Paediatric radiologyCase Type
Anca Oprisan, Roberto Llorens-Salvador, Marialaura Mena-Cavelis, Vicente Belloch-Ripolles, Eduardo Baettig-Arriagada, Ali Boukhoubza, Amparo Moreno-FloresPatient
37 years, female
A 37-year-old pregnant woman was submitted to our Hospital due to threatened preterm labour at 31 weeks of gestation. Obstetrical ultrasound (US) was performed. Severe polyhydramnios and dilated fetal abdominal cavity with multiple cysts were identified. The mother refused fetal intervention or prenatal invasive tests. Caesarean section was performed.
Transabdominal fetal US could be performed prior to delivery, showing polyhydramnios and complex multiseptated fetal ascites (Fig.1). Postnatally, anteroposterior portable X-ray was performed in the NICU, and showed remarkable abdominal distension and central cranially displaced small bowel loops. No calcifications were seen. (Fig.2). Neonatal abdominal US confirmed occupation of the entire abdominal cavity by multiple cysts of different sizes, with different levels of echogenicity, from anechoic to some with echogenic content and fluid-fluid levels with signs of bleeding (Figs.3). Liver and spleen were cranially displaced. The kidneys were normal. The abdominal aorta and inferior cava were compressed but patent.
Lymphatic malformations (LM), formerly known as lymphangiomas, are slow-flow vascular malformations of the lymphatic system, characterized by anastomosed lymphatic channels with the venous system during the fetal period. These abnormal connections result in numerous varying size cystic spaces  .
Over half of the cases presents at birth, and the rest of them occur during the first two years of life. Congenital LM is more often seen in the neck area, axillary region or even the mediastinum, and occurs less often in the intraabdominal visceral organs, affecting the mesentery, omentum and retroperitoneal space at a rate of less than 1% .
They are characteristically slow-growing lesions, with unspecific symptoms like nausea, abdominal pain or distension. Because of the variation in size and location they can remain asymptomatic for a lifetime or can produce life-threatening complications. While small intraabdominal LM causes only accumulation of a small volume of fluid, symptoms can occur if the mass increases in size . They can also reach alarming sizes due to rapid massive growth and present as acute abdominal conditions, such as intraabdominal bleeding, volvulus or intestinal obstruction, as in this case [5-7]. Nevertheless, over time LM does not demonstrate malignant degeneration .
US is highly sensitive for diagnosing abdominal LM and is the imaging modality of choice for follow-up although Magnetic Resonance imaging can be useful to evaluate LM extension or complications . Mesenteric LM can be macro and/or microcystic, presenting as multicystic masses with thin internal septations. When haemorrhage or infection occur in LM fluid-fluid levels of different echogenicities and thicker septa are commonly present. The progression of these lesions can occur up to 10-years after diagnosis, but it is most likely to occur within the first year .
These cystic lesions can mimic renal cysts, meconium pseudocyst, intestinal atresia or ascites. In case of renal cysts, the diagnosis by US could be established by continuing the cysts with the renal parenchyma. If there is a distal ileal atresia the X-ray and the US should help identify the proximal dilatation. And in case of a meconium pseudocyst in US is seen as a hypoechogenic mass surrounded by an echogenic calcified wall.
The treatment of choice for mesenteric LM is surgical resection. Up to 60% of patients require small bowel resection, with a very low rate of recurrence and mortality .
Written informed patient consent for publication has been obtained.
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