Cytomorphology of gastrointestinal stromal tumours: a comprehensive study

Background: Gastrointestinal stromal tumours (GIST) are a heterogenous group of neoplasms. The main aim of the study is to review cases of spindle cell and epithelioid cell neoplasms of the GI tract and classify them as GIST and Non GIST morphologically.Methods: The present study included 30 cases of ‘gastrointestinal stromal tumours (GIST). GIST cases were reviewed based on morphology and were classified into “Risk of metastasis” categories based on the size and mitotic activity.Results: The small intestine was the most commonly involved site (46.67%), followed by stomach (30%). Based on the size of the tumour and mitotic activity, the tumours were categorized as high risk (70%), intermediate risk (16.67%), low risk (6.67%), and very low risk (6.67%). High risk tumours predominated in all sites except the oesophagus. There was spindle cell predominance (76.8%) among all the cases. Epithelioid cells were seen in 36.7% of the cases.Conclusions: Identifying mitotic figures and counting of GIST was associated with problems and were due to uneven distribution of the mitotic figures, variable thickness of the section and presence of inflammatory cells. Inspite of the difficulty mitoses is still considered as a good prognostic marker