Gastrointestinal stromal tumors: Cytomorphologic spectrum in fine needle aspiration smears.

ABSTRACT

Objective: To study the variation in the cytologic features of gastrointestinal stromal tumors (GISTs) at different sites targeted by different modalities. Study design: Cytologic smears of 9 cases of gastrointestinal stromal tumors were reviewed with their histopathologic follow-up. Immuno-cytochemistry was performed where possible. Results: The study includes eight males and one female patient with an age range of 42 to 71 years. There were four classical cases of gastrointestinal stromal tumors that showed tight cellular bundles and fascicles of slender spindle cells with scant cytoplasm. The cytological features of three recurrent and one malignant case included moderately to markedly pleomorphic, plump spindle to ovoid cells with variable chromatin pattern and variable pale blue to vacuolated cytoplasm, present in loose clusters and singly. There was one case with classical gastrointestinal stromal tumor cytology but myxoid stroma. All other cases were confirmed with either CD117 immunostain and/or histopathology. Benign mucosal fragments from stomach or duodenal mucosa were observed in smears obtained by endoscopic ultrasound - fine needle aspiration (EUS FNA). Conclusion: The variability in cytologic features in GIST implies that a diagnosis of gastrointestinal stromal tumor should be rendered on cytology only in conjunction with immune-cytochemistry result of CD117.