Incomplete reversed midgut rotation with 540° volvulus in an adult: a case report

Abstract

Introduction and importance:

Reversed midgut rotation with a retro-arterial transverse colon is a rare cause of adult midgut volvulus, requiring early imaging diagnosis and tailored surgical management.

Presentation of case:

A 40-year-old man with intermittent abdominal distension presented with acute obstruction. CT showed intestinal malrotation and volvulus with the transverse colon passing behind the superior mesenteric artery (SMA). Ladd’s procedure was performed. Recurrent distension on day 5 led to a diverting ileostomy. Three months later, a right hemicolectomy with ileostomy closure was done. Recovery was uneventful.

Clinical discussion:

Reversed intestinal rotation can trap the transverse colon behind mesenteric vessels, leading to obstruction even after Ladd’s procedure. CT findings – such as superior mesenteric artery or vein orientation, duodenojejunal flexure position, cecal location, and the whirl sign – are key for diagnosis and surgical planning. Persistent retro-arterial anatomy may justify elective segmental resection, even in asymptomatic patients.

Conclusions:

Incomplete reverse midgut volvulus in adults is a rare but potentially life-threatening condition. A high index of clinical suspicion, prompt imaging, and early surgical intervention are essential to optimize patient outcomes.

Introduction

Intestinal malrotation is a relatively common congenital anomaly, affecting approximately 0.2% of the general population, with a higher prevalence reported in males compared to females^[1^]. During normal embryonic development, between the 5th and 12th weeks of gestation, the bowel undergoes a series of processes including extrusion into the umbilical cord, a 270° counterclockwise rotation around the superior mesenteric artery (SMA), return to the peritoneal cavity, and the formation of a broad mesentery that anchors the bowel – from the duodenojejunal (DJ) junction to the cecum – to the retroperitoneum, ultimately resulting in the normal positioning and fixation of the bowel^[1,2^]. Any disruption in this process may lead to intestinal malrotation, which can present as either nonrotation or incomplete rotation^[1–3^]. These anomalies are characterized by abnormal positioning of the small intestine and colon, including a medially displaced cecum and the presence of Ladd’s bands, both of which predispose patients to complications such as midgut volvulus^[2,4^].

HIGHLIGHTS

• Adult reversed midgut rotation with 540° volvulus.

• Retro-arterial transverse colon beneath the SMA on CT.

• Early postoperative obstruction after Ladd’s; elective right hemicolectomy.

• Ileocolic anastomosis placed lateral to the SMA/duodenum.

• Mesenteric base broadening to reduce recurrence.

Although intestinal malrotations can present at any age or remain asymptomatic, they typically manifest with symptoms within the first month of life^[3,5,6^]. However, the clinical presentation of intestinal malrotations varies among different age groups^[5^]. During the first year of life, intestinal malrotations typically present with acute symptoms, with vomiting being the most common manifestation^[5^]. However, in older adults, intestinal malrotations tend to present with more chronic symptoms, with abdominal pain being the most common^[5^]. Additional symptoms may include food intolerance, rectal bleeding, weight loss, diarrhea, gastroesophageal reflux, and nausea^[5,7–9^]. Additionally, intestinal malrotation can lead to several complications, with intestinal obstruction being the most common^[6^]. Furthermore, patients undergoing surgery exhibit a relatively high complication rate, with 27% experiencing postoperative complications^[6^]. These complications include pancreatitis, intussusception, short bowel syndrome, ileus, as well as duodenal stricture and hematoma^[6,8^].

Reverse volvulus, characterized by rotation in the opposite direction to the usual pattern, and incomplete volvulus, involving partial rotations less than 360° or atypical rotations such as 540° twists not following the classic pattern, are uncommon variants that may complicate diagnosis.

Intestinal volvulus typically becomes symptomatic and is diagnosed during infancy^[10^]. However, a spectrum of clinical manifestations ranging from asymptomatic cases to chronic gastrointestinal (GI) symptoms and acute presentations has been reported in the literature^[5,11,12^]. Furthermore, due to the relatively low incidence of these cases, some controversies remain regarding their management and treatment^[9^]. Additionally, due to the similarity between the symptoms of intestinal volvulus in adults and those of other GI pathologies, diagnosing the condition in adulthood can be challenging^[5^]. Understanding the embryological basis and the resulting anatomical abnormalities is essential for accurate interpretation of imaging studies and effective operative planning. This report presents a rare adult case of incomplete reverse mid-gut volvulus characterized by a 540° clockwise rotation, and reviews the pathophysiology, diagnostic features, and surgical management strategies. This case report has been prepared in accordance with the SCARE 2025 guidelines^[13^].

