Pancreatic and gastric heterotopia in the gallbladder: A rare incidental finding

Abstract

Heterotopic or ectopic tissue is a congenital anomaly, which is defined as the presence of the tissue outside its normal location, without neural, vascular, or anatomic connection with the main body of an organ in which it normally exists. This tissue is usually discovered incidentally and may be asymptomatic or may present with nonspecific gastrointestinal (GI) symptoms. Pancreatic and gastric heterotopia are the two predominantly occurring heterotopic tissues in the GI tract.[ 1 2 ] The prevalence of ectopic pancreatic tissue in the GI tract ranges from 0.6% to 13.7% of autopsy series and it can be present anywhere in the GI tract with the most common localizations being stomach (27.5%), duodenum (25.5%), colon (15.9%), esophagus, and Meckel's diverticulum.[ 3 4 5 ] It is a rare finding in the gallbladder and its prevalence has not been ascertained due to lack of large-scale studies and systematic review of literature. Similarly, heterotopic gastric tissue is common throughout the GI tract from the tongue to the rectum,[ 6 7 ] but it is extremely rare in the gallbladder with only around 34 cases reported in literature so far, while other cases of different types of heterotopic tissues in the gallbladder such as liver tissue and others such as adrenal and thyroid tissues have been described.[ 8 ] The most common presentation of ectopic tissue in the gallbladder is colicky pain in the epigastrium or right upper quadrant sometimes associated with nausea and vomiting. Here, we are presenting two incidentally detected cases, each of gastric and pancreatic heterotopias in the gallbladder.

Heterotopic gastric mucosa in the gallbladder—a rare find

“…In a systematic review on this subject, it is described that this change is found equally in males and females, with an average age of 36.4 years [ 3 ]. Clinically, heterotopic gastric mucosa manifests symptoms such as colicky pain in the epigastric or right hypochondrium, associated with nausea and vomiting [ 1 ], although sometimes it can also be described as asymptomatic or even an accidental finding [ 4 ]. About 50% of patients had normal blood examination; however, sometimes they had elevated transaminases and gamma-glutamyltransferase or leukocytosis caused by disturbed bile flow leading to inflammatory reactions.…”

“…Heterotopic gastric mucosa in the gallbladder is a rare condition that raises many doubts regarding the causes of its development and the consequences thereof. There are some proposed causes for the appearance of heterotopic gastric mucosa, such as the entrapment of primitive gastric tissue [ 6 ], abnormal development, heterotopic differentiation or the metaplastic differentiation [ 1 ]. However, due to absence of a clear embryological explanation and the extreme rarity of the condition, the etiology of this situation remains unknown.…”

“…Thus, it is considered that carcinoma must be ruled out in polypoidal lesions of the gallbladder >1.0 cm due to the high incidence of gallbladder carcinoma in sessile polypoidal lesion [ 8 ]. Another possible consequence of the existence of gastric tissue in the gallbladder is ulceration [ 1 ].…”

“…Heterotopic or ectopic tissue is defined as the presence of tissue outside its normal location, devoid of neural, vascular or anatomic connection to the main body of an organ in which it normally exists [ 1 ]. Heterotopic gastric mucosa is most often located in the upper gastrointestinal tract [ 2 ].…”

“…The development of gastric mucosa in the gallbladder is a rare find, with ~34 cases reported in the existing literature. Other tissues such as liver, adrenal and thyroid have already been described in the gallbladder [ 1 ]. As heterotopic tissue may promote carcinogenesis of the gallbladder, close attention should be paid to any occurrence of such lesions in this anatomical region.…”