Fabrice Cuillier, MD*; P. Lemaire, MD**; J. Bideault, MD***; Alice Bertha****.

*      Department of Gynecology, Félix Guyon Hospital, 97400 Saint-Denis, Réunion, France;
**     Sonographer, Echographic room, Moufia street, 97400 Saint-Denis, Réunion, France;
***    Department of Gynecology, Intercommunal Hospital, 97300 Saint-Benois, Réunion, France;
***** Student, Arizona State University. University Drive and Mill Avenue Tempe, Arizona 85281.

Abstract

We report four cases of fetal left subdiaphragmatic cysts diagnosed during ultrasound examination at 27th, 30th, and 32nd week of pregnancy. Serial ultrasound evaluation demonstrated no increase in size of the cysts during pregnancy. Anatomic site and ultrasonographic features of the lesions led us to the diagnosis of the splenic cysts. All four diagnoses were confirmed after the birth and were progressively decreasing in size until their complete regression a few months later.

Introduction

Gastrointestinal anomalies make up 15 to 20 % of fetal malformations [1, 2]. Prenatal finding of a cystic lesion of the spleen is rare, but possible, usually during the third trimester. Conversely, splenic cysts are commonly seen in late childhood [3]. Presence of the splenic cyst can result in some complications, such as their rupture and infection [3]. Splenic cysts found prenatally tend to disappear later in pregnancy or after birth [5].

We present four cases of splenic cysts found during ultrasound examination at 27th, 30th, and 32nd week of pregnancy and followed up subsequently. Series of prenatal ultrasonographic examinations as well as the postnatal investigation confirmed the diagnoses.

Case reports

Case number 1

A 29-year-old woman, G3P2 presented at 27 week of pregnancy. Her first trimester ultrasound and triple test were normal. The 27th week transabdominal sonography showed a round unilocular cystic lesion in the left anterior abdominal quadrant, beneath the stomach (Figure 1). No other anomalies were detected. The amount of amniotic fluid was normal. Based on its location and appearance, the diagnosis of splenic cyst was considered. A multidisciplinary consultation led us to conservative management with ultrasonographic follow without an amniocentesis. At 30 weeks a MRI was done (Figures 2, 3). The patient delivered at 37 weeks (fetal weight 4000 grams). Postnatal clinical examination of the neonate was normal. Neonatal abdominal ultrasound confirmed the splenic cyst of 5 mm in size. No other anomalies were seen. Three months after delivery the cyst has disappeared (Figure 4).

Figures 1, 2. Figure 1: 27th week of pregnancy; transverse scan through the fetal upper abdomen showing an intraabdominal cyst in the splenic region. Figure 2: 30 weeks of pregnancy; T2-weighted coronal magnetic resonance image showing a cystic lesion in the upper left quadrant of the fetal abdomen.

Figures 3, 4. Figure 3: 30 weeks of pregnancy; T2-weighted transverse magnetic resonance image of the abdomen showing a cystic lesion in the upper left quadrant of the fetal abdomen. Figure 4: Postnatal sonography of the spleen showing the cyst.

Case number 2

A 25 year-old patient with normal first and second trimester ultrasonography and normal triple test presented at 32 weeks of pregnancy. A cystic structure was identified in left upper abdominal quadrant of the fetus (Figures 5, 6). Repeated examination at 37 weeks confirmed the finding (Figure 7). The pregnancy terminated by spontaneous vaginal delivery at 39 weeks. Postnatal ultrasonography of the neonate confirmed the cystic lesion located in the spleen. Repeated exam two months after delivery found normal spleen without any cystic structure.

Figures 5, 6. 33 weeks of pregnancy; Figure 5: Color Doppler transverse scan through the upper abdomen showing a cystic structure within the spleen. Figure 6: Left parasagittal abdominal view showing a cystic structure within the spleen.

Figure 7. Transverse color Doppler sonography of the upper abdomen at 37 weeks showing an intrasplenic cystic structure.

