses treated with sclerosants antenatally reveals that sclerotherapy may represent a novel treatment option for large hydropic microcystic CCAMs, which are unresponsive to corticosteroids. Further studies are required to evaluate the utility and safety of fetal sclerotherapy, as this may represent an alternative minimally invasive treatment option to fetal lobectomy.