INTRODUCTION

Omental cysts are the rarest forms of intra-abdominal masses, occurring primarily in children. They often present with symptoms similar to other more common abdominal pathologies and are frequently discovered incidentally on imaging studies. The incidence of mesenteric and omental cysts is approximately 1 in 20,000 among children, with an even lower occurrence in infants [1]. The first report of an omental cyst was published in 1852 by Gairdner [2]. Omental cysts have uncertain etiologies, including lymphangioma, failure of fusion of mesenteric leaves, and deficiency of the lymphatico-venous shunt. They have a variety of presentations depending on their number, location, size, and content. They can also present with features of an acute abdomen due to intestinal obstruction, bleeding into the cyst, torsion, or rupture of the cyst [3]. Due to these diverse clinical presentations, preoperative diagnosis is challenging, especially in resource-limited settings. The diagnostic procedures include ultrasonography and contrast-enhanced CT scans, which provide more details about the extension and properties of the lesion [4]. Since no medical therapy is available, the only treatment option is complete surgical removal. Open resection is preferred over laparoscopic excision to avoid spillage [5].

Given the rarity of omental cysts, we hereby report a case of a large multiloculated omental cyst in a 5-month-old infant presenting with an acute abdomen.

This case report aims to highlight the uncommon site and age of clinical presentation of a multiloculated omental cyst presenting as an acute abdomen and discuss the diagnostic process and management strategies. The case report also shows the need for a high Index of suspicion and early diagnostic imaging for pediatric patients.

CASE AND PRESENTATION

A 5-month-old male infant presented to the emergency department with a 48-hour history of irritability, vomiting, abdominal distension, and abdominal pain. The pain was diffuse but more pronounced in the periumbilical region. His mother also noticed new-onset abdominal distension. The child demonstrated decreased appetite and vomiting. His last bowel movement was the previous evening and was normal.

Upon presentation, the child was febrile (37.7°C), tachycardic (PR-144 bpm), and tachypneic (RR-54 bpm). On examination, the patient’s abdomen was soft but distended, with tenderness to palpation around the epigastric and umbilical regions. Laboratory findings were significant for leukocytosis (WBC-14,000), hypoalbuminemia (albumin-2.2 g/dL), and an elevated CRP (38 mg/L) but were otherwise unremarkable.

Figure 1: CT scan report

A transabdominal ultrasound was performed, which demonstrated a large, well-defined, multiloculated cystic lesion occupying the abdominal cavity. A contrast-enhanced CT scan revealed a large encapsulated cystic abdominal lesion with multiple septae, measuring approximately 11.1 cm × 7.8 cm, extending from the subhepatic region inferiorly to the mid and lower abdomen. Both imaging studies noted the cyst exerting a mass effect on the small bowel and colon.

Figure 2: Operating room for an exploratory laparotomy

Figure 3: Postoperative recovery

The patient was initially admitted to the pediatric department and subsequently referred to the pediatric surgery department. The patient was rehydrated with saline, started on intravenous meropenem and metronidazole, given analgesics, and had a nasogastric tube inserted for decompression.

The following day, the patient was taken to the operating room for an exploratory laparotomy. Upon entering the peritoneal cavity, a large multiloculated thin-walled cyst was apparent, occupying most of the mid and lower abdomen. The cyst contained fluid and appeared multilocular. It was carefully elevated out of the abdomen and traced to its origin in the greater and lesser sacs. The thin wall of the cyst required careful handling to avoid rupture.

The inferior and lateral borders of the cyst were continuous with the greater omentum, with a vascular pedicle. The cyst was separated from the omentum using electrocautery and ligation. The superior attachment of the cyst was then explored, revealing its origin from the confluence of the transverse mesocolon and the inferior aspect of the tail of the pancreas.

The cyst was completely excised and sent for histopathological examination. Fluid from the cyst was aspirated and sent for analysis. Immunohistochemical analysis was not performed.

The infant had an uneventful postoperative recovery and was discharged on the fifth postoperative day. The patient was seen in the hospital two weeks after discharge and was doing well.

DISCUSSION

Omental and mesenteric cysts are rare entities, differentiated by their location of occurrence, with a reported incidence of 1 in 20,000 admissions to a children’s hospital [6].

Mesenteric and omental cysts are thought to represent benign proliferations of ectopic lymphatics that lack communication with the normal lymphatic system [7]. Omental cysts are restricted to the lesser or greater omentum [8]. The present case describes a large omental cyst that developed on a pedicle from the greater omentum in the region of the transverse colon. Mesenteric and omental cysts can be simple or multiple, unilocular or multilocular, and may contain hemorrhagic, serous, chylous, or infected fluid [2-9].

