Abstract
Background : We report on the cytological findings of spindle cell-type carcinoid tumor (NET G1) of the duodenum, which is difficult to differentiate from gastrointestinal stromal tumor.
Case : A 60-year-old man consulted another hospital complaining of epigastric hunger pain, and was diagnosed as having a pear-shaped polypoid tumor measuring about 20×10 mm in size at the superior duodenal angle by endoscopy. He was referred to our hospital for further management.
Endoscopic ultrasound-guided fine needle aspiration cytology showed spindle cells occurring in loose small clumps, or as single cells. The tumor cells had a spindle-shaped nucleus with uniformly fine granular chromatin and an eosinophilic small nucleolus. We suspected GIST or neuroendocrine tumor. Immunostaining revealed positive staining of the tumor cells for CD56, synaptophysin and chromogranin A, based on which we diagnosed the tumor as a carcinoid tumor. Examination of the resected tumor tissue by EMR showed epithelial cells with short spindle to spindle-shaped nucleous, with the tumor cells arranged in an alveolar, ribbon-like or cord-like pattern in the submucosa.
Conclusion : When spindle-shaped cells are seen in a duodenal submucosal tumor, it is necessary to consider the diagnosis of spindle cell-type carcinoid in the differential diagnosis, in addition to mesenchymal tumor.
