Back To The Course

Abdominal Cysts

Sonographic differential diagnosis of abdominal cyst is often necessary to obtain the following critical information to narrow the diagnosis:

Fig 1, Fig 2, Fig 3, Fig 4, Fig 5, Fig 6, Fig 7, Fig 8, Fig 9

  •  Location
    • close to the spine: usually related to renal abnormalities, etc.
    • right upper quadrant: typically hepatic cyst or choledochal cyst
    • close to the umbilicus: mesenteric cyst, umbilical vein varix, meconium pseudocyst, ovarian cyst
    • lower abdomen: urachal cyst, ovarian cyst, hydrometrocolpos, megacystis
  • Size and shape of the lesion
    • unilocular, round: ovarian cyst
    • multiple loops: bowel obstruction
    • tubular: dilated ureter
  • Fetal gender
    • always female: ovarian cyst, hydrometrocolpos
    • usually female: hepatic cyst, choledochal cyst
    • usually male: bladder outlet obstruction, ureterocele, hydronephrosis
  • The change in appearance over time
    • dilated bowel
    • partial obstruction of the urinary tract
  • Other information is often helpful: the wall and contents of the cyst, the relationship to other abdominal organs, peristalsis activity, etc.

Fig 1:  Fetal dermoid cyst  Cross-section at the upper abdomen: cystic mass (*) containing echogenic debris or sebum (arrowhead = spine, circle = liver)

Fig 2:  Fetal ovarian cyst  Cross-section of the fetal upper abdomen: simple anechoic cyst (*) (arrowhead = spine)

Fig 3:  Fetal ovarian cyst  Cross-sectional scan of the abdomen: Simple anechoic cyst (*) in the rightside of the abdomen, note normal kidney and adrenal gland (arrowhead)

Fig 4:  Large urachal cyst  Sagittal scan of the fetal trunk: large cystic mass (*) connecting with the bladder, externally protruding from the lower abdomen

Fig 5:  Large umbilical vein aneurysm  Cross-sectional scan of the abdomen: cystic mass (solid circle) connecting with umbilical vein (arrow) with Doppler signal on flow study (* = stomach, arrowhead = spine)

Fig 6:  Choledocal duct cyst  Coronal scan of the abdomen: anechoic cystic mass (*) located at the right upper abdomen with pressure effect on the liver (arrowhead = renal cystic dysplasia)

Fig 7:  Duodenal atresia  Cross-sectional scan of the abdomen: Double bubble sign: two cystic masses (* = proximal duodenum, solid circle = stomach) in the upper abdomen

Fig 8:  Proximal jejunal atresia  Cross-sectional scan of the abdomen: marked dilatation of the bowel loop with continuation of stomach (solid circle), duodenum (*) and proximal jejunal

Fig 9:  Small bowel obstruction  Cross-sectional scan of the abdomen: Multiple loop of small bowel loops with marked dilatation (*)

Video clips of abdominal cysts

Hepatic cyst:  Isolated cystic mass located at right upper abdomen

Bladder outlet obstruction:  Coronal scan: Megacystis (C) at 11 weeks of gestation (H = head)

Renal cysts:  Multicystic kidney and marked hydronephrosis of the contralateral kidney

Bowel duplication:  Sausage cystic mass secondary to bowel duplication; isolated bowel loop with no other visible bowel loops

Duodenal atrestia:  Double bubble sign with continuation representing stomach (St) and duodenum (D) (Sp = spine)

Proximal jejunal atresia:  Dilated bowel loop at the upper abdomen representing the proximal jejunal loop separated from the stomach and large bowel

Renal cystic dysplasia:  Cross-sectional scan of the abdomen: muliticystic kidney (*) with oligohydramnios and absent contralateral kidney

The main sonographic differential diagnoses include

Choledochal cyst/hepatic cyst:

  • anechoic single cyst in liver, choledochal cyst located adjacent to hepatic ducts
  • more common in females
  • not associated with other anomalies

Multicystic kidneys:

  • anechoic multicysts of variable size which are non-communicating
  • located posteriorly
  • unilateral or bilateral
  • male or female

Hydronephrosis:

  • anechoic single or often multiple communicating cysts within renal fossa
  • more common in males
  • probably associated with other GU anomalies

Hydroureter:

  • anechoic tubular cyst in nature
  • communicating with renal pelvis and bladder
  • located posteriorly
  • more common in males
  • may be associated with megacystis

Meconium pseudocyst:

  • echogenic cyst with calcified wall at mid-abdomen
  • associated with bowel obstruction
  • male or female

Mesenteric/omental cyst:

  • isolated anechoic cyst, unilocular or less commonly septated
  • often mobile
  • located centrally
  • male or female

Urachal cyst:

  • isolated anechoic simple
  • communicates with the bladder and also commonly with the umbilicus
  • located anteriorly
  • male or female

Ovarian cyst:

  • isolated unilocular, sometimes septated, or daughter cyst
  • usually unilateral
  • located lower or laterally
  • only in females

Duodenal atresia:

  • double bubble sign in upper abdomen
  • connection between the two bubbles
  • polyhydramnios
  • male or female
  • commonly related to trisomy 21

Small bowel obstruction:

  • multiple bowel loops with echogenic contents
  • tubular in nature
  • located centrally or throughout the abdomen
  • peristalsis
  • male or female

Hydrometrocolpos:

  • anechoic to echogenic cyst
  • located retrovesically
  • only in females