Presentation
Intermittent colicky abdominal pain for the past 3 days, associated with vomiting and poor oral intake.
Patient Data
The abdominal radiograph showed dilated bowel loops which were predominantly displaced to the left by a lucent area at the right iliac fossa, with no pneumoperitoneum.
Ultrasound revealed a well-defined homogenous hyperechoic mass at the right iliac fossa, size 5 x 5 x 7 cm (AP x W x CC) which was isoechoic to mesenteric fat with mesenteric vessels within. Further assessment of the initial appearance of “pseudokidney sign” was twisting of small bowels with a whirlpool sign indicative of volvulus and several mesenteric nodes.
A homogenous fat density mass at the right iliac fossa with mean attenuation of -100HU, causing a whirlpool sign of twisted mesentery, SMA and SMV. Proximal bowel dilatation noted. No evidence to suggest bowel ischemia.
Conclusion: Mesenteric lipoma with volvulus.
The pediatric surgical team proceeded with laparotomy. Intraoperatively, there was a yellow dumbbell mesenteric lipoma measuring 8 x 4 cm over mid jejunum, causing volvulus of the small bowels. The mass was completely encapsulated and easily peeled off from the mesentery with no defect post-excision. Bowels were all healthy, and there was no ischemia. Microscopy: Sections show thinly encapsulated tumor composed of mature and uniform adipocytes arranged in sheets and lobules separated by fibrovascular septae. Areas of stromal hemorrhages noted. No atypical stromal cell or lipoblast is identified. Interpretation: Consistent with mesenteric lipoma.
HISTOPATHOLOGY REPORT
*Intraoperative findings: Lipoma of the mesentery over the mid jejunum.
Macroscopy: Received a piece of yellowish to brownish tissue measuring 65 x 50 x 25 mm. The serial section shows a yellowish-to-brownish cut surface with areas of hemorrhage. Representative sections are submitted in 5 blocks with external surface inked green.
Case Discussion
The postoperative period was uneventful and the child was discharged from the hospital.
Upon follow-up, the patient gained weight and was tolerating orally well.
The diagnosis of mesenteric lipoma could be made pre-operatively with ultrasound. This is usually visualized as a well-encapsulated homogenous hyperechoic mass. If there is an associated complication of volvulus, ultrasound can be used to see the twisting of the bowel and mesenteric vessels. Cross-sectional imaging such as CT can provide more information and potential complications such as bowel ischemia.
Case courtesy of Dr. Lau Kiew Siong, Consultant Radiologist, Sarawak General Hospital, Malaysia.