Giant gastrointestinal stromal tumour of rare sarcomatoid epithelioid subtype: case study and literature review.

Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the gastrointestinal tract, but they represent less than 3% of all gastrointestinal tract malignancies. This is a detailed case study of a 52-year-old male patient treated for very uncommon histological subtype of gastric GIST with atypical clinical presentation, asymptomatic progress and late diagnosis. The resected tumour, giant in diameters, was confirmed to represent the most rare histopathologic subtype of GISTs - sarcomatoid epithelioid GIST. We report this case and review the literature with a special focus on pathomorphological evaluation, biological aggressiveness and prognostic factors. To our knowledge this is the first report of giant GIST of very uncommon sarcomatoid epithelioid subtype. It is concluded that clinicians should pay attention to the fact that initial diagnosis may be delayed due to mildly asymptomatic and non-specific clinical presentation. Asymptomatic tumours diagnosed at a late stage, which is often the case, can be large on presentation. Prognosis for patients diagnosed with GIST depend on tumour size, mitotic rate, histopathologic subtype and tumour location. That is why early diagnosis and R0 resection, which is usually feasible and safe even in giant gastric sarcomatoid epithelioid subtype of GISTs, are the key factors for further treatment and good prognosis.