Congenital segmental dilatation of the intestine: an in-depth review

Abstract Objective Congenital segmental dilatation of the intestine (CSDI) is a rare gastrointestinal condition. We conducted a scoping review through MEDLINE and Google Scholar, collecting data from 1959 through August 2020 to better understand this peculiar disease. Methods The clinical and pathological features of 150 patients were reviewed. Results The mean age was 25.9 days, and 61.3% of patients were male. An antenatal diagnosis was made in 15.3% of patients. Predominant symptoms included abdominal distension (83.9%) and vomiting (61.3%). Pallor and anemia were associated with ileal CSDI. The most common sites of the lesion were the ileum (56%) and colon (27.3%). Associated anomalies occurred in 57.3% of the patients, of which the most common included other abnormalities of the digestive system (69.8%), abdominal wall (19.8%), and cardiovascular system (11.6%). Resection and anastomosis was performed in 83.3% of patients. Postoperative complications occurred in 10%. Normal ganglion cells were commonly found (97.3%), while muscle layer hypertrophy and atrophy were found in 14.7% and 13.3% of the patients, respectively. Abnormal interstitial cells of Cajal were identified in four patients. Death occurred in 12.7% of patients. Demise was significantly associated with the duodenal location of CSDI (Mantel-Cox test, p = 0.002). Conclusion CSDI remains poorly understood, and mortality is associated chiefly with its duodenal location. Further research is needed, and biorepositories should be promptly set up to study this disease in the future better. HIGHLIGHTS What is currently known about the topic? CSDI is a sporadic condition, which can represent a challenge for neonatologists. What new information is contained in this article? Pallor and anemia are found explicitly in ileal CSD, and the duodenal location of CSDI is associated with the highest mortality rate.


Introduction
Congenital segmental dilatation of the intestine (CSDI) is a rare disease characterized by three main features: (a) a three-fold increase of the diameter of the small or large intestine on cross-sectional imaging or intraoperatively, (b) the absence of a mechanical obstruction distal to the lesion, and (c) an abrupt transition from the lesion to the adjacent healthy intestine [1-3].The lesion, mainly unifocal, can be localized anywhere on the intestine, from the duodenum to the rectum.It was described for the first time by Swenson and Rathauser in 1959 [4].Since then, more than 100 cases have been reported worldwide in 2006 [5].Its etiology remains unclear.Postulated etiologies include vascular, neuronal, and mechanic theories [1].
Despite the possible antenatal diagnosis [6], CSDI is mainly diagnosed postnatally, in neonates, with symptoms depending on CSDI location and associated anomalies [2].The diagnosis can be made using different investigations such as contrast studies (upper gastrointestinal series or contrast enema) and ultrasonography.Its management is substantially surgical.It involves the resection of the lesion and the reconstitution of the intestinal continuity by performing an anastomosis with or without a diverting stoma.It seems that the prognosis primarily depends on associated anomalies.
To date, three reviews on CSDI have been carried out, of which the first was in 2015, with 28 patients from a nationwide study in Japan on allied disorders of Hirschsprung's disease or aganglionosis [3].The second report was a literature review of 73 patients, of which 28 patients belonged to the previous Japanese cohort [7].A more recent case series included four patients [2].
In this study, we conducted a scoping review of case reports and case series published from January 1959 through August 2020.The aim was to provide a comprehensive survey on CSDI, including demographic contributing factors, antenatal diagnoses, clinical and laboratory features, comorbidities, treatments, and outcome.

Search strategy
This scoping review was made using PubMed, Medline, and Google Scholar.PubMed is a way to access the MEDLINE database.Still, it actually contains additional content, among others, references to books and chapters, ahead of print and in-process citations, and articles, which may lie outside of the subject scope of MEDLINE.We performed our search of publications targeting CSDI.The detailed search strategy is attached in the appendix.
Inclusion criteria were: (a) reports on CSDI, including its synonyms (ileal dysgenesis, segmental mega ileum, and idiopathic localized dilatation of the ileum) and (b) published from January 1959 through August 2020.Exclusion criteria were: (a) full text not available and no corresponding author's contact or no reply from an author, (b) adult patient (�18 years old), (c) reports not in English, (d) purely theoretical article, (e) no histology available in the report, and (f) missing clinical information.We used a PRISMA-based approach for this review [8].

