Small bowel volvulus due to a mesenteric lipoma: a case report

Abstract

Introduction:

Small bowel obstruction is a common surgical emergency, most often caused by adhesions or hernias. Rarely, benign mesenteric tumors, such as lipomas, can act as a fulcrum for volvulus and lead to chronic or acute obstruction.

Case presentation:

We report on a 63-year-old male with a 2-year history of recurrent subocclusive episodes. Abdominal computed tomography demonstrated a chronic-appearing small bowel volvulus with engorged mesenteric vessels, and magnetic resonance imaging (MRI) confirmed the presence of a 7 cm benign mesenteric lipoma in the right iliac fossa. The patient underwent elective laparotomy, which revealed a chronic volvulus of the jejunum, 2.5 m from the duodenojejunal junction, secondary to the lipoma. Detorsion and complete resection of the mass were performed. Postoperative recovery was uneventful, and histology confirmed a benign lipoma. At 6-month follow-up, the patient remained asymptomatic.

Discussion:

Mesenteric lipomas are rare tumors, typically asymptomatic but may be complicated by volvulus, causing bowel obstruction. Imaging with computed tomography and MRI is essential to establish the diagnosis, confirm the benign nature of the mass, and guide surgical planning. Surgical excision is curative, with an excellent prognosis.

Conclusion:

A mesenteric lipoma should be considered in patients with recurrent, unexplained small-bowel obstruction. Cross-sectional imaging allows accurate diagnosis, and surgical excision provides definitive treatment.

Introduction

Small bowel obstruction (SBO) is a frequent surgical emergency, responsible for up to 16% of acute abdomen cases and the majority of intestinal obstructions. The leading causes include postoperative adhesions, hernias, and tumors, while rarer etiologies such as volvulus, intussusception, and mesenteric tumors account for a small proportion^[1^].

Small bowel volvulus, defined as axial rotation of the intestine and its mesentery, is an uncommon but potentially life-threatening cause of SBO. It may arise spontaneously or be triggered by predisposing factors such as malrotation, prior surgery, or mesenteric masses^[2^].

Mesenteric lipomas are rare benign adipose tumors, usually asymptomatic and discovered incidentally. However, when large or strategically located, they can provoke volvulus and result in acute or chronic intestinal obstruction^[3^]. Only a few cases of small bowel volvulus secondary to a mesenteric lipoma have been described in the literature.

HIGHLIGHTS

• Rarity of condition: Mesenteric lipomas are uncommon benign tumors of adipose tissue that only infrequently become symptomatic.

• Mechanism of complication: When large or pedunculated, a mesenteric lipoma may act as a pivot point, leading to small bowel volvulus with acute intestinal obstruction.

• Clinical presentation: Patients often present with sudden abdominal pain, vomiting, and distention, making the clinical picture indistinguishable from other causes of bowel obstruction.

• Diagnostic value of imaging: A computed tomography scan is crucial, typically showing a well-defined fatty mass associated with twisted bowel loops (whirl sign), supporting the diagnosis.

• Treatment and outcome: Surgical intervention is required, combining volvulus reduction and tumor excision, and generally resulting in excellent postoperative recovery with a low risk of recurrence.

This work is reported in line with the SCARE criteria^[4^].

Case presentation

A 63-year-old male was admitted to our department with a history of recurrent abdominal discomfort and subocclusive episodes evolving over the past 2 years. These episodes were characterized by diffuse abdominal pain, distension, nausea, and spontaneous resolution within hours. Although the patient had experienced recurrent subocclusive episodes for approximately 2 years, he had not previously sought medical attention because the symptoms resolved spontaneously within a few hours. Consequently, no abdominal imaging studies or other diagnostic investigations had been performed before the current admission.

His medical history was unremarkable except for a laparotomy performed twenty years earlier for a perforated duodenal ulcer. He was not on any chronic medications and reported no family history of gastrointestinal disease.

On admission, the patient was hemodynamically stable. Physical examination revealed a soft, symmetrical abdomen with normal bowel sounds, no tenderness, and no palpable masses. Digital rectal examination was unremarkable. Laboratory investigations, including complete blood count, electrolytes, and renal and liver function tests, were within normal limits, with no signs of systemic inflammation.

Contrast-enhanced abdominal computed tomography (CT) revealed a chronic-appearing small bowel volvulus, with mesenteric vascular engorgement and the development of venous collaterals. A well-circumscribed mesenteric fatty mass was identified upstream of the volvulus. The “whirl sign” of the twisted mesentery was also noted (Fig. 1). Further characterization with abdominal magnetic resonance imaging (MRI) confirmed the fatty nature of the mass, consistent with a mesenteric lipoma, measuring 7 cm in diameter and located in the right iliac fossa. No features suggestive of malignancy, such as infiltration or irregular margins, were observed (Fig. 2).

Figure 1.

CT scan image showing a fatty mass and the whirl sign, as evidence of small bowel volvulus.

Figure 2.

MRI of the abdomen confirming a mesenteric lipoma shows a well-circumscribed, homogeneous, hyperintense fatty mass measuring 7 cm in the right iliac fossa (arrow), consistent with a benign lipoma.

The patient was scheduled for elective surgery. Through a midline laparotomy, exploration revealed a chronic small bowel volvulus involving the jejunum 2.5 m distal to the duodenojejunal junction. The volvulus was found to be secondary to a well-encapsulated mesenteric lipoma, measuring 7 × 6 × 5 cm, firmly attached to the mesentery. No signs of ischemia or necrosis were present (Fig. 3). The surgical procedure consisted of careful detorsion of the volvulus, followed by complete resection of the lipoma while preserving the adjacent bowel.

Figure 3.

