Multifocal Giant Granular Cell Tumors of the Alimentary Canal With Concurrent Eosinophilic Gastrointestinal Disease

Granular cell tumors (GCTs) are rare, typically benign Schwann cell neoplasms; within the gastrointestinal (GI) tract, the esophagus is the most frequent site. Eosinophilic gastrointestinal diseases are chronic immune-mediated conditions encompassing eosinophilic esophagitis, gastroenteritis, and colitis. We describe a 49-year-old man with prior testicular seminoma, follicular thyroid carcinoma, and cutaneous GCTs who developed multifocal esophageal and rectal GCTs alongside eosinophilic esophagitis, esophagitis gastroenteritis, and esophagitis colitis, plus an incidental sigmoid neuroendocrine tumor (WHO grade 2). To our knowledge, this is the first reported case of concurrent multisegmental eosinophilic gastrointestinal diseases, multifocal GCTs, and a neuroendocrine tumors (NET), highlighting the need for vigilant endoscopic surveillance.