Background and detailed pathophysiology

Embryology and normal rotation

During embryologic development, the midgut undergoes a 270° counterclockwise rotation and its mesentery fuses to the posterior abdominal wall, preventing twisting^[1^].

Mechanism of malrotation and volvulus

Malrotation results from incomplete rotation or fixation, creating a narrow mesenteric attachment that permits twisting around the SMA and leads to midgut volvulus. The degree and direction of rotation determine presentation: typical pediatric volvulus is a 360° clockwise twist, while reverse volvulus rotates counterclockwise, and incomplete volvulus involves partial or atypical rotations (e.g., 180°, 270°, 540°).

Vascular consequences

Mesenteric twisting can impair venous and arterial flow, with venous congestion occurring first, followed by arterial compromise, ischemia, necrosis, perforation, and peritonitis. The severity and speed of injury depend on the degree and duration of torsion and collateral circulation.

Clinical presentation in adults

Adults with malrotation and midgut volvulus often present with non-specific symptoms, including intermittent abdominal pain, nausea, vomiting, distension, and bowel obstruction. Chronic cases may cause episodic pain or failure to thrive, while acute presentations usually reflect complete volvulus with ischemia.

Imaging features

Contrast-enhanced CT is the imaging modality of choice in adults suspected of volvulus. Classic radiologic signs include:

• Whirlpool sign: swirling of mesenteric vessels and fat around the SMA, indicating rotation of the mesentery.

• Abnormal SMA–SMV relationship: inversion or crowding of the veins and arteries.

• Abnormal position of the DJ junction and cecum (e.g., DJ not reaching the left of the abdomen; cecum midline or left-sided).

• Bowel dilatation proximal to the transition point and signs of bowel wall thickening or lack of enhancement suggesting ischemia.

Endoscopic contrast studies (upper GI series) can demonstrate a corkscrew or spiral configuration of the proximal small bowel and abnormal DJ position but are less commonly used in unstable adults. CT angiography can additionally assess vascular patency and ischemia.

Treatment is primarily surgical and depends on symptom severity, anatomical findings, and the presence of complications such as obstruction or ischemia.

Timeline

The patient’s clinical course, key CT descriptors, and operative milestones are summarized in Table 1.

Table 1.

Case timeline.

Date/day	Event and management	Key details
Day 0	Emergency laparotomy; Ladd’s after counterclockwise detorsion	CT: volvulus; retro-arterial transverse colon; whirl sign; DJ not in LUQ
POD 5	Diverting loop ileostomy	CT: transition at proximal transverse colon beneath SMA; no ischemia
~3 months	Ileostomy closure + right hemicolectomy	Ileocolic anastomosis lateral to SMA/duodenum; mesenteric base widened
Follow-up at 12 months	Asymptomatic	Normal diet; no recurrence

CECT, contrast-enhanced computed tomography; DJ, duodenojejunal; ED, emergency department; LUQ, left upper quadrant; POD, postoperative day; SMA, superior mesenteric artery.

Case presentation

A 40-year-old man presented to the emergency department with acute colicky abdominal pain, progressive abdominal distension, bilious vomiting, and obstipation. He reported lifelong intermittent bloating and abdominal pain since childhood. Past history was unremarkable except for a laparoscopic right inguinal herniorrhaphy 7 years earlier; he took no medications, denied smoking or alcohol use, and had no relevant family history. On arrival, temperature 37.3°C, heart rate 110 bpm, blood pressure 125/85 mmHg, respiratory rate 16/min, and oxygen saturation 95% on room air. The abdomen was distended with diffuse mild tenderness and no peritoneal signs. Laboratory tests showed mild leukocytosis (11 × 10⁹/L) and mild metabolic acidosis. Plain abdominal radiography demonstrated small-bowel distension. Contrast-enhanced CT revealed intestinal malrotation with the transverse colon coursing posterior to the duodenum and SMA (Fig. 1), generalized small-bowel dilatation, cecum in the mid-abdomen, and a whirl sign consistent with incomplete midgut volvulus (~540°) (Fig. 2). The DJ junction failed to reach the left upper quadrant; the SMA/SMV relationship was normal (Fig. 3).

