Morphological changes observed via fetal ultrasound in prenatally diagnosed and isolated congenital lymphangiomas: three case reports.

We illustrate three cases of isolated congenital lymphangioma (CL). Fetal ultrasound (US) demonstrated uniloculated cystic masses that changed to multiloculated, subcutaneous, hypoechoic, avascular cystic masses with thin septations without solid components. Case 1: CL of the right forearm; Case 2: CL of the right hypochondrium; and Case 3: CL of the left upper posterior back. Postnatal US detected multiloculated, subcutaneous, hypoechoic, avascular cystic masses with thin septations without solid components or invasive developments. We prenatally and postnatally diagnosed them as isolated CL cases due to focal, soft, bulging masses with unclear margins. Due to our correct diagnosis and precise evaluation of sizes and locations, no perinatal complications occurred. In this case series, uniloculated features changed to multiloculated features and the largest macrocyst size decreased, whereas the sizes of the smaller microcysts increased. These morphological changes observed via fetal US represent intermittent CL growing processes.