Study selection
Two authors made the study selection independently (FTAZ and SMM) and performed it manually.First, duplicates were removed.Second, title, and abstract screening were performed by applying inclusion criteria.Exclusion criteria were then verified for articles retained after these first two steps.The reports are summarized in a PRISMA-based flow chart (Figure 1) [8].

Data extraction and analysis
Two authors performed the data extraction (FTAZ and SMM) on an Excel spreadsheet using Microsoft Office TM 2019.A total of 43 variables were grouped within ten themes.They included socio-demographic data, antenatal diagnosis, symptoms, clinical findings, investigations, characteristics of the CSDI lesion, associated congenital anomalies, management, results of pathology, and outcomes.
Data analysis was performed using Statistical Package for the Social Sciences (IBMV R SPSSV R Statistics) version 26.Continuous variables were reported as mean for normally distributed data or median (with quartiles 25 and 75) for not normally distributed data.Categorical variables were presented as a percentage.Concerning the six-month survival, patients were subdivided into two groups: mortality and survival.The Mantel-Cox test delivered the six-month survival (Kaplan-Meier analysis, KMA), with the duodenal location as a factor predicting survival.The difference was statistically significant with a p-value < 0.05 (alpha level of 5%).

Socio-Demographic data
Our review included 150 patients since the first cases were reported in 1959, with an average of 2.5 cases reported annually.Male patients represented 61% of cases, and the male: female sex ratio was 1.59/1.The median age was 0.25 months (0.03 − 31.5), with extremes ranging from a day to 16 years old.Premature patients represented 14% of the 150 patients studied.These findings are detailed in Table 1.

Antenatal diagnosis
Antenatal diagnosis or suspicion of CSDI has been suggested in 23 patients (15.3%), using obstetrical ultrasound.The age of antenatal investigation was able to be extracted in 20 out of 23 antenatally diagnosed patients.The mean gestational age at diagnosis/suspicion was 29.5 (± 18) weeks of gestation.Polyhydramnios was found in 13% of the 23 cases, while gastric dilatation was noted in 8.7%.CSDI was described as an intraabdominal cyst in 52.2% of the 23 cases, followed by intestinal loop dilatation (13%), intraabdominal lesion (8.7%), and pelvic cystic lesion (8.7%), intraabdominal mass (4.4%), and colonic dilatation (4.4%).In two of the 23 patients, the appearance of CSDI was not satisfactorily reported.In 8.7% of 23 patients antenatally diagnosed, the lesion seemed to change its appearance by showing movements during the ultrasound examination.

Symptoms
Duration of symptoms was reported in 98 of the 150 included patients.The median was 24 days (1 − 471.75 days), ranging from 8 h to 10 years.Symptoms were described as chronic or recurrent in 26.7% of the 98 cases.
Among the 85 neonates, symptoms were reported in 62 cases only, while in the 65 older patients, they  were reported in 60 cases only.A comparison of the frequency of symptoms reported in both groups is represented in Figure 2. The timing of meconium passage was reported in 21 neonates.Eleven patients (52.4%) disclosed a delay of the meconium passage.Six of the 21 neonates had an ileal location.We found four colonic CSDI, and a single patient exhibited a jejunal CSDI.Two symptoms were reported in older patients, including abdominal pain in 18 of the 60 older patients (30%) and pallor in 15 of the 60 older patients (25%).Other symptoms in the 60 older patients included diarrhea and lethargy (13.33% for each symptom), melena and blood per rectum (each in 5%, respectively), and loss of appetite (3.3%).
According to the CSDI location, a more detailed presentation is shown in Table 2.

Clinical findings
Results of the physical examination were reported in 33 out of 150 patients.The main finding was palpation of abdominal mass found in 18 of 33 patients (54.5%).It was found in the only patient with the duodenal site, in two of the four patients (50%) with jejunal location, in seven of the 15 patients with ileal CSD (46.7%), and in eight of 13 patients with the colonic site (61.5%).A visible peristalsis was stated in 3 out of 33 patients (9.1%) and was found in one of four patients (25%) with jejunal CSD and two of the 15 patients (13.3%) with an ileal site of CSDI.The nutritional status was reported in 95 of the 150 patients.Twenty-three patients (24.2%) exhibited malnutrition.It was found in five of the seven patients (71.4%) with jejunal CSD, 11 of the 51 (21.6%) with ileal location, and seven of 31 cases (22.6%) of colonic CSD.It was not found in the six remaining cases (four duodenal, one duodenojejunal, and one jejunoileal).

