Primary Malignant Gastrointestinal Stromal Tumor (GIST) of the Gallbladder: Report of a Case

Developments in research on interstitial Cajal-like cells in the biliary tract

INTRODUCTION

Interstitial cells of Cajal (ICCs) are a special type of interstitial cells located in the gastrointestinal tract muscles. They are closely related to smooth muscle cells and neurons, participate in gastrointestinal motility and nerve signal transmission, and are pacemaker cells for gastrointestinal electrical activity. Research interest in ICCs has continuously grown since they were first discovered in 1893. Later, researchers discovered that they are also present in other organs, including the biliary tract, urethra, bladder, etc.; these cells were named interstitial Cajal-like cells (ICLCs), and attempts have been made to explain their relationships with certain diseases.

AREAS COVERED

This review paper summarizes the morphology, identification, classification, function, and distribution of ICLCs in the biliary tract and their relationship to biliary tract diseases.

EXPERT OPINION

Based on the function and distribution of ICLCs in the biliary tract system, ICLCs will provide a more reliable theoretical basis for the mechanisms of pathogenesis of and treatments for biliary tract diseases.

Primary Extragastrointestinal Stromal Tumours in the Hepatobiliary Tree and Telocytes

The first decade of the twenty-first century witnessed the presence and light microscopic, immunophenotypic, and ultrastructural characterization of interstitial Cajal-like cells (coined as 'telocytes') in virtually every extragastrointestinal site of the human body by Laurentiu M. Popescu and his co-workers. Not surprisingly, stromal tumours, immunophenotypically similar to that of telocytes [CD117 (c-KIT) +/CD34 +], have also been sporadically reported outside the tubular gut (so-called extragastrointestinal stromal tumours, EGISTs), including the gall bladder, liver, and pancreas. A meticulous literature search from January 2000 to November 2015 have found 9 such case reports of EGISTs in the gall bladder, 16 in the liver, and 31 occurring in the pancreas. The site wise mean age at presentation for these tumours were reported to be 62.2 ± 16.6, 50.9 ± 20.1, and 55.3 ± 14.3 years, respectively. Six of nine EGISTs in the gall bladder were associated with gallstones. On pathological evaluation, these tumours exhibited prominent spindled cell morphology and consistent expression of CD117/c-KIT and CD34 on immunohistochemistry and variable expression of vimentin and α-smooth muscle actin. The biological behaviour of hepatic and pancreatic lesions was favourable compared to that in the gall bladder, following definitive surgery with or without imatinib therapy. While the exact pathophysiologic role played by telocytes in various organs is yet to be fully elucidated, there seems to be a direct link between these enigmatic stromal cells and pathogenesis of gallstones and origin of EGISTs, and a hope for targeted therapies. Furthermore, the possible role of telocytes in hepatic regeneration and liver fibrosis opens a new dimension for futuristic research.

Primary extragastrointestinal stromal tumor of the pleura: A case report

Gastrointestinal stromal tumors (GISTs) are the most common type of mesenchymal tumor of the gastrointestinal tract. The stomach and small intestine are the most common sites of occurrence. GISTs are mesenchymal neoplasms originating from the interstitial cells of Cajal (ICCs), and are characterized by positivity for cluster of differentiation (CD) 117, also known as proto-oncogene c-Kit. While the majority of GISTs develop in the alimentary tract, in rare cases they may also be found in extragastrointestinal tissues. This type of GIST is known as an extragastrointestinal stromal tumor (EGIST). Despite the fact that EGISTs have been reported in the mesentery, omentum and retroperitoneum, primary intrathoracic EGISTs, arising from the pleura or lungs, are rare. The patient presented in the current study was a 40-year-old man, who presented with a cough and pyrexia, with pleural effusion on the left side. Multiple nodules throughout the parietal pleura were identified by thoracoscopy and a diagnosis of primary GIST of pleura was established, since they were positive for CD117 and discovered on GIST-1 and there was no evidence of gastrointestinal tumors. Subsequently, the patient was administered with imatinib and had no signs of disease recurrence 2 years later.