Metastatic hemangiopericytoma associated with microangiopathic hemolytic anemia: review and report of a case.

The hemangiopericytoma is an invasive tumor of vascular origin. No matter how benign the course and how circumscribed the mass, it must be considered a lesion with high malignant potential. In the case report here, a hemangiopericytoma of the pancreas with metastasis to the liver was associated with microangiopathic hemolytic anemia in a 78-year old woman. The anemia may have been present before the onset of metastasis. If so, it could have been a major factor in the breakdown of host response and could have initiated the malignant dissemination. Under these circumstances it could be an indicator of metastasis in patients with previously diagnosed tumors. However, there are many cases of metastatic malignancy associated with this anemia in which the opposite situation holds. The anemia is usually of extracorpuscular origin. Apparently intravascular coagula1ion caused by injury from tumor-cell aggregates in small vessels induces erythrocyte fragmentation in fibrin strands. A vicious cycle of cell fragmentation, vascular injury and fibrin strand formation completes the course. Analysis of the findings should be based upon more than a strictly pathologic approach; it should also be related to the new discoveries in cancer research.