Asymptomatic mesenteroaxial gastric volvulus and midgut malrotation in a 84 year old man

Clinical History

We report a case of an 84-year-old man with incidental findings of asymptomatic mesenteroaxial gastric volvulus and migut malrotation on staging CT of thorax, abdomen and pelvis.

Imaging Findings

The patient was diagnosed with prostate cancer (Gleason grade 4) in 1997 treated with luteinizing hormone-releasing hormone analogues. Subsequent staging scans revealed right renal cell carcinoma for which the patient underwent radiofrequency ablation. Routine chest radiograph demonstrated two air-fluid levels in the stomach on both antero-posterior and lateral views(figs 1,2). The stomach was herniated into the thoracic cavity and inverted, with the greater curvature above the lesser curvature and the pylorus pointing downwards. Computed Tomograhy (CT) of the patient's thorax, abdomen, and pelvis was performed for the purpose of disease staging using oral contrast. Intravenous contrast was withheld due to renal impairment. The oesophagus was dilated and the appearance of the stomach demonstrated features of chronic gastric volvulus with inversion and posteroinferior positioning of the pylorus and antrum (fig 3). Distal to the stomach, the gastrointestinal tract showed evidence of midgut malrotation without volvulus, with portions of the midgut revolving around the superior mesenteric vessels forming the “Whirl Sign” (figs 4,5). MRI of the abdomen and pelvis was performed on the patient to characterise the renal tumour and locally stage the prostate carcinoma. The abnormal relation of superior mesenteric vessels is again demonstrated (figs 6,7) with the superior mesenteric vein lying to the left of the superior mesenteric artery in keeping with a midgut malrotation. No surgical intervention was performed to correct the gastric volvulus and midgut malrotation as the patient was asymptomatic.

Discussion

To our knowledge, this is the first reported case of asymptomatic combined secondary gastric volvulus and midgut malrotation. Gastric volvulus is a rare condition whereby the stomach twists on itself by more than 180 degrees and may lead to a closed-loop obstruction and/or strangulation. The worldwide incidence is suggested as 2–6 new patients per million per year¹. Incidence peaks during the 5^th decade of life², commonly secondary to paraesophageal hiatal hernias, diaphragmatic defects, or formation of abdominal adhesions³. In this case, the volvulus was associated with a large hiatal hernia. Gastric volvulus can be classified into organoaxial or mesenteroaxial. In organoaxial volvulus, the most common type, the stomach rotates upwards along its luminal axis, based upon a straight line connecting the cardia and the pylorus. In mesenteroaxial volvulus, torsion of the stomach occurs along the long axis of the lesser omentum in a plane perpendicular to the luminal axis⁶. These can cause obstruction and vascular compromise, leading to acute symptoms of severe epigastric pain, retching, and inability to advance a nasogastric tube beyond the distal oesophagus—the 3 classical findings of Borchardt's triad, diagnostic of acute volvulus. Mortality rate for acute volvulus is about 30% and 10-13% for chronic⁶. Mesenteroaxial volvulus is more likely to be asymptomatic. Simultaneous occurrences of both types have been reported in 2% of cases ³. Radiographic findings of mesenteroaxial gastric volvulus include two air-fluid levels on upright images, one superiorly in the antrum and another inferiorly in the fundus as seen on the plain radiographs (figs 1,2). Organoaxial volvulus is more difficult to diagnose. The stomach lies horizontally and contains a single air-fluid level on upright views. Barium study provides the highest diagnostic value¹, however as intervention was not planned, this was not performed. Plain films and CT with characteristic features were sufficient to establish diagnosis (figs 1-3). Midgut malrotation is more common in younger patients where it frequently presents with symptomatic volvulus, with 60% of reported patients aged 1 month or below and 20–30% between 1 and 12 months⁴ and an overall incidence of 1 in 500 live births⁵. Malrotation occurs during foetal development where embryologic development does not proceed normally. Between weeks 5-8 of foetal development, the gut herniates through the umbilicus. Following this the gut undergoes two stages of rotation around the superior mesenteric artery (SMA), giving a total of 270 degrees counter-clockwise rotation before reentering the abdominal cavity⁷. The range of malrotation can be anywhere between 90 and 270 degrees and predisposes to midgut volvulus and small bowel obstruction. The possibility of midgut volvulus should be investigated in newborns presenting with bilious vomiting. In this case the patient had radiographic evidence of malrotation only without features of volvulus. On CT, the presence of the “Whirl Sign” suggests midgut malrotation ( figs 4,5). Abnormal relationships of the SMA and the superior mesenteric vein are also in keeping with malrotation (figs 6,7). Gastric volvulus and midgut malrotations are rare and may cause acute symptoms leading to mortality. Therefore, even asymptomatic patients require follow-up to allow early identification of complications.

Differential Diagnosis List

Final Diagnosis

Asymptomatic mesenteroaxial gastric volvulus and midgut malrotation.

URL:	https://www.eurorad.org/case/6104
DOI:	10.1594/EURORAD/CASE.6104
ISSN:	1563-4086