Associated congenital malformations
Different systems were affected by an associated birth defect which was reported in 86 patients (57.3%).The most common associated birth defects were gastrointestinal (i.e. the presence of another gastro-intestinal congenital malformation, different from CSDI) and cardiovascular defects, primarily encountered in duodenal CSD 42.9% of the seven patients.The associated anomalies are shown in Table 3. Sixty associated abnormalities were reported.Those commonly found are shown in Figure 3.Other rare associated birth defects reported at least in two patients included myelomeningocele and annular pancreas in four patients each, alveolo-capillary dysplasia, "mobile" cecum, non-rotatipolydactyly, tyly and trisomy 21 in three patients each, and a chromosomal disorder, cleft lip, cleft palate, colonic atresia, congenital heart disease, diaphragmatic hernia, esophageal atresia, Hirschsprung's disease, undescended testis and ventricular septal defect in two patients each.

Treatment
Conservative management was unsuccessful, and all 150 patients required surgery.A stoma was created before the definitive repair in 26 of the 150 patients (17.3%).The definitive surgical treatment was reported in 138 patients, with details provided in Table 4.

Macroscopy
Lesion length was reported in 91 patients (60.7%).It ranged from 3 to 100 cm, with a mean of 15.1 cm (±12.4 cm).The diameter was reported in 63 patients (42%).It ranged from 2 to 22 cm, with a mean of 7.5 cm (±3.9 cm).A perforation and an ulcer were found in 8 patients (5.3%) each.One patient showed a serosal tear.

Microscopy
The study of ganglion cells of the plexus myoeneric and/or submucosus was reported in all 150 patients.

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Meissner's plexus is located in the submucosal tissue of the intestine, while Auerbach's plexus is located between the circular muscle layer and longitudinal muscle layer in the lower esophagus, stomach, and intestines.In 146 (97.3%), ganglion cells were normal.In two patients (1.3%), hypoganglionosis was diagnosed.In one patient, ganglion cells were qualified as "immature," while another report labeled them as" abnormal."The most common findings of the muscular layer (muscularis propria) were hypertrophy in 22 patients (14.7%) and atrophy in 20 patients (13.3%).In two of the 22 cases, hypertrophy was found only in the internal muscle layer of the muscularis propria.
One of the 20 patients with muscle layer atrophy exhibited such change in the external layer only.In two patients (1.3%), a vacuolization of the muscle layer was reported.Other single findings included "abnormal external muscular layer," angiodysplasia, external layer running perpendicular to the internal layer, fiber disarrangement, inflammatory infiltration, multifocal partial absence of the inner layer, and a sparse distribution of fibers.
The analysis of the submucosa was carried out in 7 patients (4.7%).It disclosed an inflammatory cell infiltration, fibrosis, and lymphangiectasis.In eight patients, single findings included a "caliber-persistent artery," diffuse lymphangioma, edema, lymphoid aggregates, nerve fibers hypertrophy, sclerosis, thickening, and vascular congestion.
A single report found an anomaly in the muscularis mucosae, which was reported as hypertrophic.Three patients reported lamina propria inflammation in two and ectopic ganglion cells in one.Other findings were reported in the mucosa, excluding heterotopy in 11 patients, including erosion in 3 patients (2%), atrophy, edema, and inflammation in 2 patients (1.3%) each.Features of chronic inflammation and the presence of an ulcer were seen in one patient each.
Heterotopy (ectopic presence of tissue in the CSDI lesion) was found in 14 patients (9.3%).Among them, ten had a single heterotopy (71.4%), three had a double one (21.4%),and a triple heterotopy was found in a single patient.Most patients with heterotopy had an ileal location of the lesion: 13 of the 14 patients (92.9%).A single patient had a colonic CSD.In these 14 patients, five different ectopic tissues were identified 19 times.The most common ectopia was gastric (11 of 19, 57.9%), followed by pancreatic (3 of 19, 15.8%) and esophageal (2 of 19, 10.5%).Other ectopic tissues were found in a single patient (5.3% for each): cartilaginous, pulmonary, and striated muscle.
Immunohistochemistry with c-kit (CD117) staining, which is used to identify the interstitial cells of Cajal (ICC), was performed in eight patients (5.3%).Among them, a single patient had a negative result.The remaining seven patients had positive results, including three cases with decreased staining, two with standard staining, and two with a positive finding characterized by thin and sparse ICC.