Figure 1.

Contrast-enhanced CT revealed intestinal malrotation with the transverse colon coursing posterior to the duodenum and SMA.

Figure 2.

Generalized small-bowel dilatation, cecum in the mid-abdomen, and a whirl sign consistent with midgut torsion.

Figure 3.

DJ junction failed to reach the left upper quadrant.

Given these findings, the patient underwent emergency midline laparotomy. Intra-operatively, there was reversed midgut rotation with ~540° midgut volvulus; detorsion was performed counterclockwise. A standard Ladd’s procedure followed – division of Ladd’s bands, broadening of the mesenteric base, orientation of the small bowel to the right and the colon to the left, and appendectomy. The superior mesenteric vein was markedly engorged, and the transverse colon was confirmed to pass beneath the duodenum/SMA; the cecum was freely mobile, lying toward the left upper quadrant. No significant adhesions were present apart from the lateral abdominal wall. We did not fix the abdominal viscera to the abdominal wall. He was admitted to the surgical ward and recovered initially. Histopathology of the appendix showed distal fibrous obliteration.

During the first 4 postoperative days, he was stable with no complaints. On postoperative day 5, he developed recurrent abdominal distension with diet intolerance. Repeat CT demonstrated a transition at the proximal transverse colon beneath the SMA without ischemia (Fig. 4). Re-exploration revealed no recurrent volvulus; a diverting loop ileostomy was fashioned for decompression during the inflammatory phase. Symptoms settled and the stoma functioned well.

Figure 4.

Transition at the proximal transverse colon beneath the SMA without ischemia.

At approximately 3 months, while asymptomatic, he underwent elective ileostomy closure combined with right hemicolectomy to definitively address the retro-arterial transverse colon. The resection included the terminal ileum, ascending colon, and the retro-arterial transverse colon segment; an ileocolic anastomosis was constructed lateral to the SMA/duodenum, and the mesenteric base was further widened. Gross examination of the specimen measured 49 cm; the mucosa was grossly unremarkable with reduced luminal caliber. Microscopy showed preserved large-bowel architecture; one reactive lymph node; attenuation of the muscularis propria in the distal small intestine; and increased lamina propria inflammatory cells at the ileostomy site. Across all operations, mesenteric veins and the SMA anterior to the colon appeared markedly dilated and engorged, consistent with longstanding venous congestion. The postoperative course was uneventful, and at 12-month follow-up, he tolerated a normal diet with regular bowel movements and no recurrent obstructive symptoms.

Discussion

In this case report, we describe an adult patient with chronic symptoms attributable to intestinal malrotation who developed acute midgut volvulus, followed by an early postoperative episode of GI obstruction despite treatment, and later underwent elective definitive surgery at ileostomy takedown. Although the patient faced the risk of severe complications, timely diagnosis and appropriate management led to favorable outcomes after the acute episode.

Intestinal malrotation is predominantly diagnosed in infants and toddlers, with over 90% of patients becoming symptomatic and identified within the first year of life. In contrast, fewer than 0.5% of cases are diagnosed during adulthood, underscoring the rarity of this condition in the adult population^[14,15^]. Although acute symptomatic presentation of intestinal volvulus in adulthood has been reported in the literature, the majority of affected individuals become symptomatic during their twenties^[3,14–19^]. This case is notable in that the patient’s chronic symptoms went unrecognized, with no definitive diagnosis made until the age of 40, when he developed acute volvulus. Nonetheless, it is important to note that intestinal malrotation has been reported in patients as old as 85 years^[18^]. Although there are some similarities, the clinical presentations of intestinal volvulus differ between infants and adults^[5^]. In adults, symptoms typically develop more gradually, with a higher proportion presenting with abdominal pain and diarrhea^[5^]. Additionally, abdominal pain and vomiting are the most common presenting symptoms in adult patients, occurring in both chronic and acute cases^[9^]. These findings are consistent with the clinical presentation described in this case report. Therefore, despite its rarity, intestinal volvulus should be considered in the differential diagnosis of adults presenting with chronic constipation, given the potentially devastating consequences such as midgut volvulus^[20^].

