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GIANT CYSTIC MECONIUM PERITONITIS

AJITA J NAWALE*, PARITOSH C KHANNA**, NOOR ANSARI**,SHYAMSUNDER R KOTEYAR*, ARVIND TIWARI**,KISHOR RAJPAL*, SULEMAN A MERCHANT***
*Lecturer; **Resident; ***Professor and Head, Department of Radiology and Imaging, LTM General Hospital and LTM Medical College, Sion, Mumbai.

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A case of giant cystic meconium peritonitis (type II meconium peritonitis) was diagnosed sonographically, in a 19 year old primigravida at 32 weeks of gestation. Based on the clinical features and sonographic findings of dilated small bowel loops, a large cyst with echogenic contents, intracystic calcification, marked polyhydramnios, a diagnosis of giant cystic meconium peritonitis was arrived at. These findings were confirmed postnatally.

CASE REPORT

A case of giant meconium pseudocyst secondary to rupture from intestinal obstruction, diagnosed by in utero sonography is presented.

In our case, a 19 year old primigravida, obstetric examination revealed that the uterus was tense, larger than the expected period of gestation, which by ultrasound, was determined to be approximately 32 weeks. Ultrasound also showed a marked degree of polyhydramnios. Ultrasound demonstrated a cystic abdominal mass with well-circumscribed echogenic walls, filled with echogenic viscid contents (Fig. 1) and a solitary echogenic focus (Fig. 2) with posterior acoustic shadowing within. In our case, the presence of dilated loops in the mid-abdomen pointed toward small bowel obstruction. The hepatobiliary system, adrenals and kidneys were normal. The most likely diagnosis was a meconium pseudocyst secondary to an in utero bowel rupture. The neonate, a male, was stillborn. Postnatal ultrasound (Fig. 2) confirmed the presence of the cystic lesion.

Fig. 1: Antenatal USG. Giant cyst showing a well circumscribed wall with thick, viscid echogenic material within.	Fig. 2: Postnatal USG. Cyst showing a calcific focus.

DISCUSSION

Meconium peritonitis is a sterile chemical peritonitis secondary to passage of meconium into the peritoneum, after gut perforation, and occurs in one of 30,000 live births.[1,2] An abdominal meconium pseudocyst results when the perforation occurs in utero but remains open allowing communication with the cystic cavity. The latter often is a large meconium filled cyst lined by a thick membrane, containing multiple calcium deposits and plaques.[1] Meconium peritonitis is characterized by intraperitoneal calcification, profuse fibrosis with or without pseudocyst formation due to the antenatal extravasation of meconium.

The types of meconium peritonitis include the fibro-adhesive type (type I), the (pseudo) cystic (type II), the generalized type (type III) and the microscopic type (type IV) of meconium peritonitis.[3] The underlying causes may be divided into three categories.[2]

(a) Bowel obstruction

(b) Idiopathic, and

(c) Cystic fibrosis

CONCLUSION

In conclusion, the diagnosis of meconium pseudocyst should be considered in the setting of foetal bowel obstruction with sequential polyhydramnios, ascites and cyst formation, even in the absence of intra-abdominal calcification.[1,4] Hydrops can also be associated with this type of meconium peritonitis.

REFERENCES

1.Yang WT, Ho SSY, Metreweli C. Antenatal sonographic diagnosis of meconium peritonitis and subsequent evolving meconium pseudocyst formation without peritoneal calcification. Clinical Radiology 1997; 52 : 477-9.

2.Agrawal N, Kriplani A, Bhatla N, Deorari AK. Idiopathic origin of meconium peritonitis. Indian J Paediatrics 2000; 67 (11) : 845-6.

3.Tibboel D, Gaillard JL, Molenaar JC. The "Microscopic" type of meconium peritonitis. Z Kinderchir 1981; 34 (1) : 9-16.

4.Dunne M, Haney P, Sun CC. Sonographic features of bowel perforation and calcific meconium peritonitis in utero. Paediatr Radiology 1983; 13 (4) : 231-3.

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