Outcomes
Complications occurred in 15 patients (10%).These were more frequent in patients with duodenal CSD in 4 of the 10 ten patients with this location, followed by  .2� Surgical technique reported in one patient for each: colorraphy plus end-to-end anastomosis, duodenostomy, ileostomy, partial resection, partial resection plus tapering, posterior sagittal anorectoplasty, resection plus side-to-side anastomosis, tapering plus duodenostomy, tapering plus Soave pull-through, tapering plus side-to-side anastomosis.
the colonic CSD in 5 of the 41 patients, and finally, by ileal CSD, in 6 of the 84 patients.No complication was reported in other locations of CSDI.Twenty-two complications have been reported.They included a persistent pulmonary hypertension of the newborn (PPHN)(four times), peritonitis, and sepsis twice.Other complications have been reported once.They included anastomotic leak, aspiration, mechanical dilatation at the anastomosis, intestinal obstruction, necrotizing enterocolitis, parastomal evisceration, prolonged postoperative ileus, sclerema, hypoglycemia, hypocalcemia, "growth delay," and steatorrhea.
Length of stay (LOS) was reported in four papers (2.7%).It ranged from four to 14 days, with a mean of 9 days.
Survival was reported in 84 patients (56%).It ranged from 6 h to 17 years, with a median of 226.5 days (87.7-730).Six-month survival was reported in 72 patients (48%), of which 17 (22.7%)died.Death was reported in 19 patients (12.7%).Deaths were primarily seen in duodenal CSD, with 70% of the ten patients in that location.In patients with the colonic site, death occurred in 14.6% of the 20 patients and 7.1% of the 43 patients with an ileal area.There were no reported deaths with the other CSDI locations.Patients with associated congenital anomalies had a higher mortality rate (17.1%) than those without an anomaly (8.1%).The cause of death was reported in 13 patients, six of whom (46.2%) had a septic shock.A single cause of death was reported in each of the remaining seven patients: aspiration, barotrauma, cardiac surgery, hypoglycemia plus hyponatremia, kernicterus, pulmonary hypertension, and respiratory distress.
Six-month survival was evaluated using Kaplan-Meyer Analysis (KMA).This statistical analysis included 72 patients reporting at least a six-month survival.Among patients without duodenal CSD, 85.5% were still alive after a six-month follow-up, while 40% of patients with duodenal CSD survived.This difference was statistically significant when analyzed with Log Rank (Mantel-Cox) test, with a p-value of 0.002.The duodenal location was found to be a factor associated with patient demise.Figure 4 shows the KMA curve.
With regard to the antenatal diagnosis, a more comprehensive prenatal screening is mirrored by an increase of more precise ultrasound devices of the last decades [3,59].Most newborns suffered from abdominal distension (83.9%), followed by vomiting (61.3%) [3,12] and delayed meconium passage [3,59].Other studies reported delayed meconium passage in 29-40% of patients.Our study only had data from 21 patients, but 11 (52%) had delayed passage of meconium, so its presence should raise concerns of an anatomic abnormality [3,59].Obstructive signs are common and can be detected with plain film or contrast imaging.
Pallor was exclusively found in ileal CSD, and 80% of anemic patients had ileal CSDI.Anemia may be due to gastro-intestinal bleeding.It can arise from a bowel ulceration due to ectopic gastric tissue.These mechanisms are similar to bleeding in a Meckel's diverticulum.
CSDI leads to a functional obstruction or subobstruction, so, the most common feature were a distended intestinal loop, occasionally associated with an air-fluid level.Depiction of intestinal or colonic dilatation confirms the diagnosis of CSDI.Contrast enema helps differentiate colonic CSD from Hirschsprung's disease in colonic location.There is no transition zone in CSDI as the lesion is connected to the adjacent bowel by an abrupt pattern.When associated malrotation is present, contrast studies may help to diagnose it.Abdominal computed tomography has been less requested in our patients.Its result shows dilated intestinal loop, as reported in the literature (8).Identifying an associated volvulus was reported in seven patients.In patients with suspected CSDI, the first-line investigation would depend on the presentation.In patients with suspected intestinal obstruction, plain x-ray and computed tomography are performed.Contrast studies and abdominal US have been demonstrated useful to improve the accuracy.For patients with associated pallor or anemia (predominantly related to ileal CSD), upper gastro-intestinal series should be preferred to contrast enema, while the latter should be preferred in patients with chronic constipation alone, in our opinion.