Symptoms related to intestinal volvulus may persist in adults even after surgery. While surgical correction of volvulus is highly effective in children and infants – with over 80% of patients achieving complete symptom resolution – persistent symptoms following surgery are more common in adults, affecting up to 30% of cases^[5^]. A study demonstrated that approximately 80% of adult patients who underwent surgical management for intestinal volvulus experienced persistent symptoms within the first year postoperatively, with abdominal pain, constipation, and food intolerance being the most common complaints^[21^]. Additionally, postoperative abdominal obstruction following Ladd’s procedure has been reported in approximately 46% of patients during a 15-year follow-up period^[22^]. Similar to our course, several studies have reported adult patients experiencing recurrent bowel obstruction following Ladd’s procedure^[23^]. Although variations exist across studies, adhesions and recurrent volvulus appear to be the most common causes of bowel obstruction in patients undergoing Ladd’s procedure^[24,25^]. The primary risk factor identified for recurrent bowel obstruction following Ladd’s procedure is intestinal ischemia, which may result in adhesions and subsequent obstruction^[26^]. This underscores the importance of timely diagnosis and management of bowel obstruction in the context of intestinal volvulus to prevent ischemia and other adverse outcomes.

In our patient, a contrast-enhanced abdominal CT scan was pivotal for diagnosis. While imaging modalities play a crucial role in diagnosing intestinal malrotation in both pediatric and adult populations, the preferred imaging techniques differ between these groups^[12^]. In infants and children, the upper GI series is the most commonly employed diagnostic modality for intestinal malrotation, whereas computed tomography is preferred in adults^[5,12^]. Additionally, specific anatomic features observed on CT scans can aid in predicting the necessity for surgical intervention in patients with intestinal volvulus^[27^]. Specifically, among patients with partial duodenal rotation and right-sided positioning of the main jejunal segment, the cecum was more frequently located on the right in those managed conservatively compared to patients who required surgical intervention^[27^]. Attention to such details may assist in identifying patients who could benefit from surgical intervention, facilitating timely management and improving clinical outcomes.

This case report has several limitations worth noting. First, given the recurrent and chronic nature of the patient’s symptoms prior to definitive correction, the possibility of long-term complications cannot be excluded. As the patient was not followed up for an extended period after the third surgical procedure, the risk of late complications remains uncertain. Second, certain genetic factors have been identified that predispose individuals to the development of intestinal malrotation^[28^]. However, a genetic assessment was not performed for the patient, which constitutes an additional limitation of this case report.

Conclusions

Adult intestinal malrotation should remain in the differential for chronic, intermittent abdominal pain or constipation. In acute presentations, rapid cross-sectional diagnosis and timely surgery mitigate complications; intestinal ischemia portends poorer postoperative outcomes. In adults, contrast-enhanced CT is the modality of choice, and reports should explicitly document SMA/SMV orientation, DJ position, cecal location, and objective signs of obstruction (e.g., whirl sign). When unfavorable retro-arterial anatomy persists after Ladd’s – particularly a retro-arterial transverse colon with a reproducible transition – planned definitive correction with colectomy (e.g., right hemicolectomy) may be warranted.

Ethical approval

The Ethics Committee of Tehran University of Medical Sciences approved the study protocol.

Consent

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

Sources of funding

This study was performed using no special grant or funding.

Author contributions

O.R.: Conceptualization; Investigation; Resources; Data curation; Writing – original draft; Visualization. A.A. Methodology; Validation; Writing – review & editing; Supervision; Project administration. K.A.: Writing – review & editing; Data curation. N.M.: Investigation; Data curation. M.M.: Investigation; Data curation.

Conflicts of interest disclosure

All authors declare that there is no conflict of interest to disclose.

Research registration unique identifying number (UIN)

Not applicable.

Guarantor

Alireza Abkhoo.

Provenance and peer review

Not commissioned; externally peer-reviewed.

Data availability statement

All data underlying this report are included in the article. Additional de-identified information is available from the corresponding author on reasonable request.

SCARE compliance statement

This case report has been reported in line with the SCARE 2025 criteria.