Abstract
In a case of giant cavernous hemagioma of the liver, accompanied consumption coagulopathy and storage pool syndrome were treated successfully by the surgical resection of the tumor. This paper presents the electron microscopic observations of the tumor specimens, with regards to possible causative factors of these complications in the tumor.
Most abnormal vessels observed in the specimens are fairly small in size, ranging from 5μ to 35μ in diameter and consist of thin endothelial cells with partially rough and fluffy luminal surface. In some endothelial cells, phagocytosis of lipid-like substances and endothelial disruption are observed. An usual distinct basement membrane surrounding the whole vessel circumference is not evident, although discontinuous basement membrane is seen in a few vessels. Pericytes are rarely seen.
Erythrocytes, leukocytes and platelets are seen in the subendothelial or interstitial space outside the vessels, whether endothelial gap is observed or not. In these abnormal vessel lumina, increased platelets of different types such as almost normal, degranulated and aggregated, are observed, suggesting a sequestration of platelets. Platelet aggregates are seen more frequently in bifurcation of the vessels. Rarely, a platelet thrombus protrudes from the lumen to the subendothelial space through the endothelial gap. In these small vessels, thrombi consist of platelets and sometimes leukocytes, and fibrin is scarcely seen. In larger vessels, contrarily, thrombi consist mostly of fibrin.
Rouleau formation of erythrocytes is seen in some of the small vessels, and fragmentation of erythrocytes is observed near the fibrin clots in larger vessels.
The ultreastructure of giant cavernous hemangioma of the liver in this case may explain morphologically its causality on consumption coagulopathy and acquired storage pool syndrome.