Case number 3

A 30 year-old patient, with normal first and second trimester ultrasonographic screening and with normal triple test, presented to our unit at 30 weeks of pregnancy. A cystic structure in the left upper abdomen of the fetus was identified (Figure 8) and confirmed by consequent ultrasonographic examination at 36 weeks (Figure 9). The pregnancy ended by spontaneous delivery at 38 weeks. Postnatal sonography confirmed the presence of the cystic lesion within the spleen. Three months later the cyst disappeared.

Figures 8, 9. 30 weeks of pregnancy; transverse (Image 8) and left parasagittal (Image 9) view of the fetal abdomen. A cystic structure is present within the spleen.

Case number 4

A 24 year-old patient with normal first and second trimester ultrasonography and normal triple test presented to our unit at 33 weeks of pregnancy. A cystic structure of in the splenic region was identified (Figure 10, 11). After spontaneous delivery, at 38 weeks, the ultrasonography confirmed the presence of the cystic lesion within the spleen. Three months later the cyst completely disappeared.

Figures 10, 11. 33 weeks of pregnancy; 30 weeks of pregnancy; transverse (Image 10) and left parasagittal (Image 11) view of the fetal abdomen. A cystic structure is present within the spleen.

Discussion

The fetal spleen develops during the 6th and 7th weeks from the aggregated reticular mesenchymal cells in the dorsal mesentery of the stomach. The fetal spleen contributes only to the production of the fetal megakaryocytes and thrombopoiesis.

Cystic lesions of the spleen occasionally develop within the spleen. The nonparasitic cysts are uncommon and of varying etiology. Postnatally the lesions are classified as true (primary) or false (secondary) cysts.

• The False cysts or pseudocysts have a fibrous capsule and may be post-traumatic, inflammatory or degenerative.
• The true splenic cysts, with a cellular layer, include vascular, serous, infectious, and congenital cysts and neoplasms (epidermoid, dermoid, hemangioma and lymphangioma). They usually have good prognosis [2].

Nevertheless 25 % of the splenic cysts are of unknown etiology [3].

The majority of splenic cysts are benign. They are not associated with fetal or infant compromise. Some cysts, however, can enlarge and can become symptomatic with a risk of post-traumatic rupture, hemorrhage and infection [3].

Prenatally the fetal spleen can be identified by ultrasound, and therefore cysts of the adjacent organs can be excluded. These lesions are usually diagnosed during the third trimester. Fetal spleen can be visualized by ultrasound from about 20 weeks of gestation. Okada and al report a case of splenic cyst observed as early as at 17 weeks of pregnancy. Yilmazer and Erden [5] described one case of the splenic cyst discovered at 31 weeks, which disappeared after seven months. Kabbra et al [7] described prenatal finding of the splenic cyst at 20 weeks of pregnancy.

Differential diagnosis

Several diagnoses may be considered when a cystic structure in the left upper abdomen of the fetus is found [8-10]:

Gastrointestinal cysts, such as choledochal and mesenteric cysts are preferentially located in the right and anterior part of the abdomen. The absence of septations can distinguish splenic cysts from duplication cysts. Renal cysts can be differentiated from splenic cysts by their topography related to the kidneys. Renal cystic dysplasia, hydronephrosis or obstructed duplication can be easily eliminated. Adrenal tumors may be cystic, but in this case they are heterogeneous in appearance. Ovarian cysts, pancreatic pseudocysts and mesenteric cysts are very rare. Omental cysts, choledochal cysts and left hepatic cysts are also very rare.

Management

Expectational management and surveillance can be recommended when a splenic cyst is found.

Garel at al [10] described seven cases of small, asymptomatic splenic cyst-like lesions diagnosed in fetuses and neonates [6-7]. None of these cysts were operated. Three of them completely disappeared. 

Toddle at al [6] reported a case of prenatal diagnosis of the large left upper quadrant mass that was apparent at ultrasound at 32 weeks. Laparotomy was done at third day of life and a large splenic cyst (7 cm) was found in the lower pole of the spleen. Partial splenectomy was performed and no other cysts were found in other organs.

Conclusions

Published data and our experience indicate that an expectational management and surveillance can be recommended in the case of fetal splenic cysts. The vast majority of congenital splenic cysts disappear spontaneously during the first three month of life.

References

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