Gastrointestinal Tract

Abstract

In a usual pediatric pathology routine, about 50% of the specimens received come from the department of pediatric gastroenterology. Probably, the importance of new acquisitions in definitions of pediatric gastroenterology disorders allowed identifying new definitions. The eosinophilic esophagitis is an allergic inflammatory condition of the esophagus that involves the recruitment of eosinophils and has increased incidence in several areas of the globe. Gluten-sensitive enteropathy is one of the great mimickers and one of the significant causes of malabsorption. In this chapter, the delineation of the embryology and inflammatory and neoplastic conditions of the esophagus, stomach, small bowel, and large bowel is presented.

Multiple Choice Questions and Answers

• GIT-1 In esophageal atresia (EA), the upper esophagus is not connected to the lower esophagus (atretic), and in about nine out of ten newborns, there is a tracheoesophageal fistula (TEF) as well, in which the trachea and the esophagus are connected. An isolated EA/TEF occurs in about 40% of affected individuals, while the remaining have EA/TEF associated with other congenital disabilities or as part of a multiple congenital anomaly or genetic syndrome. Esophageal atresia is NOT associated with which of the following genetic syndromes?

  • (a) CHARGE syndrome

  • (b) Trisomy 18 syndrome

  • (c) VACTERL association

  • (d) Neurofibromatosis type I

• GIT-2 Wolf-Hirschhorn syndrome (WHS) is a genetic syndrome with diaphragmatic defect and typical craniofacial features in infancy consisting of “Greek warrior helmet” appearance of the nose, microcephaly, high anterior hairline with prominent glabella, hypertelorism, epicanthus, highly arched eyebrows, micrognathia, short philtrum, and downturned corners of the mouth, as well as poorly formed ears with pits/tags. There is prenatal-onset growth deficiency with postnatal growth retardation and hypotonia. Internal findings reveal structural brain abnormalities, congenital heart defects, hearing loss, gut, and urinary tract malformations, as well as skeletal anomalies. Which chromosomal aberration is associated with WHS?

  • (a) Heterozygous deletion of the WHS critical region (WHSCR) on chromosome 14p3

  • (b) Heterozygous deletion of the WHS critical region (WHSCR) on chromosome 4p16.3

  • (c) Heterozygous deletion of the WHS critical region (WHSCR) on chromosome 21p12.3

  • (d) Heterozygous deletion of the WHS critical region (WHSCR) on chromosome 3p16.3

  • (e) Heterozygous deletion of the WHS critical region (WHSCR) on chromosome 4p12.3

• GIT-3 Necrotizing enterocolitis (NEC) is a life-threatening condition that usually affects premature babies and can have clinically significant long- and short-term consequences. Which of the following statements is NOT correct?

  • (a) The modified Bell staging system is used for scoring NEC.

  • (b) NEC presentation can include lethargy, temperature volatility, episodes of apnea, bradycardia/hypotension, and reduced glucose homeostasis.

  • (c) NEC presentation can be confused with sepsis.

  • (d) Blood culture results are positive in about 90% of patients at the onset of NEC.

  • (e) Typical bacteria seen are Clostridium perfringens, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Proteus mirabilis.

  • (f) The presence of Candida spp. in these cultures can indicate more severe disease.

• GIT-4 A 2-week-old infant presents with constipation and the diagnosis of Hirschsprung’s disease is suspected by an abnormal result of the anal manometry. A rectal suction biopsy is sent to the pathologist. What are the criteria to diagnose Hirschsprung’s disease on hematoxylin and eosin staining of a rectal suction biopsy?