(A) Intraoperative findings of small bowel volvulus. The jejunal loops are rotated around the mesentery, approximately 2.5 m from the duodenojejunal junction, centered on the mesenteric lipoma. (B) The resected specimen.

The postoperative course was uneventful. The patient resumed oral feeding on postoperative day 2 and was discharged on day 5 in good condition. Histopathological examination confirmed the diagnosis of a benign mesenteric lipoma composed of mature adipocytes without atypia. At 6-month follow-up, the patient remained asymptomatic with no evidence of recurrence.

Discussion

Mesenteric lipomas are uncommon benign tumors composed of mature adipose tissue. While lipomas are frequently observed in subcutaneous tissues, their occurrence in the mesentery of the small intestine is rare, accounting for only a small fraction of intra-abdominal lipomas^[5^]. These tumors are usually asymptomatic and discovered incidentally, but in some cases, they may present with nonspecific gastrointestinal symptoms or complications such as bowel obstruction, volvulus, or bleeding^[6^].

Small bowel volvulus due to a mesenteric lipoma is exceedingly rare. The volvulus occurs when the lipoma acts as a pivot point around which the small intestine rotates, potentially leading to chronic intermittent obstruction or acute ischemia. Chronic volvulus can promote venous congestion, mesenteric edema, and the formation of venous collaterals, as observed in our patient. In the absence of timely intervention, this condition may progress to strangulation, necrosis, and perforation, highlighting the need for high clinical suspicion and early imaging.

Clinical symptoms are often vague, including intermittent abdominal pain, bloating, and subocclusive episodes, which can delay diagnosis^[7^]. Our patient experienced 2 years of spontaneously resolving subocclusive episodes, reflecting the chronic and intermittent nature of mesenteric volvulus. Physical examination is frequently unremarkable, as lipomas are soft, mobile, and rarely palpable, especially in patients with intra-abdominal fat or previous surgeries^[3^].

Contrast-enhanced abdominal CT was the initial diagnostic tool. It revealed a chronic-appearing small bowel volvulus, evidenced by the classic “whirl sign” – a spiral configuration of the mesenteric vessels and fat around a central axis. This finding strongly suggested mesenteric torsion. Associated features included engorged mesenteric veins and the development of venous collaterals, reflecting the chronic nature of the volvulus^[8^]. In addition, abdominal CT demonstrated a well-circumscribed mesenteric fatty mass located upstream of the twisted loops. The lesion exhibited homogeneous fat attenuation without internal septations or solid nodules, findings typical of a lipoma.

Given the need to further characterize the lesion and rule out liposarcoma, an abdominal MRI was performed. The mass appeared as a well-encapsulated lesion, hyperintense on both T1- and T2-weighted images, with complete signal suppression on fat-suppressed sequences. No irregular margins, thick septa, or non-adipose enhancing components were detected, features that would raise suspicion for liposarcoma^[9^]. These findings confirmed the diagnosis of a benign mesenteric lipoma.

In our case, the combined CT and MRI findings were decisive. CT established the presence of volvulus and demonstrated its vascular impact, while MRI confirmed the benign nature of the mass. This preoperative certainty allowed us to plan a conservative surgical approach – limited to detorsion of the small bowel and excision of the lipoma – rather than a more radical resection. Without imaging, the differential diagnosis would have remained broad, ranging from mesenteric cysts to liposarcoma, potentially complicating surgical decision-making.

Thus, in our patient, imaging not only clarified the etiology of recurrent subocclusion but also provided essential guidance for safe and targeted operative management.

Surgery is the definitive treatment for symptomatic mesenteric lipomas. The approach involves careful detorsion of the affected bowel and complete excision of the lipoma. In our case, a median laparotomy allowed thorough exploration and safe resection. Laparoscopic management has been reported in selected cases but may be limited in chronic volvulus with dense adhesions or large masses. Preservation of bowel length is crucial, particularly in chronic cases where ischemic changes may be present.

Few cases of small bowel volvulus secondary to mesenteric lipoma have been reported. Most cases describe adult patients presenting with intermittent abdominal pain, nausea, or vomiting. The majority required surgical intervention, with favorable outcomes^[7^]. This reinforces the importance of considering mesenteric lipoma as part of the differential diagnosis in recurrent subocclusive syndromes, especially in patients with prior abdominal surgeries, which may alter mesenteric anatomy and predispose patients to torsion.

Postoperative prognosis is excellent following complete excision, with minimal risk of recurrence. Long-term follow-up primarily involves clinical evaluation to monitor for recurrent symptoms. Malignant transformation is extremely rare but must be ruled out preoperatively based on imaging features suggestive of atypia, such as irregular margins or rapid growth.

Conclusion

Mesenteric lipoma is a rare cause of chronic small bowel volvulus and recurrent subocclusive episodes. In patients with unexplained intermittent bowel obstruction, recognition of a mesenteric fatty mass associated with the whirl sign on imaging should raise suspicion for this diagnosis. Complete surgical excision is curative and prevents potentially life-threatening complications.

Ethical approval

Not applicable. Our institutions require no ethical approval for case reports.

Consent

Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.

Sources of funding

Not applicable.

Author contributions

S.A.: Investigation, data curation, literature review, writing – original draft, and writing – review and editing. M.H.: Conceptualization, methodology, writing – original draft, and correspondence. A.S.: Investigation and data curation. H.M.: Investigation, resources, and validation. A.H.: Supervision, validation, and writing – review and editing. M.K.: Conceptualization, supervision, project administration, and validation. All authors have read and approved the final manuscript and agree to be accountable for all aspects of the work.

Conflicts of interest disclosure

All authors declare that they have no conflicts of interest.

Research registration unique identifying number (UIN)

Not applicable.

Guarantor

Souhaib Atri.

Provenance and peer review

Not applicable.

Data availability statement

Not applicable.