A Rare Case of Disseminated Granular Cell Tumors Throughout the Gastrointestinal Tract Diagnosed by Endoscopic Ultrasonography Associated With Endoscopic Mucosal Resection

Granular cell tumor (GCT) is a neoplasm of uncertain histopathological origin; therefore, no uniformly accepted treatment strategy has yet been established. Microscopically, it is characterized by eosinophilic granules. This tumor involves the skin and subcutaneous tissue. Gastrointestinal involvement is uncommon; however, isolated granular cell tumors of the esophagus, stomach, and colon, as well as multifocal lesions of the esophagus and stomach, have been reported. Diffuse involvement of the entire gastrointestinal tract has not been described. We report the case of a 20-year-old woman who presented with a chronic cough. Chest computed tomography revealed a retrotracheal mass, which was surgically resected and ultimately diagnosed as a GCT. Upper gastrointestinal endoscopy, performed to investigate dyspepsia, revealed multiple synchronous GCTs throughout the esophagus, stomach, and duodenum. Endoscopic ultrasound of the largest identified nodule revealed a well-defined hypoechoic lesion confined to the second hypoechoic layer; all remaining lesions demonstrated similar ultrasonographic features. This lesion was resected "in bloc" without adverse events using endoscopic mucosal resection for diagnostic and therapeutic purposes. Immunohistochemical (IHC) analysis demonstrated positivity for S100 and CD68, with expression of CD34 also observed. The patient has been followed on an outpatient basis, and symptoms of postprandial fullness and abdominal discomfort have been managed conservatively, with satisfactory symptomatic relief to date. Immunohistochemistry was sufficient for the definitive classification of the lesion as a GCT, and endoscopic mucosal resection appears to be an appropriate diagnostic approach for lesions larger than 20 mm. Furthermore, the authors discuss the optimal surveillance strategy for patients with disseminated GCTs of the gastrointestinal tract.