Pathological findings in a case of bone marrow carcinosis due to gastric cancer complicated by disseminated intravascular coagulation and thrombotic microangiopathy.

An 80-year-old man was diagnosed with disseminated intravascular coagulation (DIC) and thrombotic microangiopathy (TMA) associated with mucin-producing gastric cancer with bone marrow metastasis. He died suddenly on the third day of hospitalization before chemotherapy. Microscopic autopsy findings revealed fibrin thrombi by phosphotungstic acid hematoxylin (PTAH) staining of the renal glomeruli, and platelet thrombi by von Willebrand Factor (Factor VIII Antigen) staining of the microvessels of the bleeding intestine. Tumor cells were negative for both stains. Staining of endothelial cells (EC) of the small vessels with thrombomodulin (TM) stain revealed destruction of EC structure. This patient was thought to have had systemic dissemination of solid tumor cells associated with DIC and TMA, the clinical course of which is extremely aggressive. Different types of thrombi were observed in different organs, such as the kidneys and small intestine, which supported the co-occurrence of DIC and TMA by microscopic pathological findings. These findings provide pathological evidence for the pathology of the concurrent development of DIC and TMA and show differences in the types of thrombi according to the blood vessel localization. Furthermore, the findings were highly suggestive of the mechanisms causing organ dysfunction, such as renal dysfunction, and gastrointestinal bleeding.