Fatal clinically unrecognized gastrointestinal bleeding from an ulcerated gastric GIST with layered organizing thrombi: An autopsy case.

Gastrointestinal stromal tumors (GISTs) may cause gastrointestinal bleeding, but the temporal course of repeated intratumoral hemorrhage preceding a fatal gastrointestinal bleeding event is rarely demonstrated morphologically at autopsy. A 79-year-old man with no known history of GIST was found dead at home after several days of malaise and loss of appetite. Medicolegal autopsy revealed an 8 × 8 cm gastric GIST with a crater-like mucosal ulcer and abundant tarry intestinal contents. The tumor contained grossly layered dark-red thrombi, whitish organized thrombi, and viable tumor tissue. Histologically, bland spindle cells were diffusely positive for c-kit and CD34, with a mitotic count of 0 mitoses/5 mm2 and no tumor necrosis, corresponding to AFIP category 3a. The thrombi showed markedly different stages of organization, including preserved fibrin-erythrocyte layering, neovascularization, hemosiderin deposition, fibrosis, and dystrophic calcification. A laminated thrombus extended from the intratumoral hemorrhagic area through the mucosal ulcer into the gastric lumen. Reconstruction of the largest tumor cross-section from seven contiguous blocks demonstrated the spatial continuity and temporal heterogeneity of these hemorrhagic lesions. The cause of death was hemorrhagic shock due to gastrointestinal bleeding from the ulcerated gastric GIST. This case shows that even a GIST with a low estimated risk of progressive disease can cause fatal hemorrhage and that extensive autopsy sampling may reconstruct the history of repeated intratumoral hemorrhage preceding the terminal gastrointestinal bleeding event.