Gastrointestinal stromal tumor associated with obliterative foam cell vasculopathy.

The histologic spectrum of gastrointestinal stromal tumor (GIST) is wide, but as far as we are aware, a specific intraneoplastic vasculopathy has not been described in it. This is the first report of foam cell vasculopathy in a GIST. This combination of lesions arose in a 66-year-old obese woman in treatment for hypothyroidism, hypercholesterolemia and hypertension. The patient presented a 7 cm GIST, located in the anterior wall of the stomach, which histologically showed vessels of varying sizes with striking intimal foam cell infiltration, occasional fibrinoid necrosis, hyalinization, and marked luminal narrowing or occlusion. There was a transmural lymphocytic infiltrate predominantly involving the small vessels. As a consequence of the vasculopathy, extensive tumor areas showed cellular hydropic swelling and microcyst formation. No changes of vasculopathy were observed in non-tumor vessels. The foam cell vasculopathy we have documented was a diffuse process within the GIST, and can be considered an exceptional type of intratumor necrotizing vasculitis.