The patient was a 51-year-old woman who was referred to the Internal Medicine department of our hospital after a splenic tumor 6 cm in size was detected during an examination in 2006. Although abdominal CT showed splenomegaly and areas of heterogeneous attenuation in the spleen, PET-CT showed only mildly increased FDG accumulation, a finding that did not strongly suggest malignancy. The patient was subsequently followed up on an outpatient basis, and no major changes were observed on imaging findings. However, because the possibility of malignancy could not be completely ruled out, splenectomy with distal pancreatectomy was performed. Although a large portion of the tumor was found to be angioma, proliferation of endothelial cells having an irregular arrangement or tendencies toward stratification and small size was observed in some parts, and the patient was diagnosed with hemangioendothelioma of intermediate malignancy. The patient followed a favorable postoperative course and was discharged 10 days after surgery. She is currently being followed up on an outpatient basis, and no findings indicating relapse have been observed at 8 months postoperatively.
Primary splenic tumors are rare, and among them hemangioendothelioma has been reported in only two cases in Japan. We report the present case with reference to literature.