We found associated anomalies in 57.3%, which is slightly higher than the numbers reported in the literature, ranging from 35.7 to 49% [7,59].This can be attributed to our population study being larger than the previous reports, with more patients with duodenal locations, in which associated anomalies are more frequently reported.We found, like other authors, that the most common abnormalities were digestive, followed by abdominal wall defects and cardiovascular malformations [12].Multiple malformations were found in 38.4%, nearly double the 19.2% reported in the early literature [12].
The presence of ganglion cells in CSDI remains crucial for the differential diagnosis with other motility disorders of the intestine.Hypoganglionosis, immature or "abnormal" ganglion cells were found in 2.7% of cases.In our opinion, inconsistency in evaluating ICC in CSDI may require a thorough examination with CD117 immunohistochemistry in all CSDI specimens in the future.Despite the low rate of the report of muscle layer abnormalities, muscle disorganization has been suggested to contribute to the etiology of CSDI.Heterotopia also seems not to play a significant role.Finally, the inflammatory changes found in 13% of cases may suggest that chronic inflammation is a consequence rather than an etiological factor of CSDI.
A number of hypotheses have been proposed to explain CSDI.It seems that the neuronal hypothesis is mostly favored.Heller et al. hypothesized that CSDI is secondary to a disorder of separation of the notochord from the endoderm, similar to the occurrence of intestinal duplication and diverticula.Our review seems to support this hypothesis: (a) high frequency of associated malformations, including vertebral ones; and (b) the presence of ectopic tissue, developed from the primitive gastrointestinal tract.
In our review, vertebral-associated anomalies were not systematically identified, and precision of the location of ectopic tissue on the mesenteric side was not reported.Therefore, we overemphasize these aspects' importance for a better understanding of this rare disease in the future.
Surgery is the standard treatment of CSDI.Operative management classically involves resection with primary anastomosis.Depending on the location, other surgical techniques have been performed, such as tapering or partial resection (at the antimesenteric border) for a second duodenal CSD or to preserve the pancreaticobiliary ampulla.For rectosigmoid CSD, classical or modified pull-through can be performed, allowing resection of the lesion.According to associated complications and the patient's general condition and associated digestive malformation, these surgical procedures can be performed with or without a diverting stoma.Overall, the surgical strategy is guided by the location of the CSDI, associated digestive malformation, and the patient's general condition.
In conclusion, CSDI is a rare condition.It mainly presents in neonates, with various symptoms and signs.Pallor and anemia are often found in ileal CSD.It has a good postoperative course, commonly with postoperative complications identified in 10%, mostly in duodenal CSD.Furthermore, our KMA showed that duodenal CSD harbors the poorest survival rate.Despite being a qualitative study, which carries a limitation, it is worth reporting.After all, it may be the basis for setting up an animal model and biorepositories of CSDI specimens shortly.

Figure 2 .
Figure2.Comparison of symptoms between neonates (62 patients) and older children (60 patients).Abdominal distension, vomiting and loss of appetite were more common in neonates, while lethargy, constipation, diarrhea and blood per rectum were more reported in older children.

Figure 3 .
Figure 3. Commonest reported associated anomalies.This shows that most common associated birth defect are: malrotation, anorectal malformations, omphalocele and Meckel's diverticulum patients.

Figure 4 .
Figure 4. Kaplan-Meyer Analysis.This shows a six-month survival in 72 patients with CSDI.Patients with the duodenal location of the CSDI (red) have a lower survival rate compared to those without this location (blue).Mantel-Cox, p ¼ 0.002.

Table 2 .
Symptoms according to the CSDI location.

Table 3 .
Associated congenital malformations by CSDI location as reported in 86 of the 150 included patients.Concurrent congenital malformations of the gastrointestinal tract in patients with CSDI.