  • (a) Presence of parasympathetic ganglion cells in the submucosal plexus and hypertrophy of the nerve fibers

  • (b) Absence of the nerve fibers that innervate the submucosa of the rectum

  • (c) Absence of parasympathetic ganglion cells in the submucosal plexus and myenteric plexus in addition to hypertrophy of the nerve fibers

  • (d) Absence of parasympathetic ganglion cells in the submucosal plexus and hypertrophy of the nerve fibers

  • (e) Atrophy of the mucosa with the presence of parasympathetic ganglion cells

• GIT-5 A 15-year-old boy presents with a 4-week history of bloody diarrhea, periumbilical pain, low fever, and weight loss. The family physician investigates stool culture for bacteria, ova, and parasites, but they were negative. According to the boy and his family, the child had these symptoms once before. The family physician also notes some perianal involvement. The child is referred to the pediatric gastroenterologist, who evidences some patchy areas of ulcerations in the large bowel and difficulty to pass the ileocecal valve. Also, radiologic barium films showed a “string sign” in the terminal ileum. If your suspicion of diagnosis is correct, which statement is NOT valid for your diagnosis?

  • (a) Patchy lesions are usually seen on a biopsy taken during the endoscopy.

  • (b) Granulomas may be present at the histologic examination of the gastrointestinal biopsies.

  • (c) The annual incidence of this disease in North America is reported to be 3.1–20.2 per 10⁵ with a prevalence of 201 per 10⁵ population.

  • (d) Abnormalities of NOD2, IL23R, and ATG16L1 genes have been found associated with this disease.

  • (e) The Montreal classification is based on the age at diagnosis, disease location, the disease behavior, and the genotype.

• GIT-6 Ischemic colitis is not frequent in childhood or adolescence/youth, but it can occur and needs to be considered in the differential diagnosis if the clinical setting is appropriate. Which of the following statements is correct?

  • (a) The most common symptoms are periumbilical pain and bright red rectal bleeding.

  • (b) In most cases, the occlusion of the major mesenteric vessels is responsible for creating the ischemia.

  • (c) The most vulnerable regions are the splenic flexure and descending colon.

  • (d) Nonoperative management is not justified.

  • (e) Large genomic studies have identified an autosomal recessive inheritance pattern.

• GIT-7 Colorectal polyps are not rare in childhood and adolescence in a tertiary healthcare institution, which of the following structures is/are considered premalignant/precancerous?

  • (a) Tubular adenoma

  • (b) Tubulovillous adenoma

  • (c) Villous adenoma

  • (d) Hyperplastic polyp

  • (e) [b] and [c]

  • (f) [a], [b], and [c]

  • (g) All of the above

• GIT-8 Which TNM corresponds to the following definition of carcinoid of the appendix: “Tumor more than 2 cm but not more than 4 cm or with extension to the cecum”?

  • (a) pT2

  • (b) pT1b

  • (c) pT3

  • (d) pT4

• GIT-9 Which of the following statements is NOT correct regarding the TP53 gene?

  • (a) The human TP53 gene is located on chromosome 17p with 11 exons and 10 introns.

  • (b) In the order from N- to C-terminus, the functional domains include the transactivation domain, proline-rich domain, tetramerization domain, and the primary domain.

  • (c) Once activated, p53 upregulates its negative regulator, MDM2 (murine/human double minute 2) and MDM2 functions as an E3 ubiquitin-ligase, to regulate the ubiquitination of p53, which leads to its degradation.

  • (d) Depending on the specific context, p53 can induce cell cycle arrest, apoptosis, or senescence, in the presence of cellular stress (e.g., DNA damage, hypoxia, oncogene activation).

  • (e) Activation of p53 can trigger the mitochondrial (intrinsic), but not the death receptor-induced (extrinsic) apoptotic pathways.

• GIT-10 An 18-year-old boy presents with a presacral mass in the setting of a Currarino triad. What are the three components of the Currarino triad?

  • (a) The anomaly of the MNX1 gene, presacral mass, and anorectal malformation

  • (b) Presacral mass, Wilms’ tumor, and sacrococcygeal tumor

  • (c) Presacral mass, Wilms’ tumor, and sacrococcygeal tumor

  • (d) Partial sacral agenesis, presacral mass, and anorectal malformation

  • (e) Pelvis agenesis, post-sacral mass, and anorectal malformation