Our patient had an 11.1 cm × 7.8 cm multilocular cystic mass containing hemorrhagic fluid. Clinical presentations include an abdominal mass, abdominal distension, abdominal pain, and decreased appetite with vomiting [10]. Compression of the portal vein and respiratory distress are additional symptoms caused by the progressive enlargement of the cyst [10]. The most common physical finding of a mesenteric cyst is a compressible abdominal mass, movable transversely but not longitudinally, whereas omental cysts are freely movable [11].

Between 11% and 19% of patients present with acute abdominal symptoms due to torsion, bleeding, or rupture of the cyst [10].

The most prevalent mode of acute abdomen in children is small bowel obstruction. The differential diagnosis includes intestinal duplication, ovarian cyst, choledochal cyst, pancreatic cyst, hydatid cyst, renal cyst, hydronephrosis, and cystic teratoma. A correct preoperative diagnosis of an omental cyst has been made in only about 13.25% of reported cases [10]. The diagnosis requires a high index of clinical suspicion and thorough examination with imaging studies.

Our patient underwent ultrasonography and contrast-enhanced CT scanning, which allowed for precise localization of the mass and diagnosis before surgical intervention [10]. Ultrasonography is often the initial imaging modality of choice for diagnosing omental cysts [4-7]. It typically reveals a fluid-filled cystic structure, commonly with thin internal septa and sometimes with internal echoes from debris, hemorrhage, or infection [7]. Abdominal CT scanning provides additional information and can confirm the organ of origin of the cyst [7]. Complete excision of the omental cyst is now considered the preferred treatment of choice [3-5]. Bowel resection is rarely necessary, and recurrence is uncommon [3]. Laparoscopic resection of small cysts can be performed, but laparotomy is recommended when a minimally invasive approach may not allow for safe resection without rupture of the cyst.

CONCLUSION

This 5-month-old infant presented with abdominal pain, vomiting, gradually increasing abdominal distension, and subclinical early satiety. He was found to have an omental cyst and underwent successful surgical resection. This case highlights a rare but significant cause of acute abdomen in infants. Clinicians should maintain a high index of suspicion for omental cysts in similar presentations, as timely diagnosis and intervention can lead to favorable outcomes.

Acknowledgments:

I would like to sincerely acknowledge all contributors who played a vital role in the completion of this study. We are also grateful to the parents for providing consent to report this case. We are again thankful to Dr. Md. Shah Jahan for editing the manuscript.

Conflict of Interest: There are no conflicts of interest among the authors.

Source of Funding: None.

REFERENCES

1. Walker AR, Putnam TC. Omental, mesenteric, and retroperitoneal cysts: a clinical study of 33 new cases. Ann Surg. 1973;178(1):13–9.
2. Gairdner WT. A remarkable cyst in the omentum. Trans Pathol Soc Lond. 1852;3:1851.
3. De Perrot M, Bründler MA, Tötsch M, Mentha G, Morel P. Mesenteric cysts: Toward less confusion? Dig Surg. 2000;17(4):323–8.
4. Tan JJ, Tan KK, Chew SP. Mesenteric cysts: An institution experience over 14 years and review of literature. World J Surg. 2009;33(9):1961
5. Beahrs OH, Judd ES Jr, Dockerty MB. Chylous cysts of the abdomen. Surg Clin North Am. 1950;30(4):1081–96.
6. Vanek VW, Phillips AK. Retroperitoneal, mesenteric, and omental cysts. Arch Surg. 1984;119(7):838–42.
7. Steyaert H, Guitard J, Moscovici J, Juricic M, Vaysse P, Juskiewenski S. Abdominal cystic lymphangiomas in children: benign lesions that can have a proliferative course. J Pediatr Surg. 1996;31(5):677–80.
8. Ricketts RR. Mesenteric and omental cysts. In: Grosfeld JL, O’Neill JA Jr, Coran AG, Fonkalsrud EW, editors. Pediatric Surgery. 5th ed. Philadelphia: Mosby Elsevier; 1998. p. 1269–75.
9. Prakash A, Agrawal A, Gupta RK, Sanghvi B, Parelkar S. Early management of mesenteric cyst prevents catastrophes: a single centre analysis of 17 cases. Afr J Paediatr Surg. 2010;7(3):140–3.
10. Hassan M, Dobrilovic N, Korelitz J. Large gastric mesenteric cyst: case report and literature review. Am Surg. 2005;71(7):571–3.
11. Kurtz RJ, Heimann TM, Beck AR, Holt J. Mesenteric and retroperitoneal cysts. Ann Surg. 1986;203(1):109–12.