Abstract
Background : Duodenal carcinoid tumors are relatively rare. We present a case of duodenal carcinoid tumor diagnosed by endoscopic ultrasonography with fine-needle aspiration (EUS-FNA). Diff-Quik bedside staining was useful in the diagnosis of such lesions.
Case : A 60-year-old man was found in abdominal ultrasound sonography to have a tumor 18 mm in diameter in duodenal submucosa and the pancreatic head. No Duodenal mucosal abnormality was observed in upper digestive endoscopy. EUS-FNA and cytological diagnosis were made using Diff-Quik staining. Cytological findings showed rosette formation, scattered binucleate or trinucleate cells, and salt-and-pepper chromatin patterns. An endocrine tumor was suspected, so additional aspirations were performed for a cell block specimen. Pap stain showed findings similar to Diff-Quik staining. The cell block specimen, which fixed all samples, showed clusters of atypical cells with intranuclear inclusion bodies. In immunostaining, atypical cells were positive for CD56 and synaptophysin. A tumor was later surgically resected. Histology of the excised specimen showed an alveolar tumor cell structure, vascular invasion, and lymph node metastasis. Immunostaining showed the lesion to be positive for CD56 and synaptophysin.
Conclusion : Cytological diagnosis with Diff-Quik staining is useful for cytologically diagnosing a carcinoid tumor.
